/src/exprtk/exprtk.hpp

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/*
 ******************************************************************
 *           C++ Mathematical Expression Toolkit Library          *
 *                                                                *
 * Author: Arash Partow (1999-2024)                               *
 * URL: https://www.partow.net/programming/exprtk/index.html      *
 *                                                                *
 * Copyright notice:                                              *
 * Free use of the C++ Mathematical Expression Toolkit Library is *
 * permitted under the guidelines and in accordance with the most *
 * current version of the MIT License.                            *
 * https://www.opensource.org/licenses/MIT                        *
 * SPDX-License-Identifier: MIT                                   *
 *                                                                *
 * Example expressions:                                           *
 * (00) (y + x / y) * (x - y / x)                                 *
 * (01) (x^2 / sin(2 * pi / y)) - x / 2                           *
 * (02) sqrt(1 - (x^2))                                           *
 * (03) 1 - sin(2 * x) + cos(pi / y)                              *
 * (04) a * exp(2 * t) + c                                        *
 * (05) if(((x + 2) == 3) and ((y + 5) <= 9), 1 + w, 2 / z)       *
 * (06) (avg(x,y) <= x + y ? x - y : x * y) + 2 * pi / x          *
 * (07) z := x + sin(2 * pi / y)                                  *
 * (08) u := 2 * (pi * z) / (w := x + cos(y / pi))                *
 * (09) clamp(-1, sin(2 * pi * x) + cos(y / 2 * pi), +1)          *
 * (10) inrange(-2, m, +2) == if(({-2 <= m} and [m <= +2]), 1, 0) *
 * (11) (2sin(x)cos(2y)7 + 1) == (2 * sin(x) * cos(2*y) * 7 + 1)  *
 * (12) (x ilike 's*ri?g') and [y < (3 z^7 + w)]                  *
 *                                                                *
 ******************************************************************
*/


#ifndef INCLUDE_EXPRTK_HPP
#define INCLUDE_EXPRTK_HPP


#include <algorithm>
#include <cassert>
#include <cctype>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <deque>
#include <functional>
#include <iterator>
#include <limits>
#include <list>
#include <map>
#include <set>
#include <stack>
#include <stdexcept>
#include <string>
#include <utility>
#include <vector>


namespace exprtk
{
   #ifdef exprtk_enable_debugging
     #define exprtk_debug(params) printf params
   #else
     #define exprtk_debug(params) (void)0
   #endif

   #define exprtk_error_location             \
   "exprtk.hpp:" + details::to_str(__LINE__) \

   #if __cplusplus >= 201103L
      #define exprtk_override override
      #define exprtk_final    final
      #define exprtk_delete   = delete
   #else
      #define exprtk_override
      #define exprtk_final
      #define exprtk_delete
   #endif

   #if __cplusplus >= 201603L
      #define exprtk_fallthrough [[fallthrough]];
   #elif (__cplusplus >= 201103L) && (defined(__GNUC__) && !defined(__clang__))
      #define exprtk_fallthrough [[gnu::fallthrough]];
   #else
      #ifndef _MSC_VER
         #define exprtk_fallthrough __attribute__ ((fallthrough));
      #else
         #define exprtk_fallthrough
      #endif
   #endif

   namespace details
   {
      typedef char                   char_t;
      typedef char_t*                char_ptr;
      typedef char_t const*          char_cptr;
      typedef unsigned char          uchar_t;
      typedef uchar_t*               uchar_ptr;
      typedef uchar_t const*         uchar_cptr;
      typedef unsigned long long int _uint64_t;
      typedef long long int          _int64_t;

      inline bool is_whitespace(const char_t c)
      {
         return (' '  == c) || ('\n' == c) ||
                ('\r' == c) || ('\t' == c) ||
                ('\b' == c) || ('\v' == c) ||
                ('\f' == c) ;
      }

      inline bool is_operator_char(const char_t c)
      {
         return ('+' == c) || ('-' == c) ||
                ('*' == c) || ('/' == c) ||
                ('^' == c) || ('<' == c) ||
                ('>' == c) || ('=' == c) ||
                (',' == c) || ('!' == c) ||
                ('(' == c) || (')' == c) ||
                ('[' == c) || (']' == c) ||
                ('{' == c) || ('}' == c) ||
                ('%' == c) || (':' == c) ||
                ('?' == c) || ('&' == c) ||
                ('|' == c) || (';' == c) ;
      }

      inline bool is_letter(const char_t c)
      {
         return (('a' <= c) && (c <= 'z')) ||
                (('A' <= c) && (c <= 'Z')) ;
      }

      inline bool is_digit(const char_t c)
      {
         return ('0' <= c) && (c <= '9');
      }

      inline bool is_letter_or_digit(const char_t c)
      {
         return is_letter(c) || is_digit(c);
      }

      inline bool is_left_bracket(const char_t c)
      {
         return ('(' == c) || ('[' == c) || ('{' == c);
      }

      inline bool is_right_bracket(const char_t c)
      {
         return (')' == c) || (']' == c) || ('}' == c);
      }

      inline bool is_bracket(const char_t c)
      {
         return is_left_bracket(c) || is_right_bracket(c);
      }

      inline bool is_sign(const char_t c)
      {
         return ('+' == c) || ('-' == c);
      }

      inline bool is_invalid(const char_t c)
      {
         return !is_whitespace   (c) &&
                !is_operator_char(c) &&
                !is_letter       (c) &&
                !is_digit        (c) &&
                ('.'  != c)          &&
                ('_'  != c)          &&
                ('$'  != c)          &&
                ('~'  != c)          &&
                ('\'' != c);
      }

      inline bool is_valid_string_char(const char_t c)
      {
         return std::isprint(static_cast<uchar_t>(c)) ||
                is_whitespace(c);
      }

      #ifndef exprtk_disable_caseinsensitivity
      inline void case_normalise(std::string& s)
      {
         for (std::size_t i = 0; i < s.size(); ++i)
         {
            s[i] = static_cast<std::string::value_type>(std::tolower(s[i]));
         }
      }

      inline bool imatch(const char_t c1, const char_t c2)
      {
         return std::tolower(c1) == std::tolower(c2);
      }

      inline bool imatch(const std::string& s1, const std::string& s2)
      {
         if (s1.size() == s2.size())
         {
            for (std::size_t i = 0; i < s1.size(); ++i)
            {
               if (std::tolower(s1[i]) != std::tolower(s2[i]))
               {
                  return false;
               }
            }

            return true;
         }

         return false;
      }

      struct ilesscompare
      {
         inline bool operator() (const std::string& s1, const std::string& s2) const
         {
            const std::size_t length = std::min(s1.size(),s2.size());

            for (std::size_t i = 0; i < length; ++i)
            {
               const char_t c1 = static_cast<char_t>(std::tolower(s1[i]));
               const char_t c2 = static_cast<char_t>(std::tolower(s2[i]));

               if (c1 < c2)
                  return true;
               else if (c2 < c1)
                  return false;
            }

            return s1.size() < s2.size();
         }
      };

      #else
      inline void case_normalise(std::string&)
      {}

      inline bool imatch(const char_t c1, const char_t c2)
      {
         return c1 == c2;
      }

      inline bool imatch(const std::string& s1, const std::string& s2)
      {
         return s1 == s2;
      }

      struct ilesscompare
      {
         inline bool operator() (const std::string& s1, const std::string& s2) const
         {
            return s1 < s2;
         }
      };
      #endif

      inline bool is_valid_sf_symbol(const std::string& symbol)
      {
         // Special function: $f12 or $F34
         return (4 == symbol.size())  &&
                ('$' == symbol[0])    &&
                imatch('f',symbol[1]) &&
                is_digit(symbol[2])   &&
                is_digit(symbol[3]);
      }

      inline const char_t& front(const std::string& s)
      {
         return s[0];
      }

      inline const char_t& back(const std::string& s)
      {
         return s[s.size() - 1];
      }

      template <typename SignedType>
      inline std::string to_str_impl(SignedType i)
      {
         if (0 == i)
            return std::string("0");

         std::string result;

         const int sign = (i < 0) ? -1 : 1;

         for ( ; i; i /= 10)
         {
            result += '0' + static_cast<char_t>(sign * (i % 10));
         }

         if (sign < 0)
         {
            result += '-';
         }

         std::reverse(result.begin(), result.end());

         return result;
      }

      inline std::string to_str(int i)
      {
         return to_str_impl(i);
      }

      inline std::string to_str(std::size_t i)
      {
         return to_str_impl(static_cast<long long int>(i));
      }

      inline bool is_hex_digit(const uchar_t digit)
      {
         return (('0' <= digit) && (digit <= '9')) ||
                (('A' <= digit) && (digit <= 'F')) ||
                (('a' <= digit) && (digit <= 'f')) ;
      }

      inline uchar_t hex_to_bin(uchar_t h)
      {
         if (('0' <= h) && (h <= '9'))
            return (h - '0');
         else
            return static_cast<uchar_t>(std::toupper(h) - 'A' + 10);
      }

      template <typename Iterator>
      inline bool parse_hex(Iterator& itr, Iterator end,
                            char_t& result)
      {
         if (
              (end ==  (itr    ))               ||
              (end ==  (itr + 1))               ||
              (end ==  (itr + 2))               ||
              (end ==  (itr + 3))               ||
              ('0' != *(itr    ))               ||
              ('X' != std::toupper(*(itr + 1))) ||
              (!is_hex_digit(*(itr + 2)))       ||
              (!is_hex_digit(*(itr + 3)))
            )
         {
            return false;
         }

         result = hex_to_bin(static_cast<uchar_t>(*(itr + 2))) << 4 |
                  hex_to_bin(static_cast<uchar_t>(*(itr + 3))) ;

         return true;
      }

      inline bool cleanup_escapes(std::string& s)
      {
         typedef std::string::iterator str_itr_t;

         str_itr_t itr1 = s.begin();
         str_itr_t itr2 = s.begin();
         str_itr_t end  = s.end  ();

         std::size_t removal_count  = 0;

         while (end != itr1)
         {
            if ('\\' == (*itr1))
            {
               if (end == ++itr1)
               {
                  return false;
               }
               else if (parse_hex(itr1, end, *itr2))
               {
                  itr1 += 4;
                  itr2 += 1;
                  removal_count += 4;
               }
               else if ('a' == (*itr1)) { (*itr2++) = '\a'; ++itr1; ++removal_count; }
               else if ('b' == (*itr1)) { (*itr2++) = '\b'; ++itr1; ++removal_count; }
               else if ('f' == (*itr1)) { (*itr2++) = '\f'; ++itr1; ++removal_count; }
               else if ('n' == (*itr1)) { (*itr2++) = '\n'; ++itr1; ++removal_count; }
               else if ('r' == (*itr1)) { (*itr2++) = '\r'; ++itr1; ++removal_count; }
               else if ('t' == (*itr1)) { (*itr2++) = '\t'; ++itr1; ++removal_count; }
               else if ('v' == (*itr1)) { (*itr2++) = '\v'; ++itr1; ++removal_count; }
               else if ('0' == (*itr1)) { (*itr2++) = '\0'; ++itr1; ++removal_count; }
               else
               {
                  (*itr2++) = (*itr1++);
                  ++removal_count;
               }

               continue;
            }
            else
               (*itr2++) = (*itr1++);
         }

         if ((removal_count > s.size()) || (0 == removal_count))
            return false;

         s.resize(s.size() - removal_count);

         return true;
      }

      class build_string
      {
      public:

         explicit build_string(const std::size_t& initial_size = 64)
         {
            data_.reserve(initial_size);
         }

         inline build_string& operator << (const std::string& s)
         {
            data_ += s;
            return (*this);
         }

         inline build_string& operator << (char_cptr s)
         {
            data_ += std::string(s);
            return (*this);
         }

         inline operator std::string () const
         {
            return data_;
         }

         inline std::string as_string() const
         {
            return data_;
         }

      private:

         std::string data_;
      };

      static const std::string reserved_words[] =
      {
         "assert",  "break", "case", "continue", "const",  "default",
         "false", "for", "if", "else", "ilike", "in", "like",  "and",
         "nand",  "nor",  "not",  "null",  "or",  "repeat", "return",
         "shl",  "shr",  "swap",  "switch",  "true",  "until", "var",
         "while", "xnor", "xor", "&", "|"
      };

      static const std::size_t reserved_words_size = sizeof(reserved_words) / sizeof(std::string);

      static const std::string reserved_symbols[] =
      {
         "abs", "acos",  "acosh", "and",  "asin", "asinh",  "assert",
         "atan", "atanh",  "atan2", "avg",  "break", "case",  "ceil",
         "clamp", "continue", "const",  "cos", "cosh", "cot",  "csc",
         "default",  "deg2grad", "deg2rad",  "equal", "erf",  "erfc",
         "exp", "expm1", "false", "floor", "for", "frac", "grad2deg",
         "hypot", "iclamp", "if",  "else", "ilike", "in",  "inrange",
         "like",  "log",  "log10", "log2",  "logn",  "log1p", "mand",
         "max", "min",  "mod", "mor",  "mul", "ncdf",  "nand", "nor",
         "not",   "not_equal",   "null",   "or",   "pow",  "rad2deg",
         "repeat", "return", "root", "round", "roundn", "sec", "sgn",
         "shl", "shr", "sin", "sinc", "sinh", "sqrt", "sum",  "swap",
         "switch", "tan",  "tanh", "true",  "trunc", "until",  "var",
         "while", "xnor", "xor", "&", "|"
      };

      static const std::size_t reserved_symbols_size = sizeof(reserved_symbols) / sizeof(std::string);

      static const std::string base_function_list[] =
      {
         "abs", "acos",  "acosh", "asin",  "asinh", "atan",  "atanh",
         "atan2",  "avg",  "ceil",  "clamp",  "cos",  "cosh",  "cot",
         "csc",  "equal",  "erf",  "erfc",  "exp",  "expm1", "floor",
         "frac", "hypot", "iclamp",  "like", "log", "log10",  "log2",
         "logn", "log1p", "mand", "max", "min", "mod", "mor",  "mul",
         "ncdf",  "pow",  "root",  "round",  "roundn",  "sec", "sgn",
         "sin", "sinc", "sinh", "sqrt", "sum", "swap", "tan", "tanh",
         "trunc",  "not_equal",  "inrange",  "deg2grad",   "deg2rad",
         "rad2deg", "grad2deg"
      };

      static const std::size_t base_function_list_size = sizeof(base_function_list) / sizeof(std::string);

      static const std::string logic_ops_list[] =
      {
         "and", "nand", "nor", "not", "or",  "xnor", "xor", "&", "|"
      };

      static const std::size_t logic_ops_list_size = sizeof(logic_ops_list) / sizeof(std::string);

      static const std::string cntrl_struct_list[] =
      {
         "if", "switch", "for", "while", "repeat", "return"
      };

      static const std::size_t cntrl_struct_list_size = sizeof(cntrl_struct_list) / sizeof(std::string);

      static const std::string arithmetic_ops_list[] =
      {
         "+", "-", "*", "/", "%", "^"
      };

      static const std::size_t arithmetic_ops_list_size = sizeof(arithmetic_ops_list) / sizeof(std::string);

      static const std::string assignment_ops_list[] =
      {
         ":=", "+=", "-=",
         "*=", "/=", "%="
      };

      static const std::size_t assignment_ops_list_size = sizeof(assignment_ops_list) / sizeof(std::string);

      static const std::string inequality_ops_list[] =
      {
         "<",  "<=", "==",
         "=",  "!=", "<>",
         ">=",  ">"
      };

      static const std::size_t inequality_ops_list_size = sizeof(inequality_ops_list) / sizeof(std::string);

      inline bool is_reserved_word(const std::string& symbol)
      {
         for (std::size_t i = 0; i < reserved_words_size; ++i)
         {
            if (imatch(symbol, reserved_words[i]))
            {
               return true;
            }
         }

         return false;
      }

      inline bool is_reserved_symbol(const std::string& symbol)
      {
         for (std::size_t i = 0; i < reserved_symbols_size; ++i)
         {
            if (imatch(symbol, reserved_symbols[i]))
            {
               return true;
            }
         }

         return false;
      }

      inline bool is_base_function(const std::string& function_name)
      {
         for (std::size_t i = 0; i < base_function_list_size; ++i)
         {
            if (imatch(function_name, base_function_list[i]))
            {
               return true;
            }
         }

         return false;
      }

      inline bool is_control_struct(const std::string& cntrl_strct)
      {
         for (std::size_t i = 0; i < cntrl_struct_list_size; ++i)
         {
            if (imatch(cntrl_strct, cntrl_struct_list[i]))
            {
               return true;
            }
         }

         return false;
      }

      inline bool is_logic_opr(const std::string& lgc_opr)
      {
         for (std::size_t i = 0; i < logic_ops_list_size; ++i)
         {
            if (imatch(lgc_opr, logic_ops_list[i]))
            {
               return true;
            }
         }

         return false;
      }

      struct cs_match
      {
         static inline bool cmp(const char_t c0, const char_t c1)
         {
            return (c0 == c1);
         }
      };

      struct cis_match
      {
         static inline bool cmp(const char_t c0, const char_t c1)
         {
            return (std::tolower(c0) == std::tolower(c1));
         }
      };

      template <typename Iterator, typename Compare>
      inline bool match_impl(const Iterator pattern_begin,
                             const Iterator pattern_end  ,
                             const Iterator data_begin   ,
                             const Iterator data_end     ,
                             const typename std::iterator_traits<Iterator>::value_type& zero_or_more,
                             const typename std::iterator_traits<Iterator>::value_type& exactly_one )
      {
         typedef typename std::iterator_traits<Iterator>::value_type type;

         const Iterator null_itr(0);

         Iterator p_itr  = pattern_begin;
         Iterator d_itr  = data_begin;
         Iterator np_itr = null_itr;
         Iterator nd_itr = null_itr;

         for ( ; ; )
         {
            if (p_itr != pattern_end)
            {
               const type c = *(p_itr);

               if ((data_end != d_itr) && (Compare::cmp(c,*(d_itr)) || (exactly_one == c)))
               {
                  ++d_itr;
                  ++p_itr;
                  continue;
               }
               else if (zero_or_more == c)
               {
                  while ((pattern_end != p_itr) && (zero_or_more == *(p_itr)))
                  {
                     ++p_itr;
                  }

                  const type d = *(p_itr);

                  while ((data_end != d_itr) && !(Compare::cmp(d,*(d_itr)) || (exactly_one == d)))
                  {
                     ++d_itr;
                  }

                  // set backtrack iterators
                  np_itr = p_itr - 1;
                  nd_itr = d_itr + 1;

                  continue;
               }
            }
            else if (data_end == d_itr)
               break;

            if ((data_end == d_itr) || (null_itr == nd_itr))
                return false;

            p_itr = np_itr;
            d_itr = nd_itr;
         }

         return true;
      }

      inline bool wc_match(const std::string& wild_card,
                           const std::string& str)
      {
         return match_impl<char_cptr,cs_match>
                (
                   wild_card.data(),
                   wild_card.data() + wild_card.size(),
                   str.data(),
                   str.data() + str.size(),
                   '*', '?'
                );
      }

      inline bool wc_imatch(const std::string& wild_card,
                            const std::string& str)
      {
         return match_impl<char_cptr,cis_match>
                (
                   wild_card.data(),
                   wild_card.data() + wild_card.size(),
                   str.data(),
                   str.data() + str.size(),
                   '*', '?'
                );
      }

      inline bool sequence_match(const std::string& pattern,
                                 const std::string& str,
                                 std::size_t&       diff_index,
                                 char_t&            diff_value)
      {
         if (str.empty())
         {
            return ("Z" == pattern);
         }
         else if ('*' == pattern[0])
            return false;

         typedef std::string::const_iterator itr_t;

         itr_t p_itr = pattern.begin();
         itr_t s_itr = str    .begin();

         const itr_t p_end = pattern.end();
         const itr_t s_end = str    .end();

         while ((s_end != s_itr) && (p_end != p_itr))
         {
            if ('*' == (*p_itr))
            {
               const char_t target = static_cast<char_t>(std::toupper(*(p_itr - 1)));

               if ('*' == target)
               {
                  diff_index = static_cast<std::size_t>(std::distance(str.begin(),s_itr));
                  diff_value = static_cast<char_t>(std::toupper(*p_itr));

                  return false;
               }
               else
                  ++p_itr;

               while (s_itr != s_end)
               {
                  if (target != std::toupper(*s_itr))
                     break;
                  else
                     ++s_itr;
               }

               continue;
            }
            else if (
                      ('?' != *p_itr) &&
                      std::toupper(*p_itr) != std::toupper(*s_itr)
                    )
            {
               diff_index = static_cast<std::size_t>(std::distance(str.begin(),s_itr));
               diff_value = static_cast<char_t>(std::toupper(*p_itr));

               return false;
            }

            ++p_itr;
            ++s_itr;
         }

         return (
                  (s_end == s_itr) &&
                  (
                    (p_end ==  p_itr) ||
                    ('*'   == *p_itr)
                  )
                );
      }

      template<typename T>
      struct set_zero_value_impl
      {
         static inline void process(T* base_ptr, const std::size_t size)
         {
            const T zero = T(0);
            for (std::size_t i = 0; i < size; ++i)
            {
               base_ptr[i] = zero;
            }
         }
      };

      #define pod_set_zero_value(T)                                      \
      template <>                                                        \
      struct set_zero_value_impl<T>                                      \
      {                                                                  \
         static inline void process(T* base_ptr, const std::size_t size) \
         { std::memset(base_ptr, 0x00, size * sizeof(T)); }              \
      };                                                                 \

      pod_set_zero_value(float      )
      pod_set_zero_value(double     )
      pod_set_zero_value(long double)

      #ifdef pod_set_zero_value
      #undef pod_set_zero_value
      #endif

      template<typename T>
      inline void set_zero_value(T* data, const std::size_t size)
      {
         set_zero_value_impl<T>::process(data,size);
      }

      template<typename T>
      inline void set_zero_value(std::vector<T>& v)
      {
         set_zero_value(v.data(),v.size());
      }

      static const double pow10[] =
      {
         1.0,
         1.0E+001, 1.0E+002, 1.0E+003, 1.0E+004,
         1.0E+005, 1.0E+006, 1.0E+007, 1.0E+008,
         1.0E+009, 1.0E+010, 1.0E+011, 1.0E+012,
         1.0E+013, 1.0E+014, 1.0E+015, 1.0E+016
      };

      static const std::size_t pow10_size = sizeof(pow10) / sizeof(double);

      namespace numeric
      {
         namespace constant
         {
            static const double e       =  2.71828182845904523536028747135266249775724709369996;
            static const double pi      =  3.14159265358979323846264338327950288419716939937510;
            static const double pi_2    =  1.57079632679489661923132169163975144209858469968755;
            static const double pi_4    =  0.78539816339744830961566084581987572104929234984378;
            static const double pi_180  =  0.01745329251994329576923690768488612713442871888542;
            static const double _1_pi   =  0.31830988618379067153776752674502872406891929148091;
            static const double _2_pi   =  0.63661977236758134307553505349005744813783858296183;
            static const double _180_pi = 57.29577951308232087679815481410517033240547246656443;
            static const double log2    =  0.69314718055994530941723212145817656807550013436026;
            static const double sqrt2   =  1.41421356237309504880168872420969807856967187537695;
         }

         namespace details
         {
            struct unknown_type_tag { unknown_type_tag() {} };
            struct real_type_tag    { real_type_tag   () {} };
            struct int_type_tag     { int_type_tag    () {} };

            template <typename T>
            struct number_type
            {
               typedef unknown_type_tag type;
               number_type() {}
            };

            #define exprtk_register_real_type_tag(T)          \
            template <> struct number_type<T>                 \
            { typedef real_type_tag type; number_type() {} }; \

            #define exprtk_register_int_type_tag(T)           \
            template <> struct number_type<T>                 \
            { typedef int_type_tag type; number_type() {} };  \

            exprtk_register_real_type_tag(float      )
            exprtk_register_real_type_tag(double     )
            exprtk_register_real_type_tag(long double)

            exprtk_register_int_type_tag(short         )
            exprtk_register_int_type_tag(int           )
            exprtk_register_int_type_tag(_int64_t      )
            exprtk_register_int_type_tag(unsigned short)
            exprtk_register_int_type_tag(unsigned int  )
            exprtk_register_int_type_tag(_uint64_t     )

            #undef exprtk_register_real_type_tag
            #undef exprtk_register_int_type_tag

            template <typename T>
            struct epsilon_type {};

            #define exprtk_define_epsilon_type(Type, Epsilon)      \
            template <> struct epsilon_type<Type>                  \
            {                                                      \
               static inline Type value()                          \
               {                                                   \
                  const Type epsilon = static_cast<Type>(Epsilon); \
                  return epsilon;                                  \
               }                                                   \
            };                                                     \

            exprtk_define_epsilon_type(float      , 0.00000100000f)
            exprtk_define_epsilon_type(double     , 0.000000000100)
            exprtk_define_epsilon_type(long double, 0.000000000001)

            #undef exprtk_define_epsilon_type

            template <typename T>
            inline bool is_nan_impl(const T v, real_type_tag)
            {
               return std::not_equal_to<T>()(v,v);
            }

            template <typename T>
            inline int to_int32_impl(const T v, real_type_tag)
            {
               return static_cast<int>(v);
            }

            template <typename T>
            inline _int64_t to_int64_impl(const T v, real_type_tag)
            {
               return static_cast<_int64_t>(v);
            }

            template <typename T>
            inline _uint64_t to_uint64_impl(const T v, real_type_tag)
            {
               return static_cast<_uint64_t>(v);
            }

            template <typename T>
            inline bool is_true_impl(const T v)
            {
               return std::not_equal_to<T>()(T(0),v);
            }

            template <typename T>
            inline bool is_false_impl(const T v)
            {
               return std::equal_to<T>()(T(0),v);
            }

            template <typename T>
            inline T abs_impl(const T v, real_type_tag)
            {
               return ((v < T(0)) ? -v : v);
            }

            template <typename T>
            inline T min_impl(const T v0, const T v1, real_type_tag)
            {
               return std::min<T>(v0,v1);
            }

            template <typename T>
            inline T max_impl(const T v0, const T v1, real_type_tag)
            {
               return std::max<T>(v0,v1);
            }

            template <typename T>
            inline T equal_impl(const T v0, const T v1, real_type_tag)
            {
               const T epsilon = epsilon_type<T>::value();
               return (abs_impl(v0 - v1,real_type_tag()) <= (std::max(T(1),std::max(abs_impl(v0,real_type_tag()),abs_impl(v1,real_type_tag()))) * epsilon)) ? T(1) : T(0);
            }

            inline float equal_impl(const float v0, const float v1, real_type_tag)
            {
               const float epsilon = epsilon_type<float>::value();
               return (abs_impl(v0 - v1,real_type_tag()) <= (std::max(1.0f,std::max(abs_impl(v0,real_type_tag()),abs_impl(v1,real_type_tag()))) * epsilon)) ? 1.0f : 0.0f;
            }

            template <typename T>
            inline T equal_impl(const T v0, const T v1, int_type_tag)
            {
               return (v0 == v1) ? 1 : 0;
            }

            template <typename T>
            inline T nequal_impl(const T v0, const T v1, real_type_tag)
            {
               typedef real_type_tag rtg;
               const T epsilon = epsilon_type<T>::value();
               return (abs_impl(v0 - v1,rtg()) > (std::max(T(1),std::max(abs_impl(v0,rtg()),abs_impl(v1,rtg()))) * epsilon)) ? T(1) : T(0);
            }

            inline float nequal_impl(const float v0, const float v1, real_type_tag)
            {
               typedef real_type_tag rtg;
               const float epsilon = epsilon_type<float>::value();
               return (abs_impl(v0 - v1,rtg()) > (std::max(1.0f,std::max(abs_impl(v0,rtg()),abs_impl(v1,rtg()))) * epsilon)) ? 1.0f : 0.0f;
            }

            template <typename T>
            inline T nequal_impl(const T v0, const T v1, int_type_tag)
            {
               return (v0 != v1) ? 1 : 0;
            }

            template <typename T>
            inline T modulus_impl(const T v0, const T v1, real_type_tag)
            {
               return std::fmod(v0,v1);
            }

            template <typename T>
            inline T modulus_impl(const T v0, const T v1, int_type_tag)
            {
               return v0 % v1;
            }

            template <typename T>
            inline T pow_impl(const T v0, const T v1, real_type_tag)
            {
               return std::pow(v0,v1);
            }

            template <typename T>
            inline T pow_impl(const T v0, const T v1, int_type_tag)
            {
               return std::pow(static_cast<double>(v0),static_cast<double>(v1));
            }

            template <typename T>
            inline T logn_impl(const T v0, const T v1, real_type_tag)
            {
               return std::log(v0) / std::log(v1);
            }

            template <typename T>
            inline T logn_impl(const T v0, const T v1, int_type_tag)
            {
               return static_cast<T>(logn_impl<double>(static_cast<double>(v0),static_cast<double>(v1),real_type_tag()));
            }

            template <typename T>
            inline T root_impl(const T v0, const T v1, real_type_tag)
            {
               if (v0 < T(0))
               {
                  return (v1 == trunc_impl(v1, real_type_tag())) &&
                         (modulus_impl(v1, T(2), real_type_tag()) != T(0)) ?
                         -std::pow(abs_impl(v0, real_type_tag()), T(1) / v1) :
                          std::numeric_limits<double>::quiet_NaN();
               }

               return std::pow(v0, T(1) / v1);
            }

            template <typename T>
            inline T root_impl(const T v0, const T v1, int_type_tag)
            {
               return root_impl<double>(static_cast<double>(v0),static_cast<double>(v1),real_type_tag());
            }

            template <typename T>
            inline T round_impl(const T v, real_type_tag)
            {
               return ((v < T(0)) ? std::ceil(v - T(0.5)) : std::floor(v + T(0.5)));
            }

            template <typename T>
            inline T roundn_impl(const T v0, const T v1, real_type_tag)
            {
               const int index = std::max<int>(0, std::min<int>(pow10_size - 1, static_cast<int>(std::floor(v1))));
               const T p10 = T(pow10[index]);

               if (v0 < T(0))
                  return T(std::ceil ((v0 * p10) - T(0.5)) / p10);
               else
                  return T(std::floor((v0 * p10) + T(0.5)) / p10);
            }

            template <typename T>
            inline T roundn_impl(const T v0, const T, int_type_tag)
            {
               return v0;
            }

            template <typename T>
            inline T hypot_impl(const T v0, const T v1, real_type_tag)
            {
               return std::sqrt((v0 * v0) + (v1 * v1));
            }

            template <typename T>
            inline T hypot_impl(const T v0, const T v1, int_type_tag)
            {
               return static_cast<T>(std::sqrt(static_cast<double>((v0 * v0) + (v1 * v1))));
            }

            template <typename T>
            inline T atan2_impl(const T v0, const T v1, real_type_tag)
            {
               return std::atan2(v0,v1);
            }

            template <typename T>
            inline T atan2_impl(const T, const T, int_type_tag)
            {
               return 0;
            }

            template <typename T>
            inline T shr_impl(const T v0, const T v1, real_type_tag)
            {
               return v0 * (T(1) / std::pow(T(2),static_cast<T>(static_cast<int>(v1))));
            }

            template <typename T>
            inline T shr_impl(const T v0, const T v1, int_type_tag)
            {
               return v0 >> v1;
            }

            template <typename T>
            inline T shl_impl(const T v0, const T v1, real_type_tag)
            {
               return v0 * std::pow(T(2),static_cast<T>(static_cast<int>(v1)));
            }

            template <typename T>
            inline T shl_impl(const T v0, const T v1, int_type_tag)
            {
               return v0 << v1;
            }

            template <typename T>
            inline T sgn_impl(const T v, real_type_tag)
            {
               if      (v > T(0)) return T(+1);
               else if (v < T(0)) return T(-1);
               else               return T( 0);
            }

            template <typename T>
            inline T sgn_impl(const T v, int_type_tag)
            {
               if      (v > T(0)) return T(+1);
               else if (v < T(0)) return T(-1);
               else               return T( 0);
            }

            template <typename T>
            inline T and_impl(const T v0, const T v1, real_type_tag)
            {
               return (is_true_impl(v0) && is_true_impl(v1)) ? T(1) : T(0);
            }

            template <typename T>
            inline T and_impl(const T v0, const T v1, int_type_tag)
            {
               return v0 && v1;
            }

            template <typename T>
            inline T nand_impl(const T v0, const T v1, real_type_tag)
            {
               return (is_false_impl(v0) || is_false_impl(v1)) ? T(1) : T(0);
            }

            template <typename T>
            inline T nand_impl(const T v0, const T v1, int_type_tag)
            {
               return !(v0 && v1);
            }

            template <typename T>
            inline T or_impl(const T v0, const T v1, real_type_tag)
            {
               return (is_true_impl(v0) || is_true_impl(v1)) ? T(1) : T(0);
            }

            template <typename T>
            inline T or_impl(const T v0, const T v1, int_type_tag)
            {
               return (v0 || v1);
            }

            template <typename T>
            inline T nor_impl(const T v0, const T v1, real_type_tag)
            {
               return (is_false_impl(v0) && is_false_impl(v1)) ? T(1) : T(0);
            }

            template <typename T>
            inline T nor_impl(const T v0, const T v1, int_type_tag)
            {
               return !(v0 || v1);
            }

            template <typename T>
            inline T xor_impl(const T v0, const T v1, real_type_tag)
            {
               return (is_false_impl(v0) != is_false_impl(v1)) ? T(1) : T(0);
            }

            template <typename T>
            inline T xor_impl(const T v0, const T v1, int_type_tag)
            {
               return v0 ^ v1;
            }

            template <typename T>
            inline T xnor_impl(const T v0, const T v1, real_type_tag)
            {
               const bool v0_true = is_true_impl(v0);
               const bool v1_true = is_true_impl(v1);

               if ((v0_true &&  v1_true) || (!v0_true && !v1_true))
                  return T(1);
               else
                  return T(0);
            }

            template <typename T>
            inline T xnor_impl(const T v0, const T v1, int_type_tag)
            {
               const bool v0_true = is_true_impl(v0);
               const bool v1_true = is_true_impl(v1);

               if ((v0_true &&  v1_true) || (!v0_true && !v1_true))
                  return T(1);
               else
                  return T(0);
            }

            #if (defined(_MSC_VER) && (_MSC_VER >= 1900)) || !defined(_MSC_VER)
            #define exprtk_define_erf(TT, impl)                \
            inline TT erf_impl(const TT v) { return impl(v); } \

            exprtk_define_erf(float      , ::erff)
            exprtk_define_erf(double     , ::erf )
            exprtk_define_erf(long double, ::erfl)
            #undef exprtk_define_erf
            #endif

            template <typename T>
            inline T erf_impl(const T v, real_type_tag)
            {
               #if defined(_MSC_VER) && (_MSC_VER < 1900)
               // Credits: Abramowitz & Stegun Equations 7.1.25-28
               static const T c[] =
               {
                  T( 1.26551223), T(1.00002368),
                  T( 0.37409196), T(0.09678418),
                  T(-0.18628806), T(0.27886807),
                  T(-1.13520398), T(1.48851587),
                  T(-0.82215223), T(0.17087277)
               };

               const T t = T(1) / (T(1) + T(0.5) * abs_impl(v,real_type_tag()));

               const T result = T(1) - t * std::exp((-v * v) -
                                            c[0] + t * (c[1] + t *
                                           (c[2] + t * (c[3] + t *
                                           (c[4] + t * (c[5] + t *
                                           (c[6] + t * (c[7] + t *
                                           (c[8] + t * (c[9]))))))))));

               return (v >= T(0)) ? result : -result;
               #else
               return erf_impl(v);
               #endif
            }

            template <typename T>
            inline T erf_impl(const T v, int_type_tag)
            {
               return erf_impl(static_cast<double>(v),real_type_tag());
            }

            #if (defined(_MSC_VER) && (_MSC_VER >= 1900)) || !defined(_MSC_VER)
            #define exprtk_define_erfc(TT, impl)                \
            inline TT erfc_impl(const TT v) { return impl(v); } \

            exprtk_define_erfc(float      ,::erfcf)
            exprtk_define_erfc(double     ,::erfc )
            exprtk_define_erfc(long double,::erfcl)
            #undef exprtk_define_erfc
            #endif

            template <typename T>
            inline T erfc_impl(const T v, real_type_tag)
            {
               #if defined(_MSC_VER) && (_MSC_VER < 1900)
               return T(1) - erf_impl(v,real_type_tag());
               #else
               return erfc_impl(v);
               #endif
            }

            template <typename T>
            inline T erfc_impl(const T v, int_type_tag)
            {
               return erfc_impl(static_cast<double>(v),real_type_tag());
            }

            template <typename T>
            inline T ncdf_impl(const T v, real_type_tag)
            {
               return T(0.5) * erfc_impl(-(v / T(numeric::constant::sqrt2)),real_type_tag());
            }

            template <typename T>
            inline T ncdf_impl(const T v, int_type_tag)
            {
               return ncdf_impl(static_cast<double>(v),real_type_tag());
            }

            template <typename T>
            inline T sinc_impl(const T v, real_type_tag)
            {
               if (std::abs(v) >= std::numeric_limits<T>::epsilon())
                   return(std::sin(v) / v);
               else
                  return T(1);
            }

            template <typename T>
            inline T sinc_impl(const T v, int_type_tag)
            {
               return sinc_impl(static_cast<double>(v),real_type_tag());
            }

            #if __cplusplus >= 201103L
            template <typename T>
            inline T acosh_impl(const T v, real_type_tag)
            {
               return std::acosh(v);
            }

            template <typename T>
            inline T asinh_impl(const T v, real_type_tag)
            {
               return std::asinh(v);
            }

            template <typename T>
            inline T atanh_impl(const T v, real_type_tag)
            {
               return std::atanh(v);
            }

            template <typename T>
            inline T trunc_impl(const T v, real_type_tag)
            {
               return std::trunc(v);
            }

            template <typename T>
            inline T expm1_impl(const T v, real_type_tag)
            {
               return std::expm1(v);
            }

            template <typename T>
            inline T expm1_impl(const T v, int_type_tag)
            {
               return std::expm1(v);
            }

            template <typename T>
            inline T log1p_impl(const T v, real_type_tag)
            {
               return std::log1p(v);
            }

            template <typename T>
            inline T log1p_impl(const T v, int_type_tag)
            {
               return std::log1p(v);
            }
            #else
            template <typename T>
            inline T acosh_impl(const T v, real_type_tag)
            {
               return std::log(v + std::sqrt((v * v) - T(1)));
            }

            template <typename T>
            inline T asinh_impl(const T v, real_type_tag)
            {
               return std::log(v + std::sqrt((v * v) + T(1)));
            }

            template <typename T>
            inline T atanh_impl(const T v, real_type_tag)
            {
               return (std::log(T(1) + v) - std::log(T(1) - v)) / T(2);
            }

            template <typename T>
            inline T trunc_impl(const T v, real_type_tag)
            {
               return T(static_cast<long long>(v));
            }

            template <typename T>
            inline T expm1_impl(const T v, real_type_tag)
            {
               if (abs_impl(v,real_type_tag()) < T(0.00001))
                  return v + (T(0.5) * v * v);
               else
                  return std::exp(v) - T(1);
            }

            template <typename T>
            inline T expm1_impl(const T v, int_type_tag)
            {
               return T(std::exp<double>(v)) - T(1);
            }

            template <typename T>
            inline T log1p_impl(const T v, real_type_tag)
            {
               if (v > T(-1))
               {
                  if (abs_impl(v,real_type_tag()) > T(0.0001))
                  {
                     return std::log(T(1) + v);
                  }
                  else
                     return (T(-0.5) * v + T(1)) * v;
               }

               return std::numeric_limits<T>::quiet_NaN();
            }

            template <typename T>
            inline T log1p_impl(const T v, int_type_tag)
            {
               if (v > T(-1))
               {
                  return std::log(T(1) + v);
               }

               return std::numeric_limits<T>::quiet_NaN();
            }
            #endif

            template <typename T> inline T  acos_impl(const T v, real_type_tag) { return std::acos (v); }
            template <typename T> inline T  asin_impl(const T v, real_type_tag) { return std::asin (v); }
            template <typename T> inline T  atan_impl(const T v, real_type_tag) { return std::atan (v); }
            template <typename T> inline T  ceil_impl(const T v, real_type_tag) { return std::ceil (v); }
            template <typename T> inline T   cos_impl(const T v, real_type_tag) { return std::cos  (v); }
            template <typename T> inline T  cosh_impl(const T v, real_type_tag) { return std::cosh (v); }
            template <typename T> inline T   exp_impl(const T v, real_type_tag) { return std::exp  (v); }
            template <typename T> inline T floor_impl(const T v, real_type_tag) { return std::floor(v); }
            template <typename T> inline T   log_impl(const T v, real_type_tag) { return std::log  (v); }
            template <typename T> inline T log10_impl(const T v, real_type_tag) { return std::log10(v); }
            template <typename T> inline T  log2_impl(const T v, real_type_tag) { return std::log(v)/T(numeric::constant::log2); }
            template <typename T> inline T   neg_impl(const T v, real_type_tag) { return -v;            }
            template <typename T> inline T   pos_impl(const T v, real_type_tag) { return +v;            }
            template <typename T> inline T   sin_impl(const T v, real_type_tag) { return std::sin  (v); }
            template <typename T> inline T  sinh_impl(const T v, real_type_tag) { return std::sinh (v); }
            template <typename T> inline T  sqrt_impl(const T v, real_type_tag) { return std::sqrt (v); }
            template <typename T> inline T   tan_impl(const T v, real_type_tag) { return std::tan  (v); }
            template <typename T> inline T  tanh_impl(const T v, real_type_tag) { return std::tanh (v); }
            template <typename T> inline T   cot_impl(const T v, real_type_tag) { return T(1) / std::tan(v); }
            template <typename T> inline T   sec_impl(const T v, real_type_tag) { return T(1) / std::cos(v); }
            template <typename T> inline T   csc_impl(const T v, real_type_tag) { return T(1) / std::sin(v); }
            template <typename T> inline T   r2d_impl(const T v, real_type_tag) { return (v * T(numeric::constant::_180_pi)); }
            template <typename T> inline T   d2r_impl(const T v, real_type_tag) { return (v * T(numeric::constant::pi_180));  }
            template <typename T> inline T   d2g_impl(const T v, real_type_tag) { return (v * T(10.0/9.0)); }
            template <typename T> inline T   g2d_impl(const T v, real_type_tag) { return (v * T(9.0/10.0)); }
            template <typename T> inline T  notl_impl(const T v, real_type_tag) { return (std::not_equal_to<T>()(T(0),v) ? T(0) : T(1)); }
            template <typename T> inline T  frac_impl(const T v, real_type_tag) { return (v - trunc_impl(v,real_type_tag())); }

            template <typename T> inline T   const_pi_impl(real_type_tag) { return T(numeric::constant::pi);            }
            template <typename T> inline T    const_e_impl(real_type_tag) { return T(numeric::constant::e);             }
            template <typename T> inline T const_qnan_impl(real_type_tag) { return std::numeric_limits<T>::quiet_NaN(); }

            template <typename T> inline T   abs_impl(const T v, int_type_tag) { return ((v >= T(0)) ? v : -v); }
            template <typename T> inline T   exp_impl(const T v, int_type_tag) { return std::exp  (v); }
            template <typename T> inline T   log_impl(const T v, int_type_tag) { return std::log  (v); }
            template <typename T> inline T log10_impl(const T v, int_type_tag) { return std::log10(v); }
            template <typename T> inline T  log2_impl(const T v, int_type_tag) { return std::log(v)/T(numeric::constant::log2); }
            template <typename T> inline T   neg_impl(const T v, int_type_tag) { return -v;            }
            template <typename T> inline T   pos_impl(const T v, int_type_tag) { return +v;            }
            template <typename T> inline T  ceil_impl(const T v, int_type_tag) { return v;             }
            template <typename T> inline T floor_impl(const T v, int_type_tag) { return v;             }
            template <typename T> inline T round_impl(const T v, int_type_tag) { return v;             }
            template <typename T> inline T  notl_impl(const T v, int_type_tag) { return !v;            }
            template <typename T> inline T  sqrt_impl(const T v, int_type_tag) { return std::sqrt (v); }
            template <typename T> inline T  frac_impl(const T  , int_type_tag) { return T(0);          }
            template <typename T> inline T trunc_impl(const T v, int_type_tag) { return v;             }
            template <typename T> inline T  acos_impl(const T  , int_type_tag) { return std::numeric_limits<T>::quiet_NaN(); }
            template <typename T> inline T acosh_impl(const T  , int_type_tag) { return std::numeric_limits<T>::quiet_NaN(); }
            template <typename T> inline T  asin_impl(const T  , int_type_tag) { return std::numeric_limits<T>::quiet_NaN(); }
            template <typename T> inline T asinh_impl(const T  , int_type_tag) { return std::numeric_limits<T>::quiet_NaN(); }
            template <typename T> inline T  atan_impl(const T  , int_type_tag) { return std::numeric_limits<T>::quiet_NaN(); }
            template <typename T> inline T atanh_impl(const T  , int_type_tag) { return std::numeric_limits<T>::quiet_NaN(); }
            template <typename T> inline T   cos_impl(const T  , int_type_tag) { return std::numeric_limits<T>::quiet_NaN(); }
            template <typename T> inline T  cosh_impl(const T  , int_type_tag) { return std::numeric_limits<T>::quiet_NaN(); }
            template <typename T> inline T   sin_impl(const T  , int_type_tag) { return std::numeric_limits<T>::quiet_NaN(); }
            template <typename T> inline T  sinh_impl(const T  , int_type_tag) { return std::numeric_limits<T>::quiet_NaN(); }
            template <typename T> inline T   tan_impl(const T  , int_type_tag) { return std::numeric_limits<T>::quiet_NaN(); }
            template <typename T> inline T  tanh_impl(const T  , int_type_tag) { return std::numeric_limits<T>::quiet_NaN(); }
            template <typename T> inline T   cot_impl(const T  , int_type_tag) { return std::numeric_limits<T>::quiet_NaN(); }
            template <typename T> inline T   sec_impl(const T  , int_type_tag) { return std::numeric_limits<T>::quiet_NaN(); }
            template <typename T> inline T   csc_impl(const T  , int_type_tag) { return std::numeric_limits<T>::quiet_NaN(); }

            template <typename T>
            inline bool is_integer_impl(const T& v, real_type_tag)
            {
               return std::equal_to<T>()(T(0),std::fmod(v,T(1)));
            }

            template <typename T>
            inline bool is_integer_impl(const T&, int_type_tag)
            {
               return true;
            }
         }

         template <typename Type>
         struct numeric_info { enum { length = 0, size = 32, bound_length = 0, min_exp = 0, max_exp = 0 }; };

         template <> struct numeric_info<int        > { enum { length = 10, size = 16, bound_length = 9 }; };
         template <> struct numeric_info<float      > { enum { min_exp =  -38, max_exp =  +38 }; };
         template <> struct numeric_info<double     > { enum { min_exp = -308, max_exp = +308 }; };
         template <> struct numeric_info<long double> { enum { min_exp = -308, max_exp = +308 }; };

         template <typename T>
         inline int to_int32(const T v)
         {
            const typename details::number_type<T>::type num_type;
            return to_int32_impl(v, num_type);
         }

         template <typename T>
         inline _int64_t to_int64(const T v)
         {
            const typename details::number_type<T>::type num_type;
            return to_int64_impl(v, num_type);
         }

         template <typename T>
         inline _uint64_t to_uint64(const T v)
         {
            const typename details::number_type<T>::type num_type;
            return to_uint64_impl(v, num_type);
         }

         template <typename T>
         inline bool is_nan(const T v)
         {
            const typename details::number_type<T>::type num_type;
            return is_nan_impl(v, num_type);
         }

         template <typename T>
         inline T min(const T v0, const T v1)
         {
            const typename details::number_type<T>::type num_type;
            return min_impl(v0, v1, num_type);
         }

         template <typename T>
         inline T max(const T v0, const T v1)
         {
            const typename details::number_type<T>::type num_type;
            return max_impl(v0, v1, num_type);
         }

         template <typename T>
         inline T equal(const T v0, const T v1)
         {
            const typename details::number_type<T>::type num_type;
            return equal_impl(v0, v1, num_type);
         }

         template <typename T>
         inline T nequal(const T v0, const T v1)
         {
            const typename details::number_type<T>::type num_type;
            return nequal_impl(v0, v1, num_type);
         }

         template <typename T>
         inline T modulus(const T v0, const T v1)
         {
            const typename details::number_type<T>::type num_type;
            return modulus_impl(v0, v1, num_type);
         }

         template <typename T>
         inline T pow(const T v0, const T v1)
         {
            const typename details::number_type<T>::type num_type;
            return pow_impl(v0, v1, num_type);
         }

         template <typename T>
         inline T logn(const T v0, const T v1)
         {
            const typename details::number_type<T>::type num_type;
            return logn_impl(v0, v1, num_type);
         }

         template <typename T>
         inline T root(const T v0, const T v1)
         {
            const typename details::number_type<T>::type num_type;
            return root_impl(v0, v1, num_type);
         }

         template <typename T>
         inline T roundn(const T v0, const T v1)
         {
            const typename details::number_type<T>::type num_type;
            return roundn_impl(v0, v1, num_type);
         }

         template <typename T>
         inline T hypot(const T v0, const T v1)
         {
            const typename details::number_type<T>::type num_type;
            return hypot_impl(v0, v1, num_type);
         }

         template <typename T>
         inline T atan2(const T v0, const T v1)
         {
            const typename details::number_type<T>::type num_type;
            return atan2_impl(v0, v1, num_type);
         }

         template <typename T>
         inline T shr(const T v0, const T v1)
         {
            const typename details::number_type<T>::type num_type;
            return shr_impl(v0, v1, num_type);
         }

         template <typename T>
         inline T shl(const T v0, const T v1)
         {
            const typename details::number_type<T>::type num_type;
            return shl_impl(v0, v1, num_type);
         }

         template <typename T>
         inline T and_opr(const T v0, const T v1)
         {
            const typename details::number_type<T>::type num_type;
            return and_impl(v0, v1, num_type);
         }

         template <typename T>
         inline T nand_opr(const T v0, const T v1)
         {
            const typename details::number_type<T>::type num_type;
            return nand_impl(v0, v1, num_type);
         }

         template <typename T>
         inline T or_opr(const T v0, const T v1)
         {
            const typename details::number_type<T>::type num_type;
            return or_impl(v0, v1, num_type);
         }

         template <typename T>
         inline T nor_opr(const T v0, const T v1)
         {
            const typename details::number_type<T>::type num_type;
            return nor_impl(v0, v1, num_type);
         }

         template <typename T>
         inline T xor_opr(const T v0, const T v1)
         {
            const typename details::number_type<T>::type num_type;
            return xor_impl(v0, v1, num_type);
         }

         template <typename T>
         inline T xnor_opr(const T v0, const T v1)
         {
            const typename details::number_type<T>::type num_type;
            return xnor_impl(v0, v1, num_type);
         }

         template <typename T>
         inline bool is_integer(const T v)
         {
            const typename details::number_type<T>::type num_type;
            return is_integer_impl(v, num_type);
         }

         template <typename T, unsigned int N>
         struct fast_exp
         {
            static inline T result(T v)
            {
               unsigned int k = N;
               T l = T(1);

               while (k)
               {
                  if (1 == (k % 2))
                  {
                     l *= v;
                     --k;
                  }

                  v *= v;
                  k /= 2;
               }

               return l;
            }
         };

         template <typename T> struct fast_exp<T,10> { static inline T result(const T v) { T v_5 = fast_exp<T,5>::result(v); return v_5 * v_5; } };
         template <typename T> struct fast_exp<T, 9> { static inline T result(const T v) { return fast_exp<T,8>::result(v) * v; } };
         template <typename T> struct fast_exp<T, 8> { static inline T result(const T v) { T v_4 = fast_exp<T,4>::result(v); return v_4 * v_4; } };
         template <typename T> struct fast_exp<T, 7> { static inline T result(const T v) { return fast_exp<T,6>::result(v) * v; } };
         template <typename T> struct fast_exp<T, 6> { static inline T result(const T v) { T v_3 = fast_exp<T,3>::result(v); return v_3 * v_3; } };
         template <typename T> struct fast_exp<T, 5> { static inline T result(const T v) { return fast_exp<T,4>::result(v) * v; } };
         template <typename T> struct fast_exp<T, 4> { static inline T result(const T v) { T v_2 = v * v; return v_2 * v_2; } };
         template <typename T> struct fast_exp<T, 3> { static inline T result(const T v) { return v * v * v; } };
         template <typename T> struct fast_exp<T, 2> { static inline T result(const T v) { return v * v;     } };
         template <typename T> struct fast_exp<T, 1> { static inline T result(const T v) { return v;         } };
         template <typename T> struct fast_exp<T, 0> { static inline T result(const T  ) { return T(1);      } };

         #define exprtk_define_unary_function(FunctionName)        \
         template <typename T>                                     \
         inline T FunctionName (const T v)                         \
         {                                                         \
            const typename details::number_type<T>::type num_type; \
            return  FunctionName##_impl(v,num_type);               \
         }                                                         \

         exprtk_define_unary_function(abs  )
         exprtk_define_unary_function(acos )
         exprtk_define_unary_function(acosh)
         exprtk_define_unary_function(asin )
         exprtk_define_unary_function(asinh)
         exprtk_define_unary_function(atan )
         exprtk_define_unary_function(atanh)
         exprtk_define_unary_function(ceil )
         exprtk_define_unary_function(cos  )
         exprtk_define_unary_function(cosh )
         exprtk_define_unary_function(exp  )
         exprtk_define_unary_function(expm1)
         exprtk_define_unary_function(floor)
         exprtk_define_unary_function(log  )
         exprtk_define_unary_function(log10)
         exprtk_define_unary_function(log2 )
         exprtk_define_unary_function(log1p)
         exprtk_define_unary_function(neg  )
         exprtk_define_unary_function(pos  )
         exprtk_define_unary_function(round)
         exprtk_define_unary_function(sin  )
         exprtk_define_unary_function(sinc )
         exprtk_define_unary_function(sinh )
         exprtk_define_unary_function(sqrt )
         exprtk_define_unary_function(tan  )
         exprtk_define_unary_function(tanh )
         exprtk_define_unary_function(cot  )
         exprtk_define_unary_function(sec  )
         exprtk_define_unary_function(csc  )
         exprtk_define_unary_function(r2d  )
         exprtk_define_unary_function(d2r  )
         exprtk_define_unary_function(d2g  )
         exprtk_define_unary_function(g2d  )
         exprtk_define_unary_function(notl )
         exprtk_define_unary_function(sgn  )
         exprtk_define_unary_function(erf  )
         exprtk_define_unary_function(erfc )
         exprtk_define_unary_function(ncdf )
         exprtk_define_unary_function(frac )
         exprtk_define_unary_function(trunc)
         #undef exprtk_define_unary_function
      }

      template <typename T>
      inline T compute_pow10(T d, const int exponent)
      {
         static const double fract10[] =
         {
            0.0,
            1.0E+001, 1.0E+002, 1.0E+003, 1.0E+004, 1.0E+005, 1.0E+006, 1.0E+007, 1.0E+008, 1.0E+009, 1.0E+010,
            1.0E+011, 1.0E+012, 1.0E+013, 1.0E+014, 1.0E+015, 1.0E+016, 1.0E+017, 1.0E+018, 1.0E+019, 1.0E+020,
            1.0E+021, 1.0E+022, 1.0E+023, 1.0E+024, 1.0E+025, 1.0E+026, 1.0E+027, 1.0E+028, 1.0E+029, 1.0E+030,
            1.0E+031, 1.0E+032, 1.0E+033, 1.0E+034, 1.0E+035, 1.0E+036, 1.0E+037, 1.0E+038, 1.0E+039, 1.0E+040,
            1.0E+041, 1.0E+042, 1.0E+043, 1.0E+044, 1.0E+045, 1.0E+046, 1.0E+047, 1.0E+048, 1.0E+049, 1.0E+050,
            1.0E+051, 1.0E+052, 1.0E+053, 1.0E+054, 1.0E+055, 1.0E+056, 1.0E+057, 1.0E+058, 1.0E+059, 1.0E+060,
            1.0E+061, 1.0E+062, 1.0E+063, 1.0E+064, 1.0E+065, 1.0E+066, 1.0E+067, 1.0E+068, 1.0E+069, 1.0E+070,
            1.0E+071, 1.0E+072, 1.0E+073, 1.0E+074, 1.0E+075, 1.0E+076, 1.0E+077, 1.0E+078, 1.0E+079, 1.0E+080,
            1.0E+081, 1.0E+082, 1.0E+083, 1.0E+084, 1.0E+085, 1.0E+086, 1.0E+087, 1.0E+088, 1.0E+089, 1.0E+090,
            1.0E+091, 1.0E+092, 1.0E+093, 1.0E+094, 1.0E+095, 1.0E+096, 1.0E+097, 1.0E+098, 1.0E+099, 1.0E+100,
            1.0E+101, 1.0E+102, 1.0E+103, 1.0E+104, 1.0E+105, 1.0E+106, 1.0E+107, 1.0E+108, 1.0E+109, 1.0E+110,
            1.0E+111, 1.0E+112, 1.0E+113, 1.0E+114, 1.0E+115, 1.0E+116, 1.0E+117, 1.0E+118, 1.0E+119, 1.0E+120,
            1.0E+121, 1.0E+122, 1.0E+123, 1.0E+124, 1.0E+125, 1.0E+126, 1.0E+127, 1.0E+128, 1.0E+129, 1.0E+130,
            1.0E+131, 1.0E+132, 1.0E+133, 1.0E+134, 1.0E+135, 1.0E+136, 1.0E+137, 1.0E+138, 1.0E+139, 1.0E+140,
            1.0E+141, 1.0E+142, 1.0E+143, 1.0E+144, 1.0E+145, 1.0E+146, 1.0E+147, 1.0E+148, 1.0E+149, 1.0E+150,
            1.0E+151, 1.0E+152, 1.0E+153, 1.0E+154, 1.0E+155, 1.0E+156, 1.0E+157, 1.0E+158, 1.0E+159, 1.0E+160,
            1.0E+161, 1.0E+162, 1.0E+163, 1.0E+164, 1.0E+165, 1.0E+166, 1.0E+167, 1.0E+168, 1.0E+169, 1.0E+170,
            1.0E+171, 1.0E+172, 1.0E+173, 1.0E+174, 1.0E+175, 1.0E+176, 1.0E+177, 1.0E+178, 1.0E+179, 1.0E+180,
            1.0E+181, 1.0E+182, 1.0E+183, 1.0E+184, 1.0E+185, 1.0E+186, 1.0E+187, 1.0E+188, 1.0E+189, 1.0E+190,
            1.0E+191, 1.0E+192, 1.0E+193, 1.0E+194, 1.0E+195, 1.0E+196, 1.0E+197, 1.0E+198, 1.0E+199, 1.0E+200,
            1.0E+201, 1.0E+202, 1.0E+203, 1.0E+204, 1.0E+205, 1.0E+206, 1.0E+207, 1.0E+208, 1.0E+209, 1.0E+210,
            1.0E+211, 1.0E+212, 1.0E+213, 1.0E+214, 1.0E+215, 1.0E+216, 1.0E+217, 1.0E+218, 1.0E+219, 1.0E+220,
            1.0E+221, 1.0E+222, 1.0E+223, 1.0E+224, 1.0E+225, 1.0E+226, 1.0E+227, 1.0E+228, 1.0E+229, 1.0E+230,
            1.0E+231, 1.0E+232, 1.0E+233, 1.0E+234, 1.0E+235, 1.0E+236, 1.0E+237, 1.0E+238, 1.0E+239, 1.0E+240,
            1.0E+241, 1.0E+242, 1.0E+243, 1.0E+244, 1.0E+245, 1.0E+246, 1.0E+247, 1.0E+248, 1.0E+249, 1.0E+250,
            1.0E+251, 1.0E+252, 1.0E+253, 1.0E+254, 1.0E+255, 1.0E+256, 1.0E+257, 1.0E+258, 1.0E+259, 1.0E+260,
            1.0E+261, 1.0E+262, 1.0E+263, 1.0E+264, 1.0E+265, 1.0E+266, 1.0E+267, 1.0E+268, 1.0E+269, 1.0E+270,
            1.0E+271, 1.0E+272, 1.0E+273, 1.0E+274, 1.0E+275, 1.0E+276, 1.0E+277, 1.0E+278, 1.0E+279, 1.0E+280,
            1.0E+281, 1.0E+282, 1.0E+283, 1.0E+284, 1.0E+285, 1.0E+286, 1.0E+287, 1.0E+288, 1.0E+289, 1.0E+290,
            1.0E+291, 1.0E+292, 1.0E+293, 1.0E+294, 1.0E+295, 1.0E+296, 1.0E+297, 1.0E+298, 1.0E+299, 1.0E+300,
            1.0E+301, 1.0E+302, 1.0E+303, 1.0E+304, 1.0E+305, 1.0E+306, 1.0E+307, 1.0E+308
         };

         static const int fract10_size = static_cast<int>(sizeof(fract10) / sizeof(double));

         const int e = std::abs(exponent);

         if (exponent >= std::numeric_limits<T>::min_exponent10)
         {
            if (e < fract10_size)
            {
               if (exponent > 0)
                  return T(d * fract10[e]);
               else
                  return T(d / fract10[e]);
            }
            else
               return T(d * std::pow(10.0, 10.0 * exponent));
         }
         else
         {
                     d /= T(fract10[           -std::numeric_limits<T>::min_exponent10]);
            return T(d /    fract10[-exponent + std::numeric_limits<T>::min_exponent10]);
         }
      }

      template <typename Iterator, typename T>
      inline bool string_to_type_converter_impl_ref(Iterator& itr, const Iterator end, T& result)
      {
         if (itr == end)
            return false;

         const bool negative = ('-' == (*itr));

         if (negative || ('+' == (*itr)))
         {
            if (end == ++itr)
               return false;
         }

         static const uchar_t zero = static_cast<uchar_t>('0');

         while ((end != itr) && (zero == (*itr))) ++itr;

         bool return_result = true;
         unsigned int digit = 0;
         const std::size_t length = static_cast<std::size_t>(std::distance(itr,end));

         if (length <= 4)
         {
            switch (length)
            {
               #ifdef exprtk_use_lut

               #define exprtk_process_digit                          \
               if ((digit = details::digit_table[(int)*itr++]) < 10) \
                  result = result * 10 + (digit);                    \
               else                                                  \
               {                                                     \
                  return_result = false;                             \
                  break;                                             \
               }                                                     \
               exprtk_fallthrough                                    \

               #else

               #define exprtk_process_digit        \
               if ((digit = (*itr++ - zero)) < 10) \
                  result = result * T(10) + digit; \
               else                                \
               {                                   \
                  return_result = false;           \
                  break;                           \
               }                                   \
               exprtk_fallthrough                  \

               #endif

               case 4 : exprtk_process_digit
               case 3 : exprtk_process_digit
               case 2 : exprtk_process_digit
               case 1 : if ((digit = (*itr - zero))>= 10)
                        {
                           digit = 0;
                           return_result = false;
                        }

               #undef exprtk_process_digit
            }
         }
         else
            return_result = false;

         if (length && return_result)
         {
            result = result * 10 + static_cast<T>(digit);
            ++itr;
         }

         result = negative ? -result : result;
         return return_result;
      }

      template <typename Iterator, typename T>
      static inline bool parse_nan(Iterator& itr, const Iterator end, T& t)
      {
         typedef typename std::iterator_traits<Iterator>::value_type type;

         static const std::size_t nan_length = 3;

         if (std::distance(itr,end) != static_cast<int>(nan_length))
            return false;

         if (static_cast<type>('n') == (*itr))
         {
            if (
                 (static_cast<type>('a') != *(itr + 1)) ||
                 (static_cast<type>('n') != *(itr + 2))
               )
            {
               return false;
            }
         }
         else if (
                   (static_cast<type>('A') != *(itr + 1)) ||
                   (static_cast<type>('N') != *(itr + 2))
                 )
         {
            return false;
         }

         t = std::numeric_limits<T>::quiet_NaN();

         return true;
      }

      template <typename Iterator, typename T>
      static inline bool parse_inf(Iterator& itr, const Iterator end, T& t, const bool negative)
      {
         static const char_t inf_uc[] = "INFINITY";
         static const char_t inf_lc[] = "infinity";
         static const std::size_t inf_length = 8;

         const std::size_t length = static_cast<std::size_t>(std::distance(itr,end));

         if ((3 != length) && (inf_length != length))
            return false;

         char_cptr inf_itr = ('i' == (*itr)) ? inf_lc : inf_uc;

         while (end != itr)
         {
            if (*inf_itr == static_cast<char_t>(*itr))
            {
               ++itr;
               ++inf_itr;
               continue;
            }
            else
               return false;
         }

         if (negative)
            t = -std::numeric_limits<T>::infinity();
         else
            t =  std::numeric_limits<T>::infinity();

         return true;
      }

      template <typename T>
      inline bool valid_exponent(const int exponent, numeric::details::real_type_tag)
      {
         using namespace details::numeric;
         return (numeric_info<T>::min_exp <= exponent) && (exponent <= numeric_info<T>::max_exp);
      }

      template <typename Iterator, typename T>
      inline bool string_to_real(Iterator& itr_external, const Iterator end, T& t, numeric::details::real_type_tag)
      {
         if (end == itr_external) return false;

         Iterator itr = itr_external;

         T d = T(0);

         const bool negative = ('-' == (*itr));

         if (negative || '+' == (*itr))
         {
            if (end == ++itr)
               return false;
         }

         bool instate = false;

         static const char_t zero = static_cast<uchar_t>('0');

         #define parse_digit_1(d)          \
         if ((digit = (*itr - zero)) < 10) \
            { d = d * T(10) + digit; }     \
         else                              \
            { break; }                     \
         if (end == ++itr) break;          \

         #define parse_digit_2(d)          \
         if ((digit = (*itr - zero)) < 10) \
            { d = d * T(10) + digit; }     \
         else                              \
            { break; }                     \
            ++itr;                         \

         if ('.' != (*itr))
         {
            const Iterator curr = itr;

            while ((end != itr) && (zero == (*itr))) ++itr;

            while (end != itr)
            {
               unsigned int digit;
               parse_digit_1(d)
               parse_digit_1(d)
               parse_digit_2(d)
            }

            if (curr != itr) instate = true;
         }

         int exponent = 0;

         if (end != itr)
         {
            if ('.' == (*itr))
            {
               const Iterator curr = ++itr;
               T tmp_d = T(0);

               while (end != itr)
               {
                  unsigned int digit;
                  parse_digit_1(tmp_d)
                  parse_digit_1(tmp_d)
                  parse_digit_2(tmp_d)
               }

               if (curr != itr)
               {
                  instate = true;

                  const int frac_exponent = static_cast<int>(-std::distance(curr, itr));

                  if (!valid_exponent<T>(frac_exponent, numeric::details::real_type_tag()))
                     return false;

                  d += compute_pow10(tmp_d, frac_exponent);
               }

               #undef parse_digit_1
               #undef parse_digit_2
            }

            if (end != itr)
            {
               typename std::iterator_traits<Iterator>::value_type c = (*itr);

               if (('e' == c) || ('E' == c))
               {
                  int exp = 0;

                  if (!details::string_to_type_converter_impl_ref(++itr, end, exp))
                  {
                     if (end == itr)
                        return false;
                     else
                        c = (*itr);
                  }

                  exponent += exp;
               }

               if (end != itr)
               {
                  if (('f' == c) || ('F' == c) || ('l' == c) || ('L' == c))
                     ++itr;
                  else if ('#' == c)
                  {
                     if (end == ++itr)
                        return false;
                     else if (('I' <= (*itr)) && ((*itr) <= 'n'))
                     {
                        if (('i' == (*itr)) || ('I' == (*itr)))
                        {
                           return parse_inf(itr, end, t, negative);
                        }
                        else if (('n' == (*itr)) || ('N' == (*itr)))
                        {
                           return parse_nan(itr, end, t);
                        }
                        else
                           return false;
                     }
                     else
                        return false;
                  }
                  else if (('I' <= (*itr)) && ((*itr) <= 'n'))
                  {
                     if (('i' == (*itr)) || ('I' == (*itr)))
                     {
                        return parse_inf(itr, end, t, negative);
                     }
                     else if (('n' == (*itr)) || ('N' == (*itr)))
                     {
                        return parse_nan(itr, end, t);
                     }
                     else
                        return false;
                  }
                  else
                     return false;
               }
            }
         }

         if ((end != itr) || (!instate))
            return false;
         else if (!valid_exponent<T>(exponent, numeric::details::real_type_tag()))
            return false;
         else if (exponent)
            d = compute_pow10(d,exponent);

         t = static_cast<T>((negative) ? -d : d);
         return true;
      }

      template <typename T>
      inline bool string_to_real(const std::string& s, T& t)
      {
         const typename numeric::details::number_type<T>::type num_type;

         char_cptr begin = s.data();
         char_cptr end   = s.data() + s.size();

         return string_to_real(begin, end, t, num_type);
      }

      template <typename T>
      struct functor_t
      {
         /*
            Note: The following definitions for Type, may require tweaking
                  based on the compiler and target architecture. The benchmark
                  should provide enough information to make the right choice.
         */
         //typedef T Type;
         //typedef const T Type;
         typedef const T& Type;
         typedef       T& RefType;
         typedef T (*qfunc_t)(Type t0, Type t1, Type t2, Type t3);
         typedef T (*tfunc_t)(Type t0, Type t1, Type t2);
         typedef T (*bfunc_t)(Type t0, Type t1);
         typedef T (*ufunc_t)(Type t0);
      };

   } // namespace details

   struct loop_runtime_check
   {
      enum loop_types
      {
         e_invalid           = 0,
         e_for_loop          = 1,
         e_while_loop        = 2,
         e_repeat_until_loop = 4,
         e_all_loops         = 7
      };

      enum violation_type
      {
          e_unknown         = 0,
          e_iteration_count = 1,
          e_timeout         = 2
      };

      loop_types loop_set;

      loop_runtime_check()
      : loop_set(e_invalid)
      , max_loop_iterations(0)
      {}

      details::_uint64_t max_loop_iterations;

      struct violation_context
      {
         loop_types loop;
         violation_type violation;
         details::_uint64_t iteration_count;
      };

      virtual bool check()
      {
         return true;
      }

      virtual void handle_runtime_violation(const violation_context&)
      {
         throw std::runtime_error("ExprTk Loop runtime violation.");
      }

      virtual ~loop_runtime_check()
      {}
   };

   typedef loop_runtime_check* loop_runtime_check_ptr;

   struct vector_access_runtime_check
   {
      struct violation_context
      {
         void* base_ptr;
         void* end_ptr;
         void* access_ptr;
         std::size_t type_size;
      };

      virtual ~vector_access_runtime_check()
      {}

      virtual bool handle_runtime_violation(violation_context& /*context*/)
      {
         throw std::runtime_error("ExprTk runtime vector access violation.");
         #if !defined(_MSC_VER) && !defined(__NVCOMPILER)
         return false;
         #endif
      }
   };

   typedef vector_access_runtime_check* vector_access_runtime_check_ptr;

   struct assert_check
   {
      struct assert_context
      {
         std::string condition;
         std::string message;
         std::string id;
         std::size_t offet;
      };

      virtual ~assert_check()
      {}

      virtual void handle_assert(const assert_context& /*context*/)
      {}
   };

   typedef assert_check* assert_check_ptr;

   struct compilation_check
   {
      struct compilation_context
      {
         std::string error_message;
      };

      virtual bool continue_compilation(compilation_context& /*context*/) = 0;

      virtual ~compilation_check()
      {}
   };

   typedef compilation_check* compilation_check_ptr;

   namespace lexer
   {
      struct token
      {
         enum token_type
         {
            e_none        =   0, e_error       =   1, e_err_symbol  =   2,
            e_err_number  =   3, e_err_string  =   4, e_err_sfunc   =   5,
            e_eof         =   6, e_number      =   7, e_symbol      =   8,
            e_string      =   9, e_assign      =  10, e_addass      =  11,
            e_subass      =  12, e_mulass      =  13, e_divass      =  14,
            e_modass      =  15, e_shr         =  16, e_shl         =  17,
            e_lte         =  18, e_ne          =  19, e_gte         =  20,
            e_swap        =  21, e_lt          = '<', e_gt          = '>',
            e_eq          = '=', e_rbracket    = ')', e_lbracket    = '(',
            e_rsqrbracket = ']', e_lsqrbracket = '[', e_rcrlbracket = '}',
            e_lcrlbracket = '{', e_comma       = ',', e_add         = '+',
            e_sub         = '-', e_div         = '/', e_mul         = '*',
            e_mod         = '%', e_pow         = '^', e_colon       = ':',
            e_ternary     = '?'
         };

         token()
         : type(e_none)
         , value("")
         , position(std::numeric_limits<std::size_t>::max())
         {}

         void clear()
         {
            type     = e_none;
            value    = "";
            position = std::numeric_limits<std::size_t>::max();
         }

         template <typename Iterator>
         inline token& set_operator(const token_type tt,
                                    const Iterator begin, const Iterator end,
                                    const Iterator base_begin = Iterator(0))
         {
            type = tt;
            value.assign(begin,end);
            if (base_begin)
               position = static_cast<std::size_t>(std::distance(base_begin,begin));
            return (*this);
         }

         template <typename Iterator>
         inline token& set_symbol(const Iterator begin, const Iterator end, const Iterator base_begin = Iterator(0))
         {
            type = e_symbol;
            value.assign(begin,end);
            if (base_begin)
               position = static_cast<std::size_t>(std::distance(base_begin,begin));
            return (*this);
         }

         template <typename Iterator>
         inline token& set_numeric(const Iterator begin, const Iterator end, const Iterator base_begin = Iterator(0))
         {
            type = e_number;
            value.assign(begin,end);
            if (base_begin)
               position = static_cast<std::size_t>(std::distance(base_begin,begin));
            return (*this);
         }

         template <typename Iterator>
         inline token& set_string(const Iterator begin, const Iterator end, const Iterator base_begin = Iterator(0))
         {
            type = e_string;
            value.assign(begin,end);
            if (base_begin)
               position = static_cast<std::size_t>(std::distance(base_begin,begin));
            return (*this);
         }

         inline token& set_string(const std::string& s, const std::size_t p)
         {
            type     = e_string;
            value    = s;
            position = p;
            return (*this);
         }

         template <typename Iterator>
         inline token& set_error(const token_type et,
                                 const Iterator begin, const Iterator end,
                                 const Iterator base_begin = Iterator(0))
         {
            if (
                 (e_error      == et) ||
                 (e_err_symbol == et) ||
                 (e_err_number == et) ||
                 (e_err_string == et) ||
                 (e_err_sfunc  == et)
               )
            {
               type = et;
            }
            else
               type = e_error;

            value.assign(begin,end);

            if (base_begin)
               position = static_cast<std::size_t>(std::distance(base_begin,begin));

            return (*this);
         }

         static inline std::string to_str(token_type t)
         {
            switch (t)
            {
               case e_none        : return "NONE";
               case e_error       : return "ERROR";
               case e_err_symbol  : return "ERROR_SYMBOL";
               case e_err_number  : return "ERROR_NUMBER";
               case e_err_string  : return "ERROR_STRING";
               case e_eof         : return "EOF";
               case e_number      : return "NUMBER";
               case e_symbol      : return "SYMBOL";
               case e_string      : return "STRING";
               case e_assign      : return ":=";
               case e_addass      : return "+=";
               case e_subass      : return "-=";
               case e_mulass      : return "*=";
               case e_divass      : return "/=";
               case e_modass      : return "%=";
               case e_shr         : return ">>";
               case e_shl         : return "<<";
               case e_lte         : return "<=";
               case e_ne          : return "!=";
               case e_gte         : return ">=";
               case e_lt          : return "<";
               case e_gt          : return ">";
               case e_eq          : return "=";
               case e_rbracket    : return ")";
               case e_lbracket    : return "(";
               case e_rsqrbracket : return "]";
               case e_lsqrbracket : return "[";
               case e_rcrlbracket : return "}";
               case e_lcrlbracket : return "{";
               case e_comma       : return ",";
               case e_add         : return "+";
               case e_sub         : return "-";
               case e_div         : return "/";
               case e_mul         : return "*";
               case e_mod         : return "%";
               case e_pow         : return "^";
               case e_colon       : return ":";
               case e_ternary     : return "?";
               case e_swap        : return "<=>";
               default            : return "UNKNOWN";
            }
         }

         static inline std::string seperator_to_str(const token_type t)
         {
            switch (t)
            {
               case e_comma : return ",";
               case e_colon : return ":";
               case e_eof   : return ";";
               default      : return "UNKNOWN";
            }

            #if !defined(_MSC_VER) && !defined(__NVCOMPILER)
            return "UNKNOWN";
            #endif
         }

         inline bool is_error() const
         {
            return (e_error      == type) ||
                   (e_err_symbol == type) ||
                   (e_err_number == type) ||
                   (e_err_string == type) ||
                   (e_err_sfunc  == type) ;
         }

         token_type type;
         std::string value;
         std::size_t position;
      };

      class generator
      {
      public:

         typedef token token_t;
         typedef std::vector<token_t> token_list_t;
         typedef token_list_t::iterator token_list_itr_t;
         typedef details::char_t char_t;

         generator()
         : base_itr_(0)
         , s_itr_   (0)
         , s_end_   (0)
         {
            clear();
         }

         inline void clear()
         {
            base_itr_ = 0;
            s_itr_    = 0;
            s_end_    = 0;
            token_list_.clear();
            token_itr_ = token_list_.end();
            store_token_itr_ = token_list_.end();
         }

         inline bool process(const std::string& str)
         {
            base_itr_ = str.data();
            s_itr_    = str.data();
            s_end_    = str.data() + str.size();

            eof_token_.set_operator(token_t::e_eof, s_end_, s_end_, base_itr_);
            token_list_.clear();

            while (!is_end(s_itr_))
            {
               scan_token();

               if (!token_list_.empty() && token_list_.back().is_error())
                  return false;
            }

            return true;
         }

         inline bool empty() const
         {
            return token_list_.empty();
         }

         inline std::size_t size() const
         {
            return token_list_.size();
         }

         inline void begin()
         {
            token_itr_ = token_list_.begin();
            store_token_itr_ = token_list_.begin();
         }

         inline void store()
         {
            store_token_itr_ = token_itr_;
         }

         inline void restore()
         {
            token_itr_ = store_token_itr_;
         }

         inline token_t& next_token()
         {
            if (token_list_.end() != token_itr_)
            {
               return *token_itr_++;
            }
            else
               return eof_token_;
         }

         inline token_t& peek_next_token()
         {
            if (token_list_.end() != token_itr_)
            {
               return *token_itr_;
            }
            else
               return eof_token_;
         }

         inline token_t& operator[](const std::size_t& index)
         {
            if (index < token_list_.size())
            {
               return token_list_[index];
            }
            else
               return eof_token_;
         }

         inline token_t operator[](const std::size_t& index) const
         {
            if (index < token_list_.size())
            {
               return token_list_[index];
            }
            else
               return eof_token_;
         }

         inline bool finished() const
         {
            return (token_list_.end() == token_itr_);
         }

         inline void insert_front(token_t::token_type tk_type)
         {
            if (
                 !token_list_.empty() &&
                 (token_list_.end() != token_itr_)
               )
            {
               token_t t = *token_itr_;

               t.type     = tk_type;
               token_itr_ = token_list_.insert(token_itr_,t);
            }
         }

         inline std::string substr(const std::size_t& begin, const std::size_t& end) const
         {
            const details::char_cptr begin_itr = ((base_itr_ + begin) < s_end_) ? (base_itr_ + begin) : s_end_;
            const details::char_cptr end_itr   = ((base_itr_ + end  ) < s_end_) ? (base_itr_ + end  ) : s_end_;

            return std::string(begin_itr,end_itr);
         }

         inline std::string remaining() const
         {
            if (finished())
               return "";
            else if (token_list_.begin() != token_itr_)
               return std::string(base_itr_ + (token_itr_ - 1)->position, s_end_);
            else
               return std::string(base_itr_ + token_itr_->position, s_end_);
         }

      private:

         inline bool is_end(details::char_cptr itr) const
         {
            return (s_end_ == itr);
         }

         #ifndef exprtk_disable_comments
         inline bool is_comment_start(details::char_cptr itr) const
         {
            const char_t c0 = *(itr + 0);
            const char_t c1 = *(itr + 1);

            if ('#' == c0)
               return true;
            else if (!is_end(itr + 1))
            {
               if (('/' == c0) && ('/' == c1)) return true;
               if (('/' == c0) && ('*' == c1)) return true;
            }
            return false;
         }
         #else
         inline bool is_comment_start(details::char_cptr) const
         {
            return false;
         }
         #endif

         inline void skip_whitespace()
         {
            while (!is_end(s_itr_) && details::is_whitespace(*s_itr_))
            {
               ++s_itr_;
            }
         }

         inline void skip_comments()
         {
            #ifndef exprtk_disable_comments
            // The following comment styles are supported:
            // 1. // .... \n
            // 2. #  .... \n
            // 3. /* .... */
            struct test
            {
               static inline bool comment_start(const char_t c0, const char_t c1, int& mode, int& incr)
               {
                  mode = 0;
                  if      ('#' == c0)    { mode = 1; incr = 1; }
                  else if ('/' == c0)
                  {
                     if      ('/' == c1) { mode = 1; incr = 2; }
                     else if ('*' == c1) { mode = 2; incr = 2; }
                  }
                  return (0 != mode);
               }

               static inline bool comment_end(const char_t c0, const char_t c1, int& mode)
               {
                  if (
                       ((1 == mode) && ('\n' == c0)) ||
                       ((2 == mode) && ( '*' == c0) && ('/' == c1))
                     )
                  {
                     mode = 0;
                     return true;
                  }
                  else
                     return false;
               }
            };

            int mode      = 0;
            int increment = 0;

            if (is_end(s_itr_))
               return;
            else if (!test::comment_start(*s_itr_, *(s_itr_ + 1), mode, increment))
               return;

            details::char_cptr cmt_start = s_itr_;

            s_itr_ += increment;

            while (!is_end(s_itr_))
            {
               if ((1 == mode) && test::comment_end(*s_itr_, 0, mode))
               {
                  ++s_itr_;
                  return;
               }

               if ((2 == mode))
               {
                  if (!is_end((s_itr_ + 1)) && test::comment_end(*s_itr_, *(s_itr_ + 1), mode))
                  {
                     s_itr_ += 2;
                     return;
                  }
               }

               ++s_itr_;
            }

            if (2 == mode)
            {
               token_t t;
               t.set_error(token::e_error, cmt_start, cmt_start + mode, base_itr_);
               token_list_.push_back(t);
            }
            #endif
         }

         inline bool next_is_digit(const details::char_cptr itr) const
         {
            return ((itr + 1) != s_end_) &&
                   details::is_digit(*(itr + 1));
         }

         inline void scan_token()
         {
            const char_t c = *s_itr_;

            if (details::is_whitespace(c))
            {
               skip_whitespace();
               return;
            }
            else if (is_comment_start(s_itr_))
            {
               skip_comments();
               return;
            }
            else if (details::is_operator_char(c))
            {
               scan_operator();
               return;
            }
            else if (details::is_letter(c))
            {
               scan_symbol();
               return;
            }
            else if (('.' == c) && !next_is_digit(s_itr_))
            {
               scan_operator();
               return;
            }
            else if (details::is_digit(c) || ('.' == c))
            {
               scan_number();
               return;
            }
            else if ('$' == c)
            {
               scan_special_function();
               return;
            }
            #ifndef exprtk_disable_string_capabilities
            else if ('\'' == c)
            {
               scan_string();
               return;
            }
            #endif
            else if ('~' == c)
            {
               token_t t;
               t.set_symbol(s_itr_, s_itr_ + 1, base_itr_);
               token_list_.push_back(t);
               ++s_itr_;
               return;
            }
            else
            {
               token_t t;
               t.set_error(token::e_error, s_itr_, s_itr_ + 2, base_itr_);
               token_list_.push_back(t);
               ++s_itr_;
            }
         }

         inline void scan_operator()
         {
            token_t t;

            const char_t c0 = s_itr_[0];

            if (!is_end(s_itr_ + 1))
            {
               const char_t c1 = s_itr_[1];

               if (!is_end(s_itr_ + 2))
               {
                  const char_t c2 = s_itr_[2];

                  if ((c0 == '<') && (c1 == '=') && (c2 == '>'))
                  {
                     t.set_operator(token_t::e_swap, s_itr_, s_itr_ + 3, base_itr_);
                     token_list_.push_back(t);
                     s_itr_ += 3;
                     return;
                  }
               }

               token_t::token_type ttype = token_t::e_none;

               if      ((c0 == '<') && (c1 == '=')) ttype = token_t::e_lte;
               else if ((c0 == '>') && (c1 == '=')) ttype = token_t::e_gte;
               else if ((c0 == '<') && (c1 == '>')) ttype = token_t::e_ne;
               else if ((c0 == '!') && (c1 == '=')) ttype = token_t::e_ne;
               else if ((c0 == '=') && (c1 == '=')) ttype = token_t::e_eq;
               else if ((c0 == ':') && (c1 == '=')) ttype = token_t::e_assign;
               else if ((c0 == '<') && (c1 == '<')) ttype = token_t::e_shl;
               else if ((c0 == '>') && (c1 == '>')) ttype = token_t::e_shr;
               else if ((c0 == '+') && (c1 == '=')) ttype = token_t::e_addass;
               else if ((c0 == '-') && (c1 == '=')) ttype = token_t::e_subass;
               else if ((c0 == '*') && (c1 == '=')) ttype = token_t::e_mulass;
               else if ((c0 == '/') && (c1 == '=')) ttype = token_t::e_divass;
               else if ((c0 == '%') && (c1 == '=')) ttype = token_t::e_modass;

               if (token_t::e_none != ttype)
               {
                  t.set_operator(ttype, s_itr_, s_itr_ + 2, base_itr_);
                  token_list_.push_back(t);
                  s_itr_ += 2;
                  return;
               }
            }

            if ('<' == c0)
               t.set_operator(token_t::e_lt , s_itr_, s_itr_ + 1, base_itr_);
            else if ('>' == c0)
               t.set_operator(token_t::e_gt , s_itr_, s_itr_ + 1, base_itr_);
            else if (';' == c0)
               t.set_operator(token_t::e_eof, s_itr_, s_itr_ + 1, base_itr_);
            else if ('&' == c0)
               t.set_symbol(s_itr_, s_itr_ + 1, base_itr_);
            else if ('|' == c0)
               t.set_symbol(s_itr_, s_itr_ + 1, base_itr_);
            else
               t.set_operator(token_t::token_type(c0), s_itr_, s_itr_ + 1, base_itr_);

            token_list_.push_back(t);
            ++s_itr_;
         }

         inline void scan_symbol()
         {
            details::char_cptr initial_itr = s_itr_;

            while (!is_end(s_itr_))
            {
               if (!details::is_letter_or_digit(*s_itr_) && ('_' != (*s_itr_)))
               {
                  if ('.' != (*s_itr_))
                     break;
                  /*
                     Permit symbols that contain a 'dot'
                     Allowed   : abc.xyz, a123.xyz, abc.123, abc_.xyz a123_.xyz abc._123
                     Disallowed: .abc, abc.<white-space>, abc.<eof>, abc.<operator +,-,*,/...>
                  */
                  if (
                       (s_itr_ != initial_itr)                     &&
                       !is_end(s_itr_ + 1)                         &&
                       !details::is_letter_or_digit(*(s_itr_ + 1)) &&
                       ('_' != (*(s_itr_ + 1)))
                     )
                     break;
               }

               ++s_itr_;
            }

            token_t t;
            t.set_symbol(initial_itr, s_itr_, base_itr_);
            token_list_.push_back(t);
         }

         inline void scan_number()
         {
            /*
               Attempt to match a valid numeric value in one of the following formats:
               (01) 123456
               (02) 123456.
               (03) 123.456
               (04) 123.456e3
               (05) 123.456E3
               (06) 123.456e+3
               (07) 123.456E+3
               (08) 123.456e-3
               (09) 123.456E-3
               (00) .1234
               (11) .1234e3
               (12) .1234E+3
               (13) .1234e+3
               (14) .1234E-3
               (15) .1234e-3
            */

            details::char_cptr initial_itr = s_itr_;
            bool dot_found                 = false;
            bool e_found                   = false;
            bool post_e_sign_found         = false;
            bool post_e_digit_found        = false;
            token_t t;

            while (!is_end(s_itr_))
            {
               if ('.' == (*s_itr_))
               {
                  if (dot_found)
                  {
                     t.set_error(token::e_err_number, initial_itr, s_itr_, base_itr_);
                     token_list_.push_back(t);

                     return;
                  }

                  dot_found = true;
                  ++s_itr_;

                  continue;
               }
               else if ('e' == std::tolower(*s_itr_))
               {
                  const char_t& c = *(s_itr_ + 1);

                  if (is_end(s_itr_ + 1))
                  {
                     t.set_error(token::e_err_number, initial_itr, s_itr_, base_itr_);
                     token_list_.push_back(t);

                     return;
                  }
                  else if (
                            ('+' != c) &&
                            ('-' != c) &&
                            !details::is_digit(c)
                          )
                  {
                     t.set_error(token::e_err_number, initial_itr, s_itr_, base_itr_);
                     token_list_.push_back(t);

                     return;
                  }

                  e_found = true;
                  ++s_itr_;

                  continue;
               }
               else if (e_found && details::is_sign(*s_itr_) && !post_e_digit_found)
               {
                  if (post_e_sign_found)
                  {
                     t.set_error(token::e_err_number, initial_itr, s_itr_, base_itr_);
                     token_list_.push_back(t);

                     return;
                  }

                  post_e_sign_found = true;
                  ++s_itr_;

                  continue;
               }
               else if (e_found && details::is_digit(*s_itr_))
               {
                  post_e_digit_found = true;
                  ++s_itr_;

                  continue;
               }
               else if (('.' != (*s_itr_)) && !details::is_digit(*s_itr_))
                  break;
               else
                  ++s_itr_;
            }

            t.set_numeric(initial_itr, s_itr_, base_itr_);
            token_list_.push_back(t);

            return;
         }

         inline void scan_special_function()
         {
            details::char_cptr initial_itr = s_itr_;
            token_t t;

            // $fdd(x,x,x) = at least 11 chars
            if (std::distance(s_itr_,s_end_) < 11)
            {
               t.set_error(
                  token::e_err_sfunc,
                  initial_itr, std::min(initial_itr + 11, s_end_),
                  base_itr_);
               token_list_.push_back(t);

               return;
            }

            if (
                 !(('$' == *s_itr_)                       &&
                   (details::imatch  ('f',*(s_itr_ + 1))) &&
                   (details::is_digit(*(s_itr_ + 2)))     &&
                   (details::is_digit(*(s_itr_ + 3))))
               )
            {
               t.set_error(
                  token::e_err_sfunc,
                  initial_itr, std::min(initial_itr + 4, s_end_),
                  base_itr_);
               token_list_.push_back(t);

               return;
            }

            s_itr_ += 4; // $fdd = 4chars

            t.set_symbol(initial_itr, s_itr_, base_itr_);
            token_list_.push_back(t);

            return;
         }

         #ifndef exprtk_disable_string_capabilities
         inline void scan_string()
         {
            details::char_cptr initial_itr = s_itr_ + 1;
            token_t t;

            if (std::distance(s_itr_,s_end_) < 2)
            {
               t.set_error(token::e_err_string, s_itr_, s_end_, base_itr_);
               token_list_.push_back(t);

               return;
            }

            ++s_itr_;

            bool escaped_found = false;
            bool escaped = false;

            while (!is_end(s_itr_))
            {
               if (!details::is_valid_string_char(*s_itr_))
               {
                  t.set_error(token::e_err_string, initial_itr, s_itr_, base_itr_);
                  token_list_.push_back(t);

                  return;
               }
               else if (!escaped && ('\\' == *s_itr_))
               {
                  escaped_found = true;
                  escaped = true;
                  ++s_itr_;

                  continue;
               }
               else if (!escaped)
               {
                  if ('\'' == *s_itr_)
                     break;
               }
               else if (escaped)
               {
                  if (
                       !is_end(s_itr_) && ('0' == *(s_itr_)) &&
                       ((s_itr_ + 4) <= s_end_)
                     )
                  {
                     const bool x_separator = ('X' == std::toupper(*(s_itr_ + 1)));

                     const bool both_digits = details::is_hex_digit(*(s_itr_ + 2)) &&
                                              details::is_hex_digit(*(s_itr_ + 3)) ;

                     if (!(x_separator && both_digits))
                     {
                        t.set_error(token::e_err_string, initial_itr, s_itr_, base_itr_);
                        token_list_.push_back(t);

                        return;
                     }
                     else
                        s_itr_ += 3;
                  }

                  escaped = false;
               }

               ++s_itr_;
            }

            if (is_end(s_itr_))
            {
               t.set_error(token::e_err_string, initial_itr, s_itr_, base_itr_);
               token_list_.push_back(t);

               return;
            }

            if (!escaped_found)
               t.set_string(initial_itr, s_itr_, base_itr_);
            else
            {
               std::string parsed_string(initial_itr,s_itr_);

               if (!details::cleanup_escapes(parsed_string))
               {
                  t.set_error(token::e_err_string, initial_itr, s_itr_, base_itr_);
                  token_list_.push_back(t);

                  return;
               }

               t.set_string(
                  parsed_string,
                  static_cast<std::size_t>(std::distance(base_itr_,initial_itr)));
            }

            token_list_.push_back(t);
            ++s_itr_;

            return;
         }
         #endif

      private:

         token_list_t       token_list_;
         token_list_itr_t   token_itr_;
         token_list_itr_t   store_token_itr_;
         token_t            eof_token_;
         details::char_cptr base_itr_;
         details::char_cptr s_itr_;
         details::char_cptr s_end_;

         friend class token_scanner;
         friend class token_modifier;
         friend class token_inserter;
         friend class token_joiner;
      }; // class generator

      class helper_interface
      {
      public:

         virtual void init()                     {              }
         virtual void reset()                    {              }
         virtual bool result()                   { return true; }
         virtual std::size_t process(generator&) { return 0;    }
         virtual ~helper_interface()             {              }
      };

      class token_scanner : public helper_interface
      {
      public:

         virtual ~token_scanner() exprtk_override
         {}

         explicit token_scanner(const std::size_t& stride)
         : stride_(stride)
         {
            if (stride > 4)
            {
               throw std::invalid_argument("token_scanner() - Invalid stride value");
            }
         }

         inline std::size_t process(generator& g) exprtk_override
         {
            if (g.token_list_.size() >= stride_)
            {
               for (std::size_t i = 0; i < (g.token_list_.size() - stride_ + 1); ++i)
               {
                  token t;

                  switch (stride_)
                  {
                     case 1 :
                              {
                                 const token& t0 = g.token_list_[i];

                                 if (!operator()(t0))
                                 {
                                    return 0;
                                 }
                              }
                              break;

                     case 2 :
                              {
                                 const token& t0 = g.token_list_[i    ];
                                 const token& t1 = g.token_list_[i + 1];

                                 if (!operator()(t0, t1))
                                 {
                                    return 0;
                                 }
                              }
                              break;

                     case 3 :
                              {
                                 const token& t0 = g.token_list_[i    ];
                                 const token& t1 = g.token_list_[i + 1];
                                 const token& t2 = g.token_list_[i + 2];

                                 if (!operator()(t0, t1, t2))
                                 {
                                    return 0;
                                 }
                              }
                              break;

                     case 4 :
                              {
                                 const token& t0 = g.token_list_[i    ];
                                 const token& t1 = g.token_list_[i + 1];
                                 const token& t2 = g.token_list_[i + 2];
                                 const token& t3 = g.token_list_[i + 3];

                                 if (!operator()(t0, t1, t2, t3))
                                 {
                                    return 0;
                                 }
                              }
                              break;
                  }
               }
            }

            return 0;
         }

         virtual bool operator() (const token&)
         {
            return false;
         }

         virtual bool operator() (const token&, const token&)
         {
            return false;
         }

         virtual bool operator() (const token&, const token&, const token&)
         {
            return false;
         }

         virtual bool operator() (const token&, const token&, const token&, const token&)
         {
            return false;
         }

      private:

         const std::size_t stride_;
      }; // class token_scanner

      class token_modifier : public helper_interface
      {
      public:

         inline std::size_t process(generator& g) exprtk_override
         {
            std::size_t changes = 0;

            for (std::size_t i = 0; i < g.token_list_.size(); ++i)
            {
               if (modify(g.token_list_[i])) changes++;
            }

            return changes;
         }

         virtual bool modify(token& t) = 0;
      };

      class token_inserter : public helper_interface
      {
      public:

         explicit token_inserter(const std::size_t& stride)
         : stride_(stride)
         {
            if (stride > 5)
            {
               throw std::invalid_argument("token_inserter() - Invalid stride value");
            }
         }

         inline std::size_t process(generator& g) exprtk_override
         {
            if (g.token_list_.empty())
               return 0;
            else if (g.token_list_.size() < stride_)
               return 0;

            std::size_t changes = 0;

            typedef std::pair<std::size_t, token> insert_t;
            std::vector<insert_t> insert_list;
            insert_list.reserve(10000);

            for (std::size_t i = 0; i < (g.token_list_.size() - stride_ + 1); ++i)
            {
               int insert_index = -1;
               token t;

               switch (stride_)
               {
                  case 1 : insert_index = insert(g.token_list_[i],t);
                           break;

                  case 2 : insert_index = insert(g.token_list_[i], g.token_list_[i + 1], t);
                           break;

                  case 3 : insert_index = insert(g.token_list_[i], g.token_list_[i + 1], g.token_list_[i + 2], t);
                           break;

                  case 4 : insert_index = insert(g.token_list_[i], g.token_list_[i + 1], g.token_list_[i + 2], g.token_list_[i + 3], t);
                           break;

                  case 5 : insert_index = insert(g.token_list_[i], g.token_list_[i + 1], g.token_list_[i + 2], g.token_list_[i + 3], g.token_list_[i + 4], t);
                           break;
               }

               if ((insert_index >= 0) && (insert_index <= (static_cast<int>(stride_) + 1)))
               {
                  insert_list.push_back(insert_t(i, t));
                  changes++;
               }
            }

            if (!insert_list.empty())
            {
               generator::token_list_t token_list;

               std::size_t insert_index = 0;

               for (std::size_t i = 0; i < g.token_list_.size(); ++i)
               {
                  token_list.push_back(g.token_list_[i]);

                  if (
                       (insert_index < insert_list.size()) &&
                       (insert_list[insert_index].first == i)
                     )
                  {
                     token_list.push_back(insert_list[insert_index].second);
                     insert_index++;
                  }
               }

               std::swap(g.token_list_,token_list);
            }

            return changes;
         }

         #define token_inserter_empty_body \
         {                                 \
            return -1;                     \
         }                                 \

         inline virtual int insert(const token&, token&)
         token_inserter_empty_body

         inline virtual int insert(const token&, const token&, token&)
         token_inserter_empty_body

         inline virtual int insert(const token&, const token&, const token&, token&)
         token_inserter_empty_body

         inline virtual int insert(const token&, const token&, const token&, const token&, token&)
         token_inserter_empty_body

         inline virtual int insert(const token&, const token&, const token&, const token&, const token&, token&)
         token_inserter_empty_body

         #undef token_inserter_empty_body

      private:

         const std::size_t stride_;
      };

      class token_joiner : public helper_interface
      {
      public:

         explicit token_joiner(const std::size_t& stride)
         : stride_(stride)
         {}

         inline std::size_t process(generator& g) exprtk_override
         {
            if (g.token_list_.empty())
               return 0;

            switch (stride_)
            {
               case 2  : return process_stride_2(g);
               case 3  : return process_stride_3(g);
               default : return 0;
            }
         }

         virtual bool join(const token&, const token&, token&)               { return false; }
         virtual bool join(const token&, const token&, const token&, token&) { return false; }

      private:

         inline std::size_t process_stride_2(generator& g)
         {
            if (g.token_list_.size() < 2)
               return 0;

            std::size_t changes = 0;

            generator::token_list_t token_list;
            token_list.reserve(10000);

            for (int i = 0; i < static_cast<int>(g.token_list_.size() - 1); ++i)
            {
               token t;

               for ( ; ; )
               {
                  if (!join(g[i], g[i + 1], t))
                  {
                     token_list.push_back(g[i]);
                     break;
                  }

                  token_list.push_back(t);

                  ++changes;

                  i += 2;

                  if (static_cast<std::size_t>(i) >= (g.token_list_.size() - 1))
                     break;
               }
            }

            token_list.push_back(g.token_list_.back());

            assert(token_list.size() <= g.token_list_.size());

            std::swap(token_list, g.token_list_);

            return changes;
         }

         inline std::size_t process_stride_3(generator& g)
         {
            if (g.token_list_.size() < 3)
               return 0;

            std::size_t changes = 0;

            generator::token_list_t token_list;
            token_list.reserve(10000);

            for (int i = 0; i < static_cast<int>(g.token_list_.size() - 2); ++i)
            {
               token t;

               for ( ; ; )
               {
                  if (!join(g[i], g[i + 1], g[i + 2], t))
                  {
                     token_list.push_back(g[i]);
                     break;
                  }

                  token_list.push_back(t);

                  ++changes;

                  i += 3;

                  if (static_cast<std::size_t>(i) >= (g.token_list_.size() - 2))
                     break;
               }
            }

            token_list.push_back(*(g.token_list_.begin() + g.token_list_.size() - 2));
            token_list.push_back(*(g.token_list_.begin() + g.token_list_.size() - 1));

            assert(token_list.size() <= g.token_list_.size());

            std::swap(token_list, g.token_list_);

            return changes;
         }

         const std::size_t stride_;
      };

      namespace helper
      {

         inline void dump(const lexer::generator& generator)
         {
            for (std::size_t i = 0; i < generator.size(); ++i)
            {
               const lexer::token& t = generator[i];
               printf("Token[%02d] @ %03d  %6s  -->  '%s'\n",
                      static_cast<int>(i),
                      static_cast<int>(t.position),
                      t.to_str(t.type).c_str(),
                      t.value.c_str());
            }
         }

         class commutative_inserter : public lexer::token_inserter
         {
         public:

            using lexer::token_inserter::insert;

            commutative_inserter()
            : lexer::token_inserter(2)
            {}

            inline void ignore_symbol(const std::string& symbol)
            {
               ignore_set_.insert(symbol);
            }

            inline int insert(const lexer::token& t0, const lexer::token& t1, lexer::token& new_token) exprtk_override
            {
               bool match         = false;
               new_token.type     = lexer::token::e_mul;
               new_token.value    = "*";
               new_token.position = t1.position;

               if (t0.type == lexer::token::e_symbol)
               {
                  if (ignore_set_.end() != ignore_set_.find(t0.value))
                  {
                     return -1;
                  }
                  else if (!t0.value.empty() && ('$' == t0.value[0]))
                  {
                     return -1;
                  }
               }

               if (t1.type == lexer::token::e_symbol)
               {
                  if (ignore_set_.end() != ignore_set_.find(t1.value))
                  {
                     return -1;
                  }
               }
               if      ((t0.type == lexer::token::e_number     ) && (t1.type == lexer::token::e_symbol     )) match = true;
               else if ((t0.type == lexer::token::e_number     ) && (t1.type == lexer::token::e_lbracket   )) match = true;
               else if ((t0.type == lexer::token::e_number     ) && (t1.type == lexer::token::e_lcrlbracket)) match = true;
               else if ((t0.type == lexer::token::e_number     ) && (t1.type == lexer::token::e_lsqrbracket)) match = true;
               else if ((t0.type == lexer::token::e_symbol     ) && (t1.type == lexer::token::e_number     )) match = true;
               else if ((t0.type == lexer::token::e_rbracket   ) && (t1.type == lexer::token::e_number     )) match = true;
               else if ((t0.type == lexer::token::e_rcrlbracket) && (t1.type == lexer::token::e_number     )) match = true;
               else if ((t0.type == lexer::token::e_rsqrbracket) && (t1.type == lexer::token::e_number     )) match = true;
               else if ((t0.type == lexer::token::e_rbracket   ) && (t1.type == lexer::token::e_symbol     )) match = true;
               else if ((t0.type == lexer::token::e_rcrlbracket) && (t1.type == lexer::token::e_symbol     )) match = true;
               else if ((t0.type == lexer::token::e_rsqrbracket) && (t1.type == lexer::token::e_symbol     )) match = true;
               else if ((t0.type == lexer::token::e_symbol     ) && (t1.type == lexer::token::e_symbol     )) match = true;

               return (match) ? 1 : -1;
            }

         private:

            std::set<std::string,details::ilesscompare> ignore_set_;
         };

         class operator_joiner exprtk_final : public token_joiner
         {
         public:

            explicit operator_joiner(const std::size_t& stride)
            : token_joiner(stride)
            {}

            inline bool join(const lexer::token& t0, const lexer::token& t1, lexer::token& t) exprtk_override
            {
               // ': =' --> ':='
               if ((t0.type == lexer::token::e_colon) && (t1.type == lexer::token::e_eq))
               {
                  t.type     = lexer::token::e_assign;
                  t.value    = ":=";
                  t.position = t0.position;

                  return true;
               }
               // '+ =' --> '+='
               else if ((t0.type == lexer::token::e_add) && (t1.type == lexer::token::e_eq))
               {
                  t.type     = lexer::token::e_addass;
                  t.value    = "+=";
                  t.position = t0.position;

                  return true;
               }
               // '- =' --> '-='
               else if ((t0.type == lexer::token::e_sub) && (t1.type == lexer::token::e_eq))
               {
                  t.type     = lexer::token::e_subass;
                  t.value    = "-=";
                  t.position = t0.position;

                  return true;
               }
               // '* =' --> '*='
               else if ((t0.type == lexer::token::e_mul) && (t1.type == lexer::token::e_eq))
               {
                  t.type     = lexer::token::e_mulass;
                  t.value    = "*=";
                  t.position = t0.position;

                  return true;
               }
               // '/ =' --> '/='
               else if ((t0.type == lexer::token::e_div) && (t1.type == lexer::token::e_eq))
               {
                  t.type     = lexer::token::e_divass;
                  t.value    = "/=";
                  t.position = t0.position;

                  return true;
               }
               // '% =' --> '%='
               else if ((t0.type == lexer::token::e_mod) && (t1.type == lexer::token::e_eq))
               {
                  t.type     = lexer::token::e_modass;
                  t.value    = "%=";
                  t.position = t0.position;

                  return true;
               }
               // '> =' --> '>='
               else if ((t0.type == lexer::token::e_gt) && (t1.type == lexer::token::e_eq))
               {
                  t.type     = lexer::token::e_gte;
                  t.value    = ">=";
                  t.position = t0.position;

                  return true;
               }
               // '< =' --> '<='
               else if ((t0.type == lexer::token::e_lt) && (t1.type == lexer::token::e_eq))
               {
                  t.type     = lexer::token::e_lte;
                  t.value    = "<=";
                  t.position = t0.position;

                  return true;
               }
               // '= =' --> '=='
               else if ((t0.type == lexer::token::e_eq) && (t1.type == lexer::token::e_eq))
               {
                  t.type     = lexer::token::e_eq;
                  t.value    = "==";
                  t.position = t0.position;

                  return true;
               }
               // '! =' --> '!='
               else if ((static_cast<details::char_t>(t0.type) == '!') && (t1.type == lexer::token::e_eq))
               {
                  t.type     = lexer::token::e_ne;
                  t.value    = "!=";
                  t.position = t0.position;

                  return true;
               }
               // '< >' --> '<>'
               else if ((t0.type == lexer::token::e_lt) && (t1.type == lexer::token::e_gt))
               {
                  t.type     = lexer::token::e_ne;
                  t.value    = "<>";
                  t.position = t0.position;

                  return true;
               }
               // '<= >' --> '<=>'
               else if ((t0.type == lexer::token::e_lte) && (t1.type == lexer::token::e_gt))
               {
                  t.type     = lexer::token::e_swap;
                  t.value    = "<=>";
                  t.position = t0.position;

                  return true;
               }
               // '+ -' --> '-'
               else if ((t0.type == lexer::token::e_add) && (t1.type == lexer::token::e_sub))
               {
                  t.type     = lexer::token::e_sub;
                  t.value    = "-";
                  t.position = t0.position;

                  return true;
               }
               // '- +' --> '-'
               else if ((t0.type == lexer::token::e_sub) && (t1.type == lexer::token::e_add))
               {
                  t.type     = lexer::token::e_sub;
                  t.value    = "-";
                  t.position = t0.position;

                  return true;
               }
               // '- -' --> '+'
               else if ((t0.type == lexer::token::e_sub) && (t1.type == lexer::token::e_sub))
               {
                  /*
                     Note: May need to reconsider this when wanting to implement
                     pre/postfix decrement operator
                  */
                  t.type     = lexer::token::e_add;
                  t.value    = "+";
                  t.position = t0.position;

                  return true;
               }
               else
                  return false;
            }

            inline bool join(const lexer::token& t0,
                             const lexer::token& t1,
                             const lexer::token& t2,
                             lexer::token& t) exprtk_override
            {
               // '[ * ]' --> '[*]'
               if (
                    (t0.type == lexer::token::e_lsqrbracket) &&
                    (t1.type == lexer::token::e_mul        ) &&
                    (t2.type == lexer::token::e_rsqrbracket)
                  )
               {
                  t.type     = lexer::token::e_symbol;
                  t.value    = "[*]";
                  t.position = t0.position;

                  return true;
               }
               else
                  return false;
            }
         };

         class bracket_checker exprtk_final : public lexer::token_scanner
         {
         public:

            using lexer::token_scanner::operator();

            bracket_checker()
            : token_scanner(1)
            , state_(true)
            {}

            bool result() exprtk_override
            {
               if (!stack_.empty())
               {
                  lexer::token t;
                  t.value      = stack_.top().first;
                  t.position   = stack_.top().second;
                  error_token_ = t;
                  state_       = false;

                  return false;
               }
               else
                  return state_;
            }

            lexer::token error_token() const
            {
               return error_token_;
            }

            void reset() exprtk_override
            {
               // Why? because msvc doesn't support swap properly.
               stack_ = std::stack<std::pair<char,std::size_t> >();
               state_ = true;
               error_token_.clear();
            }

            bool operator() (const lexer::token& t) exprtk_override
            {
               if (
                    !t.value.empty()                       &&
                    (lexer::token::e_string != t.type)     &&
                    (lexer::token::e_symbol != t.type)     &&
                    exprtk::details::is_bracket(t.value[0])
                  )
               {
                  details::char_t c = t.value[0];

                  if      (t.type == lexer::token::e_lbracket   ) stack_.push(std::make_pair(')',t.position));
                  else if (t.type == lexer::token::e_lcrlbracket) stack_.push(std::make_pair('}',t.position));
                  else if (t.type == lexer::token::e_lsqrbracket) stack_.push(std::make_pair(']',t.position));
                  else if (exprtk::details::is_right_bracket(c))
                  {
                     if (stack_.empty())
                     {
                        state_       = false;
                        error_token_ = t;

                        return false;
                     }
                     else if (c != stack_.top().first)
                     {
                        state_       = false;
                        error_token_ = t;

                        return false;
                     }
                     else
                        stack_.pop();
                  }
               }

               return true;
            }

         private:

            bool state_;
            std::stack<std::pair<char,std::size_t> > stack_;
            lexer::token error_token_;
         };

         template <typename T>
         class numeric_checker exprtk_final : public lexer::token_scanner
         {
         public:

            using lexer::token_scanner::operator();

            numeric_checker()
            : token_scanner (1)
            , current_index_(0)
            {}

            bool result() exprtk_override
            {
               return error_list_.empty();
            }

            void reset() exprtk_override
            {
               error_list_.clear();
               current_index_ = 0;
            }

            bool operator() (const lexer::token& t) exprtk_override
            {
               if (token::e_number == t.type)
               {
                  T v;

                  if (!exprtk::details::string_to_real(t.value,v))
                  {
                     error_list_.push_back(current_index_);
                  }
               }

               ++current_index_;

               return true;
            }

            std::size_t error_count() const
            {
               return error_list_.size();
            }

            std::size_t error_index(const std::size_t& i) const
            {
               if (i < error_list_.size())
                  return error_list_[i];
               else
                  return std::numeric_limits<std::size_t>::max();
            }

            void clear_errors()
            {
               error_list_.clear();
            }

         private:

            std::size_t current_index_;
            std::vector<std::size_t> error_list_;
         };

         class symbol_replacer exprtk_final : public lexer::token_modifier
         {
         private:

            typedef std::map<std::string,std::pair<std::string,token::token_type>,details::ilesscompare> replace_map_t;

         public:

            bool remove(const std::string& target_symbol)
            {
               const replace_map_t::iterator itr = replace_map_.find(target_symbol);

               if (replace_map_.end() == itr)
                  return false;

               replace_map_.erase(itr);

               return true;
            }

            bool add_replace(const std::string& target_symbol,
                             const std::string& replace_symbol,
                             const lexer::token::token_type token_type = lexer::token::e_symbol)
            {
               const replace_map_t::iterator itr = replace_map_.find(target_symbol);

               if (replace_map_.end() != itr)
               {
                  return false;
               }

               replace_map_[target_symbol] = std::make_pair(replace_symbol,token_type);

               return true;
            }

            void clear()
            {
               replace_map_.clear();
            }

         private:

            bool modify(lexer::token& t) exprtk_override
            {
               if (lexer::token::e_symbol == t.type)
               {
                  if (replace_map_.empty())
                     return false;

                  const replace_map_t::iterator itr = replace_map_.find(t.value);

                  if (replace_map_.end() != itr)
                  {
                     t.value = itr->second.first;
                     t.type  = itr->second.second;

                     return true;
                  }
               }

               return false;
            }

            replace_map_t replace_map_;
         };

         class sequence_validator exprtk_final : public lexer::token_scanner
         {
         private:

            typedef std::pair<lexer::token::token_type,lexer::token::token_type> token_pair_t;
            typedef std::set<token_pair_t> set_t;

         public:

            using lexer::token_scanner::operator();

            sequence_validator()
            : lexer::token_scanner(2)
            {
               add_invalid(lexer::token::e_number, lexer::token::e_number);
               add_invalid(lexer::token::e_string, lexer::token::e_string);
               add_invalid(lexer::token::e_number, lexer::token::e_string);
               add_invalid(lexer::token::e_string, lexer::token::e_number);

               add_invalid_set1(lexer::token::e_assign );
               add_invalid_set1(lexer::token::e_shr    );
               add_invalid_set1(lexer::token::e_shl    );
               add_invalid_set1(lexer::token::e_lte    );
               add_invalid_set1(lexer::token::e_ne     );
               add_invalid_set1(lexer::token::e_gte    );
               add_invalid_set1(lexer::token::e_lt     );
               add_invalid_set1(lexer::token::e_gt     );
               add_invalid_set1(lexer::token::e_eq     );
               add_invalid_set1(lexer::token::e_comma  );
               add_invalid_set1(lexer::token::e_add    );
               add_invalid_set1(lexer::token::e_sub    );
               add_invalid_set1(lexer::token::e_div    );
               add_invalid_set1(lexer::token::e_mul    );
               add_invalid_set1(lexer::token::e_mod    );
               add_invalid_set1(lexer::token::e_pow    );
               add_invalid_set1(lexer::token::e_colon  );
               add_invalid_set1(lexer::token::e_ternary);
            }

            bool result() exprtk_override
            {
               return error_list_.empty();
            }

            bool operator() (const lexer::token& t0, const lexer::token& t1) exprtk_override
            {
               const set_t::value_type p = std::make_pair(t0.type,t1.type);

               if (invalid_bracket_check(t0.type,t1.type))
               {
                  error_list_.push_back(std::make_pair(t0,t1));
               }
               else if (invalid_comb_.find(p) != invalid_comb_.end())
               {
                  error_list_.push_back(std::make_pair(t0,t1));
               }

               return true;
            }

            std::size_t error_count() const
            {
               return error_list_.size();
            }

            std::pair<lexer::token,lexer::token> error(const std::size_t index)
            {
               if (index < error_list_.size())
               {
                  return error_list_[index];
               }
               else
               {
                  static const lexer::token error_token;
                  return std::make_pair(error_token,error_token);
               }
            }

            void clear_errors()
            {
               error_list_.clear();
            }

         private:

            void add_invalid(const lexer::token::token_type base, const lexer::token::token_type t)
            {
               invalid_comb_.insert(std::make_pair(base,t));
            }

            void add_invalid_set1(const lexer::token::token_type t)
            {
               add_invalid(t, lexer::token::e_assign);
               add_invalid(t, lexer::token::e_shr   );
               add_invalid(t, lexer::token::e_shl   );
               add_invalid(t, lexer::token::e_lte   );
               add_invalid(t, lexer::token::e_ne    );
               add_invalid(t, lexer::token::e_gte   );
               add_invalid(t, lexer::token::e_lt    );
               add_invalid(t, lexer::token::e_gt    );
               add_invalid(t, lexer::token::e_eq    );
               add_invalid(t, lexer::token::e_comma );
               add_invalid(t, lexer::token::e_div   );
               add_invalid(t, lexer::token::e_mul   );
               add_invalid(t, lexer::token::e_mod   );
               add_invalid(t, lexer::token::e_pow   );
               add_invalid(t, lexer::token::e_colon );
            }

            bool invalid_bracket_check(const lexer::token::token_type base, const lexer::token::token_type t)
            {
               if (details::is_right_bracket(static_cast<details::char_t>(base)))
               {
                  switch (t)
                  {
                     case lexer::token::e_assign : return (']' != base);
                     case lexer::token::e_string : return (')' != base);
                     default                     : return false;
                  }
               }
               else if (details::is_left_bracket(static_cast<details::char_t>(base)))
               {
                  if (details::is_right_bracket(static_cast<details::char_t>(t)))
                     return false;
                  else if (details::is_left_bracket(static_cast<details::char_t>(t)))
                     return false;
                  else
                  {
                     switch (t)
                     {
                        case lexer::token::e_number  : return false;
                        case lexer::token::e_symbol  : return false;
                        case lexer::token::e_string  : return false;
                        case lexer::token::e_add     : return false;
                        case lexer::token::e_sub     : return false;
                        case lexer::token::e_colon   : return false;
                        case lexer::token::e_ternary : return false;
                        default                      : return true ;
                     }
                  }
               }
               else if (details::is_right_bracket(static_cast<details::char_t>(t)))
               {
                  switch (base)
                  {
                     case lexer::token::e_number  : return false;
                     case lexer::token::e_symbol  : return false;
                     case lexer::token::e_string  : return false;
                     case lexer::token::e_eof     : return false;
                     case lexer::token::e_colon   : return false;
                     case lexer::token::e_ternary : return false;
                     default                      : return true ;
                  }
               }
               else if (details::is_left_bracket(static_cast<details::char_t>(t)))
               {
                  switch (base)
                  {
                     case lexer::token::e_rbracket    : return true;
                     case lexer::token::e_rsqrbracket : return true;
                     case lexer::token::e_rcrlbracket : return true;
                     default                          : return false;
                  }
               }

               return false;
            }

            set_t invalid_comb_;
            std::vector<std::pair<lexer::token,lexer::token> > error_list_;
         };

         class sequence_validator_3tokens exprtk_final : public lexer::token_scanner
         {
         private:

            typedef lexer::token::token_type token_t;
            typedef std::pair<token_t,std::pair<token_t,token_t> > token_triplet_t;
            typedef std::set<token_triplet_t> set_t;

         public:

            using lexer::token_scanner::operator();

            sequence_validator_3tokens()
            : lexer::token_scanner(3)
            {
               add_invalid(lexer::token::e_number , lexer::token::e_number , lexer::token::e_number);
               add_invalid(lexer::token::e_string , lexer::token::e_string , lexer::token::e_string);
               add_invalid(lexer::token::e_comma  , lexer::token::e_comma  , lexer::token::e_comma );

               add_invalid(lexer::token::e_add    , lexer::token::e_add    , lexer::token::e_add   );
               add_invalid(lexer::token::e_sub    , lexer::token::e_sub    , lexer::token::e_sub   );
               add_invalid(lexer::token::e_div    , lexer::token::e_div    , lexer::token::e_div   );
               add_invalid(lexer::token::e_mul    , lexer::token::e_mul    , lexer::token::e_mul   );
               add_invalid(lexer::token::e_mod    , lexer::token::e_mod    , lexer::token::e_mod   );
               add_invalid(lexer::token::e_pow    , lexer::token::e_pow    , lexer::token::e_pow   );

               add_invalid(lexer::token::e_add    , lexer::token::e_sub    , lexer::token::e_add   );
               add_invalid(lexer::token::e_sub    , lexer::token::e_add    , lexer::token::e_sub   );
               add_invalid(lexer::token::e_div    , lexer::token::e_mul    , lexer::token::e_div   );
               add_invalid(lexer::token::e_mul    , lexer::token::e_div    , lexer::token::e_mul   );
               add_invalid(lexer::token::e_mod    , lexer::token::e_pow    , lexer::token::e_mod   );
               add_invalid(lexer::token::e_pow    , lexer::token::e_mod    , lexer::token::e_pow   );
            }

            bool result() exprtk_override
            {
               return error_list_.empty();
            }

            bool operator() (const lexer::token& t0, const lexer::token& t1, const lexer::token& t2) exprtk_override
            {
               const set_t::value_type p = std::make_pair(t0.type,std::make_pair(t1.type,t2.type));

               if (invalid_comb_.find(p) != invalid_comb_.end())
               {
                  error_list_.push_back(std::make_pair(t0,t1));
               }

               return true;
            }

            std::size_t error_count() const
            {
               return error_list_.size();
            }

            std::pair<lexer::token,lexer::token> error(const std::size_t index)
            {
               if (index < error_list_.size())
               {
                  return error_list_[index];
               }
               else
               {
                  static const lexer::token error_token;
                  return std::make_pair(error_token,error_token);
               }
            }

            void clear_errors()
            {
               error_list_.clear();
            }

         private:

            void add_invalid(const token_t t0, const token_t t1, const token_t t2)
            {
               invalid_comb_.insert(std::make_pair(t0,std::make_pair(t1,t2)));
            }

            set_t invalid_comb_;
            std::vector<std::pair<lexer::token,lexer::token> > error_list_;
         };

         struct helper_assembly
         {
            inline bool register_scanner(lexer::token_scanner* scanner)
            {
               if (token_scanner_list.end() != std::find(token_scanner_list.begin(),
                                                         token_scanner_list.end  (),
                                                         scanner))
               {
                  return false;
               }

               token_scanner_list.push_back(scanner);

               return true;
            }

            inline bool register_modifier(lexer::token_modifier* modifier)
            {
               if (token_modifier_list.end() != std::find(token_modifier_list.begin(),
                                                          token_modifier_list.end  (),
                                                          modifier))
               {
                  return false;
               }

               token_modifier_list.push_back(modifier);

               return true;
            }

            inline bool register_joiner(lexer::token_joiner* joiner)
            {
               if (token_joiner_list.end() != std::find(token_joiner_list.begin(),
                                                        token_joiner_list.end  (),
                                                        joiner))
               {
                  return false;
               }

               token_joiner_list.push_back(joiner);

               return true;
            }

            inline bool register_inserter(lexer::token_inserter* inserter)
            {
               if (token_inserter_list.end() != std::find(token_inserter_list.begin(),
                                                          token_inserter_list.end  (),
                                                          inserter))
               {
                  return false;
               }

               token_inserter_list.push_back(inserter);

               return true;
            }

            inline bool run_modifiers(lexer::generator& g)
            {
               error_token_modifier = reinterpret_cast<lexer::token_modifier*>(0);

               for (std::size_t i = 0; i < token_modifier_list.size(); ++i)
               {
                  lexer::token_modifier& modifier = (*token_modifier_list[i]);

                  modifier.reset();
                  modifier.process(g);

                  if (!modifier.result())
                  {
                     error_token_modifier = token_modifier_list[i];

                     return false;
                  }
               }

               return true;
            }

            inline bool run_joiners(lexer::generator& g)
            {
               error_token_joiner = reinterpret_cast<lexer::token_joiner*>(0);

               for (std::size_t i = 0; i < token_joiner_list.size(); ++i)
               {
                  lexer::token_joiner& joiner = (*token_joiner_list[i]);

                  joiner.reset();
                  joiner.process(g);

                  if (!joiner.result())
                  {
                     error_token_joiner = token_joiner_list[i];

                     return false;
                  }
               }

               return true;
            }

            inline bool run_inserters(lexer::generator& g)
            {
               error_token_inserter = reinterpret_cast<lexer::token_inserter*>(0);

               for (std::size_t i = 0; i < token_inserter_list.size(); ++i)
               {
                  lexer::token_inserter& inserter = (*token_inserter_list[i]);

                  inserter.reset();
                  inserter.process(g);

                  if (!inserter.result())
                  {
                     error_token_inserter = token_inserter_list[i];

                     return false;
                  }
               }

               return true;
            }

            inline bool run_scanners(lexer::generator& g)
            {
               error_token_scanner = reinterpret_cast<lexer::token_scanner*>(0);

               for (std::size_t i = 0; i < token_scanner_list.size(); ++i)
               {
                  lexer::token_scanner& scanner = (*token_scanner_list[i]);

                  scanner.reset();
                  scanner.process(g);

                  if (!scanner.result())
                  {
                     error_token_scanner = token_scanner_list[i];

                     return false;
                  }
               }

               return true;
            }

            std::vector<lexer::token_scanner*>  token_scanner_list;
            std::vector<lexer::token_modifier*> token_modifier_list;
            std::vector<lexer::token_joiner*>   token_joiner_list;
            std::vector<lexer::token_inserter*> token_inserter_list;

            lexer::token_scanner*  error_token_scanner;
            lexer::token_modifier* error_token_modifier;
            lexer::token_joiner*   error_token_joiner;
            lexer::token_inserter* error_token_inserter;
         };
      }

      class parser_helper
      {
      public:

         typedef token     token_t;
         typedef generator generator_t;

         inline bool init(const std::string& str)
         {
            if (!lexer_.process(str))
            {
               return false;
            }

            lexer_.begin();

            next_token();

            return true;
         }

         inline generator_t& lexer()
         {
            return lexer_;
         }

         inline const generator_t& lexer() const
         {
            return lexer_;
         }

         inline void store_token()
         {
            lexer_.store();
            store_current_token_ = current_token_;
         }

         inline void restore_token()
         {
            lexer_.restore();
            current_token_ = store_current_token_;
         }

         inline void next_token()
         {
            current_token_ = lexer_.next_token();
         }

         inline const token_t& current_token() const
         {
            return current_token_;
         }

         inline const token_t& peek_next_token()
         {
            return lexer_.peek_next_token();
         }

         enum token_advance_mode
         {
            e_hold    = 0,
            e_advance = 1
         };

         inline void advance_token(const token_advance_mode mode)
         {
            if (e_advance == mode)
            {
               next_token();
            }
         }

         inline bool token_is(const token_t::token_type& ttype, const token_advance_mode mode = e_advance)
         {
            if (current_token().type != ttype)
            {
               return false;
            }

            advance_token(mode);

            return true;
         }

         inline bool token_is(const token_t::token_type& ttype,
                              const std::string& value,
                              const token_advance_mode mode = e_advance)
         {
            if (
                 (current_token().type != ttype) ||
                 !exprtk::details::imatch(value,current_token().value)
               )
            {
               return false;
            }

            advance_token(mode);

            return true;
         }

         inline bool token_is(const std::string& value,
                              const token_advance_mode mode = e_advance)
         {
            if (!exprtk::details::imatch(value,current_token().value))
            {
               return false;
            }

            advance_token(mode);

            return true;
         }

         inline bool token_is_arithmetic_opr(const token_advance_mode mode = e_advance)
         {
            switch (current_token().type)
            {
               case token_t::e_add :
               case token_t::e_sub :
               case token_t::e_div :
               case token_t::e_mul :
               case token_t::e_mod :
               case token_t::e_pow : break;
               default             : return false;
            }

            advance_token(mode);

            return true;
         }

         inline bool token_is_ineq_opr(const token_advance_mode mode = e_advance)
         {
            switch (current_token().type)
            {
               case token_t::e_eq  :
               case token_t::e_lte :
               case token_t::e_ne  :
               case token_t::e_gte :
               case token_t::e_lt  :
               case token_t::e_gt  : break;
               default             : return false;
            }

            advance_token(mode);

            return true;
         }

         inline bool token_is_left_bracket(const token_advance_mode mode = e_advance)
         {
            switch (current_token().type)
            {
               case token_t::e_lbracket    :
               case token_t::e_lcrlbracket :
               case token_t::e_lsqrbracket : break;
               default                     : return false;
            }

            advance_token(mode);

            return true;
         }

         inline bool token_is_right_bracket(const token_advance_mode mode = e_advance)
         {
            switch (current_token().type)
            {
               case token_t::e_rbracket    :
               case token_t::e_rcrlbracket :
               case token_t::e_rsqrbracket : break;
               default                     : return false;
            }

            advance_token(mode);

            return true;
         }

         inline bool token_is_bracket(const token_advance_mode mode = e_advance)
         {
            switch (current_token().type)
            {
               case token_t::e_rbracket    :
               case token_t::e_rcrlbracket :
               case token_t::e_rsqrbracket :
               case token_t::e_lbracket    :
               case token_t::e_lcrlbracket :
               case token_t::e_lsqrbracket : break;
               default                     : return false;
            }

            advance_token(mode);

            return true;
         }

         inline bool token_is_loop(const token_advance_mode mode = e_advance)
         {
            return token_is("for"   , mode) ||
                   token_is("while" , mode) ||
                   token_is("repeat", mode) ;
         }

         inline bool peek_token_is(const token_t::token_type& ttype)
         {
            return (lexer_.peek_next_token().type == ttype);
         }

         inline bool peek_token_is(const std::string& s)
         {
            return (exprtk::details::imatch(lexer_.peek_next_token().value,s));
         }

      private:

         generator_t lexer_;
         token_t     current_token_;
         token_t     store_current_token_;
      };
   }

   template <typename T>
   class vector_view
   {
   public:

      typedef T* data_ptr_t;

      vector_view(data_ptr_t data, const std::size_t& size)
      : base_size_(size)
      , size_(size)
      , data_(data)
      , data_ref_(0)
      {
         assert(size_ > 0);
      }

      vector_view(const vector_view<T>& vv)
      : base_size_(vv.base_size_)
      , size_(vv.size_)
      , data_(vv.data_)
      , data_ref_(0)
      {
         assert(size_ > 0);
      }

      inline void rebase(data_ptr_t data)
      {
         data_ = data;

         if (!data_ref_.empty())
         {
            for (std::size_t i = 0; i < data_ref_.size(); ++i)
            {
               (*data_ref_[i]) = data;
            }
         }
      }

      inline data_ptr_t data() const
      {
         return data_;
      }

      inline std::size_t base_size() const
      {
         return base_size_;
      }

      inline std::size_t size() const
      {
         return size_;
      }

      inline const T& operator[](const std::size_t index) const
      {
         assert(index < size_);
         return data_[index];
      }

      inline T& operator[](const std::size_t index)
      {
         assert(index < size_);
         return data_[index];
      }

      void set_ref(data_ptr_t* data_ref)
      {
         data_ref_.push_back(data_ref);
         exprtk_debug(("vector_view::set_ref() - data_ref: %p data_ref_.size(): %d\n",
                       reinterpret_cast<void*>(data_ref),
                       static_cast<int>(data_ref_.size())));
      }

      void remove_ref(data_ptr_t* data_ref)
      {
         data_ref_.erase(
            std::remove(data_ref_.begin(), data_ref_.end(), data_ref),
            data_ref_.end());
         exprtk_debug(("vector_view::remove_ref() - data_ref: %p data_ref_.size(): %d\n",
                       reinterpret_cast<void*>(data_ref),
                       static_cast<int>(data_ref_.size())));
      }

      bool set_size(const std::size_t new_size)
      {
         if ((new_size > 0) && (new_size <= base_size_))
         {
            size_ = new_size;
            exprtk_debug(("vector_view::set_size() - data_: %p size: %lu\n",
                          reinterpret_cast<void*>(data_),
                          size_));
            return true;
         }

         exprtk_debug(("vector_view::set_size() - error invalid new_size: %lu  base_size: %lu\n",
                       new_size,
                       base_size_));
         return false;
      }

   private:

      const std::size_t base_size_;
      std::size_t size_;
      data_ptr_t  data_;
      std::vector<data_ptr_t*> data_ref_;
   };

   template <typename T>
   inline vector_view<T> make_vector_view(T* data,
                                          const std::size_t size, const std::size_t offset = 0)
   {
      return vector_view<T>(data + offset, size);
   }

   template <typename T>
   inline vector_view<T> make_vector_view(std::vector<T>& v,
                                          const std::size_t size, const std::size_t offset = 0)
   {
      return vector_view<T>(v.data() + offset, size);
   }

   template <typename T> class results_context;

   template <typename T>
   struct type_store
   {
      enum store_type
      {
         e_unknown,
         e_scalar ,
         e_vector ,
         e_string
      };

      type_store()
      : data(0)
      , size(0)
      , type(e_unknown)
      {}

      union
      {
         void* data;
         T*    vec_data;
      };

      std::size_t size;
      store_type  type;

      class parameter_list
      {
      public:

         explicit parameter_list(std::vector<type_store>& pl)
         : parameter_list_(pl)
         {}

         inline bool empty() const
         {
            return parameter_list_.empty();
         }

         inline std::size_t size() const
         {
            return parameter_list_.size();
         }

         inline type_store& operator[](const std::size_t& index)
         {
            return parameter_list_[index];
         }

         inline const type_store& operator[](const std::size_t& index) const
         {
            return parameter_list_[index];
         }

         inline type_store& front()
         {
            return parameter_list_[0];
         }

         inline const type_store& front() const
         {
            return parameter_list_[0];
         }

         inline type_store& back()
         {
            return parameter_list_.back();
         }

         inline const type_store& back() const
         {
            return parameter_list_.back();
         }

      private:

         std::vector<type_store>& parameter_list_;

         friend class results_context<T>;
      };

      template <typename ViewType>
      struct type_view
      {
         typedef type_store<T> type_store_t;
         typedef ViewType      value_t;

         explicit type_view(type_store_t& ts)
         : ts_(ts)
         , data_(reinterpret_cast<value_t*>(ts_.data))
         {}

         explicit type_view(const type_store_t& ts)
         : ts_(const_cast<type_store_t&>(ts))
         , data_(reinterpret_cast<value_t*>(ts_.data))
         {}

         inline std::size_t size() const
         {
            return ts_.size;
         }

         inline value_t& operator[](const std::size_t& i)
         {
            return data_[i];
         }

         inline const value_t& operator[](const std::size_t& i) const
         {
            return data_[i];
         }

         inline const value_t* begin() const { return data_; }
         inline       value_t* begin()       { return data_; }

         inline const value_t* end() const
         {
            return static_cast<value_t*>(data_ + ts_.size);
         }

         inline value_t* end()
         {
            return static_cast<value_t*>(data_ + ts_.size);
         }

         type_store_t& ts_;
         value_t* data_;
      };

      typedef type_view<T>    vector_view;
      typedef type_view<char> string_view;

      struct scalar_view
      {
         typedef type_store<T> type_store_t;
         typedef T value_t;

         explicit scalar_view(type_store_t& ts)
         : v_(*reinterpret_cast<value_t*>(ts.data))
         {}

         explicit scalar_view(const type_store_t& ts)
         : v_(*reinterpret_cast<value_t*>(const_cast<type_store_t&>(ts).data))
         {}

         inline value_t& operator() ()
         {
            return v_;
         }

         inline const value_t& operator() () const
         {
            return v_;
         }

         inline operator value_t() const
         {
            return v_;
         }

         inline operator value_t()
         {
            return v_;
         }

         template <typename IntType>
         inline bool to_int(IntType& i) const
         {
            if (!exprtk::details::numeric::is_integer(v_))
               return false;

            i = static_cast<IntType>(v_);

            return true;
         }

         template <typename UIntType>
         inline bool to_uint(UIntType& u) const
         {
            if (v_ < T(0))
               return false;
            else if (!exprtk::details::numeric::is_integer(v_))
               return false;

            u = static_cast<UIntType>(v_);

            return true;
         }

         T& v_;
      };
   };

   template <typename StringView>
   inline std::string to_str(const StringView& view)
   {
      return std::string(view.begin(),view.size());
   }

   #ifndef exprtk_disable_return_statement
   namespace details
   {
      template <typename T> class return_node;
      template <typename T> class return_envelope_node;
   }
   #endif

   template <typename T>
   class results_context
   {
   public:

      typedef type_store<T> type_store_t;
      typedef typename type_store_t::scalar_view scalar_t;
      typedef typename type_store_t::vector_view vector_t;
      typedef typename type_store_t::string_view string_t;

      results_context()
      : results_available_(false)
      {}

      inline std::size_t count() const
      {
         if (results_available_)
            return parameter_list_.size();
         else
            return 0;
      }

      inline type_store_t& operator[](const std::size_t& index)
      {
         return parameter_list_[index];
      }

      inline const type_store_t& operator[](const std::size_t& index) const
      {
         return parameter_list_[index];
      }

      inline bool get_scalar(const std::size_t& index, T& out) const
      {
         if (
              (index < parameter_list_.size()) &&
              (parameter_list_[index].type == type_store_t::e_scalar)
            )
         {
            const scalar_t scalar(parameter_list_[index]);
            out = scalar();
            return true;
         }

         return false;
      }

      template <typename OutputIterator>
      inline bool get_vector(const std::size_t& index, OutputIterator out_itr) const
      {
         if (
              (index < parameter_list_.size()) &&
              (parameter_list_[index].type == type_store_t::e_vector)
            )
         {
            const vector_t vector(parameter_list_[index]);
            for (std::size_t i = 0; i < vector.size(); ++i)
            {
               *(out_itr++) = vector[i];
            }

            return true;
         }

         return false;
      }

      inline bool get_vector(const std::size_t& index, std::vector<T>& out) const
      {
         return get_vector(index,std::back_inserter(out));
      }

      inline bool get_string(const std::size_t& index, std::string& out) const
      {
         if (
              (index < parameter_list_.size()) &&
              (parameter_list_[index].type == type_store_t::e_string)
            )
         {
            const string_t str(parameter_list_[index]);
            out.assign(str.begin(),str.size());
            return true;
         }

         return false;
      }

   private:

      inline void clear()
      {
         results_available_ = false;
      }

      typedef std::vector<type_store_t> ts_list_t;
      typedef typename type_store_t::parameter_list parameter_list_t;

      inline void assign(const parameter_list_t& pl)
      {
         parameter_list_    = pl.parameter_list_;
         results_available_ = true;
      }

      bool results_available_;
      ts_list_t parameter_list_;

      #ifndef exprtk_disable_return_statement
      friend class details::return_node<T>;
      friend class details::return_envelope_node<T>;
      #endif
   };

   namespace details
   {
      enum operator_type
      {
         e_default , e_null    , e_add     , e_sub     ,
         e_mul     , e_div     , e_mod     , e_pow     ,
         e_atan2   , e_min     , e_max     , e_avg     ,
         e_sum     , e_prod    , e_lt      , e_lte     ,
         e_eq      , e_equal   , e_ne      , e_nequal  ,
         e_gte     , e_gt      , e_and     , e_nand    ,
         e_or      , e_nor     , e_xor     , e_xnor    ,
         e_mand    , e_mor     , e_scand   , e_scor    ,
         e_shr     , e_shl     , e_abs     , e_acos    ,
         e_acosh   , e_asin    , e_asinh   , e_atan    ,
         e_atanh   , e_ceil    , e_cos     , e_cosh    ,
         e_exp     , e_expm1   , e_floor   , e_log     ,
         e_log10   , e_log2    , e_log1p   , e_logn    ,
         e_neg     , e_pos     , e_round   , e_roundn  ,
         e_root    , e_sqrt    , e_sin     , e_sinc    ,
         e_sinh    , e_sec     , e_csc     , e_tan     ,
         e_tanh    , e_cot     , e_clamp   , e_iclamp  ,
         e_inrange , e_sgn     , e_r2d     , e_d2r     ,
         e_d2g     , e_g2d     , e_hypot   , e_notl    ,
         e_erf     , e_erfc    , e_ncdf    , e_frac    ,
         e_trunc   , e_assign  , e_addass  , e_subass  ,
         e_mulass  , e_divass  , e_modass  , e_in      ,
         e_like    , e_ilike   , e_multi   , e_smulti  ,
         e_swap    ,

         // Do not add new functions/operators after this point.
         e_sf00 = 1000, e_sf01 = 1001, e_sf02 = 1002, e_sf03 = 1003,
         e_sf04 = 1004, e_sf05 = 1005, e_sf06 = 1006, e_sf07 = 1007,
         e_sf08 = 1008, e_sf09 = 1009, e_sf10 = 1010, e_sf11 = 1011,
         e_sf12 = 1012, e_sf13 = 1013, e_sf14 = 1014, e_sf15 = 1015,
         e_sf16 = 1016, e_sf17 = 1017, e_sf18 = 1018, e_sf19 = 1019,
         e_sf20 = 1020, e_sf21 = 1021, e_sf22 = 1022, e_sf23 = 1023,
         e_sf24 = 1024, e_sf25 = 1025, e_sf26 = 1026, e_sf27 = 1027,
         e_sf28 = 1028, e_sf29 = 1029, e_sf30 = 1030, e_sf31 = 1031,
         e_sf32 = 1032, e_sf33 = 1033, e_sf34 = 1034, e_sf35 = 1035,
         e_sf36 = 1036, e_sf37 = 1037, e_sf38 = 1038, e_sf39 = 1039,
         e_sf40 = 1040, e_sf41 = 1041, e_sf42 = 1042, e_sf43 = 1043,
         e_sf44 = 1044, e_sf45 = 1045, e_sf46 = 1046, e_sf47 = 1047,
         e_sf48 = 1048, e_sf49 = 1049, e_sf50 = 1050, e_sf51 = 1051,
         e_sf52 = 1052, e_sf53 = 1053, e_sf54 = 1054, e_sf55 = 1055,
         e_sf56 = 1056, e_sf57 = 1057, e_sf58 = 1058, e_sf59 = 1059,
         e_sf60 = 1060, e_sf61 = 1061, e_sf62 = 1062, e_sf63 = 1063,
         e_sf64 = 1064, e_sf65 = 1065, e_sf66 = 1066, e_sf67 = 1067,
         e_sf68 = 1068, e_sf69 = 1069, e_sf70 = 1070, e_sf71 = 1071,
         e_sf72 = 1072, e_sf73 = 1073, e_sf74 = 1074, e_sf75 = 1075,
         e_sf76 = 1076, e_sf77 = 1077, e_sf78 = 1078, e_sf79 = 1079,
         e_sf80 = 1080, e_sf81 = 1081, e_sf82 = 1082, e_sf83 = 1083,
         e_sf84 = 1084, e_sf85 = 1085, e_sf86 = 1086, e_sf87 = 1087,
         e_sf88 = 1088, e_sf89 = 1089, e_sf90 = 1090, e_sf91 = 1091,
         e_sf92 = 1092, e_sf93 = 1093, e_sf94 = 1094, e_sf95 = 1095,
         e_sf96 = 1096, e_sf97 = 1097, e_sf98 = 1098, e_sf99 = 1099,
         e_sffinal  = 1100,
         e_sf4ext00 = 2000, e_sf4ext01 = 2001, e_sf4ext02 = 2002, e_sf4ext03 = 2003,
         e_sf4ext04 = 2004, e_sf4ext05 = 2005, e_sf4ext06 = 2006, e_sf4ext07 = 2007,
         e_sf4ext08 = 2008, e_sf4ext09 = 2009, e_sf4ext10 = 2010, e_sf4ext11 = 2011,
         e_sf4ext12 = 2012, e_sf4ext13 = 2013, e_sf4ext14 = 2014, e_sf4ext15 = 2015,
         e_sf4ext16 = 2016, e_sf4ext17 = 2017, e_sf4ext18 = 2018, e_sf4ext19 = 2019,
         e_sf4ext20 = 2020, e_sf4ext21 = 2021, e_sf4ext22 = 2022, e_sf4ext23 = 2023,
         e_sf4ext24 = 2024, e_sf4ext25 = 2025, e_sf4ext26 = 2026, e_sf4ext27 = 2027,
         e_sf4ext28 = 2028, e_sf4ext29 = 2029, e_sf4ext30 = 2030, e_sf4ext31 = 2031,
         e_sf4ext32 = 2032, e_sf4ext33 = 2033, e_sf4ext34 = 2034, e_sf4ext35 = 2035,
         e_sf4ext36 = 2036, e_sf4ext37 = 2037, e_sf4ext38 = 2038, e_sf4ext39 = 2039,
         e_sf4ext40 = 2040, e_sf4ext41 = 2041, e_sf4ext42 = 2042, e_sf4ext43 = 2043,
         e_sf4ext44 = 2044, e_sf4ext45 = 2045, e_sf4ext46 = 2046, e_sf4ext47 = 2047,
         e_sf4ext48 = 2048, e_sf4ext49 = 2049, e_sf4ext50 = 2050, e_sf4ext51 = 2051,
         e_sf4ext52 = 2052, e_sf4ext53 = 2053, e_sf4ext54 = 2054, e_sf4ext55 = 2055,
         e_sf4ext56 = 2056, e_sf4ext57 = 2057, e_sf4ext58 = 2058, e_sf4ext59 = 2059,
         e_sf4ext60 = 2060, e_sf4ext61 = 2061
      };

      inline std::string to_str(const operator_type opr)
      {
         switch (opr)
         {
            case e_add    : return  "+"  ;
            case e_sub    : return  "-"  ;
            case e_mul    : return  "*"  ;
            case e_div    : return  "/"  ;
            case e_mod    : return  "%"  ;
            case e_pow    : return  "^"  ;
            case e_assign : return ":="  ;
            case e_addass : return "+="  ;
            case e_subass : return "-="  ;
            case e_mulass : return "*="  ;
            case e_divass : return "/="  ;
            case e_modass : return "%="  ;
            case e_lt     : return  "<"  ;
            case e_lte    : return "<="  ;
            case e_eq     : return "=="  ;
            case e_equal  : return  "="  ;
            case e_ne     : return "!="  ;
            case e_nequal : return "<>"  ;
            case e_gte    : return ">="  ;
            case e_gt     : return  ">"  ;
            case e_and    : return "and" ;
            case e_or     : return "or"  ;
            case e_xor    : return "xor" ;
            case e_nand   : return "nand";
            case e_nor    : return "nor" ;
            case e_xnor   : return "xnor";
            default       : return "N/A" ;
         }
      }

      struct base_operation_t
      {
         base_operation_t(const operator_type t, const unsigned int& np)
         : type(t)
         , num_params(np)
         {}

         operator_type type;
         unsigned int num_params;
      };

      namespace loop_unroll
      {
         const unsigned int global_loop_batch_size =
         #ifndef exprtk_disable_superscalar_unroll
         16;
         #else
          4;
         #endif

         struct details
         {
            explicit details(const std::size_t& vsize,
                             const unsigned int loop_batch_size = global_loop_batch_size)
            : batch_size(loop_batch_size   )
            , remainder (vsize % batch_size)
            , upper_bound(static_cast<int>(vsize - (remainder ? loop_batch_size : 0)))
            {}

            unsigned int batch_size;
            int remainder;
            int upper_bound;
         };
      }

      #ifdef exprtk_enable_debugging
      inline void dump_ptr(const std::string& s, const void* ptr, const std::size_t size = 0)
      {
         if (size)
            exprtk_debug(("%s - addr: %p size: %d\n",
                          s.c_str(),
                          ptr,
                          static_cast<unsigned int>(size)));
         else
            exprtk_debug(("%s - addr: %p\n", s.c_str(), ptr));
      }

      template <typename T>
      inline void dump_vector(const std::string& vec_name, const T* data, const std::size_t size)
      {
         printf("----- %s (%p) -----\n",
                vec_name.c_str(),
                static_cast<const void*>(data));
         printf("[ ");
         for (std::size_t i = 0; i <  size; ++i)
         {
            printf("%8.3f\t", data[i]);
         }
         printf(" ]\n");
         printf("---------------------\n");
      }
      #else
      inline void dump_ptr(const std::string&, const void*) {}
      inline void dump_ptr(const std::string&, const void*, const std::size_t) {}
      template <typename T>
      inline void dump_vector(const std::string&, const T*, const std::size_t) {}
      #endif

      template <typename T>
      class vec_data_store
      {
      public:

         typedef vec_data_store<T> type;
         typedef T* data_t;

      private:

         struct control_block
         {
            control_block()
            : ref_count(1)
            , size     (0)
            , data     (0)
            , destruct (true)
            {}

            explicit control_block(const std::size_t& dsize)
            : ref_count(1    )
            , size     (dsize)
            , data     (0    )
            , destruct (true )
            { create_data(); }

            control_block(const std::size_t& dsize, data_t dptr, bool dstrct = false)
            : ref_count(1     )
            , size     (dsize )
            , data     (dptr  )
            , destruct (dstrct)
            {}

           ~control_block()
            {
               if (data && destruct && (0 == ref_count))
               {
                  dump_ptr("~vec_data_store::control_block() data",data);
                  delete[] data;
                  data = reinterpret_cast<data_t>(0);
               }
            }

            static inline control_block* create(const std::size_t& dsize, data_t data_ptr = data_t(0), bool dstrct = false)
            {
               if (dsize)
               {
                  if (0 == data_ptr)
                     return (new control_block(dsize));
                  else
                     return (new control_block(dsize, data_ptr, dstrct));
               }
               else
                  return (new control_block);
            }

            static inline void destroy(control_block*& cntrl_blck)
            {
               if (cntrl_blck)
               {
                  if (
                       (0 !=   cntrl_blck->ref_count) &&
                       (0 == --cntrl_blck->ref_count)
                     )
                  {
                     delete cntrl_blck;
                  }

                  cntrl_blck = 0;
               }
            }

            std::size_t ref_count;
            std::size_t size;
            data_t      data;
            bool        destruct;

         private:

            control_block(const control_block&) exprtk_delete;
            control_block& operator=(const control_block&) exprtk_delete;

            inline void create_data()
            {
               destruct = true;
               data     = new T[size];
               std::fill_n(data, size, T(0));
               dump_ptr("control_block::create_data() - data", data, size);
            }
         };

      public:

         vec_data_store()
         : control_block_(control_block::create(0))
         {}

         explicit vec_data_store(const std::size_t& size)
         : control_block_(control_block::create(size,reinterpret_cast<data_t>(0),true))
         {}

         vec_data_store(const std::size_t& size, data_t data, bool dstrct = false)
         : control_block_(control_block::create(size, data, dstrct))
         {}

         vec_data_store(const type& vds)
         {
            control_block_ = vds.control_block_;
            control_block_->ref_count++;
         }

        ~vec_data_store()
         {
            control_block::destroy(control_block_);
         }

         type& operator=(const type& vds)
         {
            if (this != &vds)
            {
               const std::size_t final_size = min_size(control_block_, vds.control_block_);

               vds.control_block_->size = final_size;
                   control_block_->size = final_size;

               if (control_block_->destruct || (0 == control_block_->data))
               {
                  control_block::destroy(control_block_);

                  control_block_ = vds.control_block_;
                  control_block_->ref_count++;
               }
            }

            return (*this);
         }

         inline data_t data()
         {
            return control_block_->data;
         }

         inline data_t data() const
         {
            return control_block_->data;
         }

         inline std::size_t size() const
         {
            return control_block_->size;
         }

         inline data_t& ref()
         {
            return control_block_->data;
         }

         inline void dump() const
         {
            #ifdef exprtk_enable_debugging
            exprtk_debug(("size: %d\taddress:%p\tdestruct:%c\n",
                          size(),
                          data(),
                          (control_block_->destruct ? 'T' : 'F')));

            for (std::size_t i = 0; i < size(); ++i)
            {
               if (5 == i)
                  exprtk_debug(("\n"));

               exprtk_debug(("%15.10f ", data()[i]));
            }
            exprtk_debug(("\n"));
            #endif
         }

         static inline void match_sizes(type& vds0, type& vds1)
         {
            const std::size_t size = min_size(vds0.control_block_,vds1.control_block_);
            vds0.control_block_->size = size;
            vds1.control_block_->size = size;
         }

      private:

         static inline std::size_t min_size(const control_block* cb0, const control_block* cb1)
         {
            const std::size_t size0 = cb0->size;
            const std::size_t size1 = cb1->size;

            if (size0 && size1)
               return std::min(size0,size1);
            else
               return (size0) ? size0 : size1;
         }

         control_block* control_block_;
      };

      namespace numeric
      {
         namespace details
         {
            template <typename T>
            inline T process_impl(const operator_type operation, const T arg)
            {
               switch (operation)
               {
                  case e_abs   : return numeric::abs  (arg);
                  case e_acos  : return numeric::acos (arg);
                  case e_acosh : return numeric::acosh(arg);
                  case e_asin  : return numeric::asin (arg);
                  case e_asinh : return numeric::asinh(arg);
                  case e_atan  : return numeric::atan (arg);
                  case e_atanh : return numeric::atanh(arg);
                  case e_ceil  : return numeric::ceil (arg);
                  case e_cos   : return numeric::cos  (arg);
                  case e_cosh  : return numeric::cosh (arg);
                  case e_exp   : return numeric::exp  (arg);
                  case e_expm1 : return numeric::expm1(arg);
                  case e_floor : return numeric::floor(arg);
                  case e_log   : return numeric::log  (arg);
                  case e_log10 : return numeric::log10(arg);
                  case e_log2  : return numeric::log2 (arg);
                  case e_log1p : return numeric::log1p(arg);
                  case e_neg   : return numeric::neg  (arg);
                  case e_pos   : return numeric::pos  (arg);
                  case e_round : return numeric::round(arg);
                  case e_sin   : return numeric::sin  (arg);
                  case e_sinc  : return numeric::sinc (arg);
                  case e_sinh  : return numeric::sinh (arg);
                  case e_sqrt  : return numeric::sqrt (arg);
                  case e_tan   : return numeric::tan  (arg);
                  case e_tanh  : return numeric::tanh (arg);
                  case e_cot   : return numeric::cot  (arg);
                  case e_sec   : return numeric::sec  (arg);
                  case e_csc   : return numeric::csc  (arg);
                  case e_r2d   : return numeric::r2d  (arg);
                  case e_d2r   : return numeric::d2r  (arg);
                  case e_d2g   : return numeric::d2g  (arg);
                  case e_g2d   : return numeric::g2d  (arg);
                  case e_notl  : return numeric::notl (arg);
                  case e_sgn   : return numeric::sgn  (arg);
                  case e_erf   : return numeric::erf  (arg);
                  case e_erfc  : return numeric::erfc (arg);
                  case e_ncdf  : return numeric::ncdf (arg);
                  case e_frac  : return numeric::frac (arg);
                  case e_trunc : return numeric::trunc(arg);

                  default      : exprtk_debug(("numeric::details::process_impl<T> - Invalid unary operation.\n"));
                                 return std::numeric_limits<T>::quiet_NaN();
               }
            }

            template <typename T>
            inline T process_impl(const operator_type operation, const T arg0, const T arg1)
            {
               switch (operation)
               {
                  case e_add    : return (arg0 + arg1);
                  case e_sub    : return (arg0 - arg1);
                  case e_mul    : return (arg0 * arg1);
                  case e_div    : return (arg0 / arg1);
                  case e_mod    : return modulus<T>(arg0,arg1);
                  case e_pow    : return pow<T>(arg0,arg1);
                  case e_atan2  : return atan2<T>(arg0,arg1);
                  case e_min    : return std::min<T>(arg0,arg1);
                  case e_max    : return std::max<T>(arg0,arg1);
                  case e_logn   : return logn<T>(arg0,arg1);
                  case e_lt     : return (arg0 <  arg1) ? T(1) : T(0);
                  case e_lte    : return (arg0 <= arg1) ? T(1) : T(0);
                  case e_eq     : return std::equal_to<T>()(arg0,arg1) ? T(1) : T(0);
                  case e_ne     : return std::not_equal_to<T>()(arg0,arg1) ? T(1) : T(0);
                  case e_gte    : return (arg0 >= arg1) ? T(1) : T(0);
                  case e_gt     : return (arg0 >  arg1) ? T(1) : T(0);
                  case e_and    : return and_opr <T>(arg0,arg1);
                  case e_nand   : return nand_opr<T>(arg0,arg1);
                  case e_or     : return or_opr  <T>(arg0,arg1);
                  case e_nor    : return nor_opr <T>(arg0,arg1);
                  case e_xor    : return xor_opr <T>(arg0,arg1);
                  case e_xnor   : return xnor_opr<T>(arg0,arg1);
                  case e_root   : return root    <T>(arg0,arg1);
                  case e_roundn : return roundn  <T>(arg0,arg1);
                  case e_equal  : return equal   <T>(arg0,arg1);
                  case e_nequal : return nequal  <T>(arg0,arg1);
                  case e_hypot  : return hypot   <T>(arg0,arg1);
                  case e_shr    : return shr     <T>(arg0,arg1);
                  case e_shl    : return shl     <T>(arg0,arg1);

                  default       : exprtk_debug(("numeric::details::process_impl<T> - Invalid binary operation.\n"));
                                  return std::numeric_limits<T>::quiet_NaN();
               }
            }

            template <typename T>
            inline T process_impl(const operator_type operation, const T arg0, const T arg1, int_type_tag)
            {
               switch (operation)
               {
                  case e_add    : return (arg0 + arg1);
                  case e_sub    : return (arg0 - arg1);
                  case e_mul    : return (arg0 * arg1);
                  case e_div    : return (arg0 / arg1);
                  case e_mod    : return arg0 % arg1;
                  case e_pow    : return pow<T>(arg0,arg1);
                  case e_min    : return std::min<T>(arg0,arg1);
                  case e_max    : return std::max<T>(arg0,arg1);
                  case e_logn   : return logn<T>(arg0,arg1);
                  case e_lt     : return (arg0 <  arg1) ? T(1) : T(0);
                  case e_lte    : return (arg0 <= arg1) ? T(1) : T(0);
                  case e_eq     : return (arg0 == arg1) ? T(1) : T(0);
                  case e_ne     : return (arg0 != arg1) ? T(1) : T(0);
                  case e_gte    : return (arg0 >= arg1) ? T(1) : T(0);
                  case e_gt     : return (arg0 >  arg1) ? T(1) : T(0);
                  case e_and    : return ((arg0 != T(0)) && (arg1 != T(0))) ? T(1) : T(0);
                  case e_nand   : return ((arg0 != T(0)) && (arg1 != T(0))) ? T(0) : T(1);
                  case e_or     : return ((arg0 != T(0)) || (arg1 != T(0))) ? T(1) : T(0);
                  case e_nor    : return ((arg0 != T(0)) || (arg1 != T(0))) ? T(0) : T(1);
                  case e_xor    : return arg0 ^ arg1;
                  case e_xnor   : return !(arg0 ^ arg1);
                  case e_root   : return root<T>(arg0,arg1);
                  case e_equal  : return arg0 == arg1;
                  case e_nequal : return arg0 != arg1;
                  case e_hypot  : return hypot<T>(arg0,arg1);
                  case e_shr    : return arg0 >> arg1;
                  case e_shl    : return arg0 << arg1;

                  default       : exprtk_debug(("numeric::details::process_impl<IntType> - Invalid binary operation.\n"));
                                  return std::numeric_limits<T>::quiet_NaN();
               }
            }
         }

         template <typename T>
         inline T process(const operator_type operation, const T arg)
         {
            return exprtk::details::numeric::details::process_impl(operation,arg);
         }

         template <typename T>
         inline T process(const operator_type operation, const T arg0, const T arg1)
         {
            return exprtk::details::numeric::details::process_impl(operation, arg0, arg1);
         }
      }

      template <typename Node>
      struct node_collector_interface
      {
         typedef Node* node_ptr_t;
         typedef Node** node_pp_t;
         typedef std::vector<node_pp_t> noderef_list_t;

         virtual ~node_collector_interface()
         {}

         virtual void collect_nodes(noderef_list_t&)
         {}
      };

      template <typename Node>
      struct node_depth_base;

      template <typename T>
      class expression_node : public node_collector_interface<expression_node<T> >
                            , public node_depth_base<expression_node<T> >
      {
      public:

         enum node_type
         {
            e_none          , e_null          , e_constant    , e_unary        ,
            e_binary        , e_binary_ext    , e_trinary     , e_quaternary   ,
            e_vararg        , e_conditional   , e_while       , e_repeat       ,
            e_for           , e_switch        , e_mswitch     , e_return       ,
            e_retenv        , e_variable      , e_stringvar   , e_stringconst  ,
            e_stringvarrng  , e_cstringvarrng , e_strgenrange , e_strconcat    ,
            e_stringvarsize , e_strswap       , e_stringsize  , e_stringvararg ,
            e_function      , e_vafunction    , e_genfunction , e_strfunction  ,
            e_strcondition  , e_strccondition , e_add         , e_sub          ,
            e_mul           , e_div           , e_mod         , e_pow          ,
            e_lt            , e_lte           , e_gt          , e_gte          ,
            e_eq            , e_ne            , e_and         , e_nand         ,
            e_or            , e_nor           , e_xor         , e_xnor         ,
            e_in            , e_like          , e_ilike       , e_inranges     ,
            e_ipow          , e_ipowinv       , e_abs         , e_acos         ,
            e_acosh         , e_asin          , e_asinh       , e_atan         ,
            e_atanh         , e_ceil          , e_cos         , e_cosh         ,
            e_exp           , e_expm1         , e_floor       , e_log          ,
            e_log10         , e_log2          , e_log1p       , e_neg          ,
            e_pos           , e_round         , e_sin         , e_sinc         ,
            e_sinh          , e_sqrt          , e_tan         , e_tanh         ,
            e_cot           , e_sec           , e_csc         , e_r2d          ,
            e_d2r           , e_d2g           , e_g2d         , e_notl         ,
            e_sgn           , e_erf           , e_erfc        , e_ncdf         ,
            e_frac          , e_trunc         , e_uvouv       , e_vov          ,
            e_cov           , e_voc           , e_vob         , e_bov          ,
            e_cob           , e_boc           , e_vovov       , e_vovoc        ,
            e_vocov         , e_covov         , e_covoc       , e_vovovov      ,
            e_vovovoc       , e_vovocov       , e_vocovov     , e_covovov      ,
            e_covocov       , e_vocovoc       , e_covovoc     , e_vococov      ,
            e_sf3ext        , e_sf4ext        , e_nulleq      , e_strass       ,
            e_vector        , e_vecsize       , e_vecelem     , e_veccelem     ,
            e_vecelemrtc    , e_veccelemrtc   , e_rbvecelem   , e_rbvecelemrtc ,
            e_rbveccelem    , e_rbveccelemrtc , e_vecinit     , e_vecvalass    ,
            e_vecvecass     , e_vecopvalass   , e_vecopvecass , e_vecfunc      ,
            e_vecvecswap    , e_vecvecineq    , e_vecvalineq  , e_valvecineq   ,
            e_vecvecarith   , e_vecvalarith   , e_valvecarith , e_vecunaryop   ,
            e_vecondition   , e_break         , e_continue    , e_swap         ,
            e_assert
         };

         typedef T value_type;
         typedef expression_node<T>* expression_ptr;
         typedef node_collector_interface<expression_node<T> > nci_t;
         typedef typename nci_t::noderef_list_t noderef_list_t;
         typedef node_depth_base<expression_node<T> > ndb_t;

         virtual ~expression_node()
         {}

         inline virtual T value() const
         {
            return std::numeric_limits<T>::quiet_NaN();
         }

         inline virtual expression_node<T>* branch(const std::size_t& index = 0) const
         {
            return reinterpret_cast<expression_ptr>(index * 0);
         }

         inline virtual node_type type() const
         {
            return e_none;
         }

         inline virtual bool valid() const
         {
            return true;
         }
      }; // class expression_node

      template <typename T>
      inline bool is_generally_string_node(const expression_node<T>* node);

      inline bool is_true(const double v)
      {
         return std::not_equal_to<double>()(0.0,v);
      }

      inline bool is_true(const long double v)
      {
         return std::not_equal_to<long double>()(0.0L,v);
      }

      inline bool is_true(const float v)
      {
         return std::not_equal_to<float>()(0.0f,v);
      }

      template <typename T>
      inline bool is_true(const expression_node<T>* node)
      {
         return std::not_equal_to<T>()(T(0),node->value());
      }

      template <typename T>
      inline bool is_true(const std::pair<expression_node<T>*,bool>& node)
      {
         return std::not_equal_to<T>()(T(0),node.first->value());
      }

      template <typename T>
      inline bool is_false(const expression_node<T>* node)
      {
         return std::equal_to<T>()(T(0),node->value());
      }

      template <typename T>
      inline bool is_false(const std::pair<expression_node<T>*,bool>& node)
      {
         return std::equal_to<T>()(T(0),node.first->value());
      }

      template <typename T>
      inline bool is_literal_node(const expression_node<T>* node)
      {
         return node && (details::expression_node<T>::e_constant == node->type());
      }

      template <typename T>
      inline bool is_unary_node(const expression_node<T>* node)
      {
         return node && (details::expression_node<T>::e_unary == node->type());
      }

      template <typename T>
      inline bool is_neg_unary_node(const expression_node<T>* node)
      {
         return node && (details::expression_node<T>::e_neg == node->type());
      }

      template <typename T>
      inline bool is_binary_node(const expression_node<T>* node)
      {
         return node && (details::expression_node<T>::e_binary == node->type());
      }

      template <typename T>
      inline bool is_variable_node(const expression_node<T>* node)
      {
         return node && (details::expression_node<T>::e_variable == node->type());
      }

      template <typename T>
      inline bool is_ivariable_node(const expression_node<T>* node)
      {
         return node &&
                (
                  details::expression_node<T>::e_variable      == node->type() ||
                  details::expression_node<T>::e_vecelem       == node->type() ||
                  details::expression_node<T>::e_veccelem      == node->type() ||
                  details::expression_node<T>::e_vecelemrtc    == node->type() ||
                  details::expression_node<T>::e_veccelemrtc   == node->type() ||
                  details::expression_node<T>::e_rbvecelem     == node->type() ||
                  details::expression_node<T>::e_rbveccelem    == node->type() ||
                  details::expression_node<T>::e_rbvecelemrtc  == node->type() ||
                  details::expression_node<T>::e_rbveccelemrtc == node->type()
                );
      }

      template <typename T>
      inline bool is_vector_elem_node(const expression_node<T>* node)
      {
         return node && (details::expression_node<T>::e_vecelem == node->type());
      }

      template <typename T>
      inline bool is_vector_celem_node(const expression_node<T>* node)
      {
         return node && (details::expression_node<T>::e_veccelem == node->type());
      }

      template <typename T>
      inline bool is_vector_elem_rtc_node(const expression_node<T>* node)
      {
         return node && (details::expression_node<T>::e_vecelemrtc == node->type());
      }

      template <typename T>
      inline bool is_vector_celem_rtc_node(const expression_node<T>* node)
      {
         return node && (details::expression_node<T>::e_veccelemrtc == node->type());
      }

      template <typename T>
      inline bool is_rebasevector_elem_node(const expression_node<T>* node)
      {
         return node && (details::expression_node<T>::e_rbvecelem == node->type());
      }

      template <typename T>
      inline bool is_rebasevector_elem_rtc_node(const expression_node<T>* node)
      {
         return node && (details::expression_node<T>::e_rbvecelemrtc == node->type());
      }

      template <typename T>
      inline bool is_rebasevector_celem_rtc_node(const expression_node<T>* node)
      {
         return node && (details::expression_node<T>::e_rbveccelemrtc == node->type());
      }

      template <typename T>
      inline bool is_rebasevector_celem_node(const expression_node<T>* node)
      {
         return node && (details::expression_node<T>::e_rbveccelem == node->type());
      }

      template <typename T>
      inline bool is_vector_node(const expression_node<T>* node)
      {
         return node && (details::expression_node<T>::e_vector == node->type());
      }

      template <typename T>
      inline bool is_ivector_node(const expression_node<T>* node)
      {
         if (node)
         {
            switch (node->type())
            {
               case details::expression_node<T>::e_vector      :
               case details::expression_node<T>::e_vecvalass   :
               case details::expression_node<T>::e_vecvecass   :
               case details::expression_node<T>::e_vecopvalass :
               case details::expression_node<T>::e_vecopvecass :
               case details::expression_node<T>::e_vecvecswap  :
               case details::expression_node<T>::e_vecvecarith :
               case details::expression_node<T>::e_vecvalarith :
               case details::expression_node<T>::e_valvecarith :
               case details::expression_node<T>::e_vecunaryop  :
               case details::expression_node<T>::e_vecondition : return true;
               default                                         : return false;
            }
         }
         else
            return false;
      }

      template <typename T>
      inline bool is_constant_node(const expression_node<T>* node)
      {
         return node &&
         (
           details::expression_node<T>::e_constant    == node->type() ||
           details::expression_node<T>::e_stringconst == node->type()
         );
      }

      template <typename T>
      inline bool is_null_node(const expression_node<T>* node)
      {
         return node && (details::expression_node<T>::e_null == node->type());
      }

      template <typename T>
      inline bool is_break_node(const expression_node<T>* node)
      {
         return node && (details::expression_node<T>::e_break == node->type());
      }

      template <typename T>
      inline bool is_continue_node(const expression_node<T>* node)
      {
         return node && (details::expression_node<T>::e_continue == node->type());
      }

      template <typename T>
      inline bool is_swap_node(const expression_node<T>* node)
      {
         return node && (details::expression_node<T>::e_swap == node->type());
      }

      template <typename T>
      inline bool is_function(const expression_node<T>* node)
      {
         return node && (details::expression_node<T>::e_function == node->type());
      }

      template <typename T>
      inline bool is_vararg_node(const expression_node<T>* node)
      {
         return node && (details::expression_node<T>::e_vararg == node->type());
      }

      template <typename T>
      inline bool is_return_node(const expression_node<T>* node)
      {
         return node && (details::expression_node<T>::e_return == node->type());
      }

      template <typename T> class unary_node;

      template <typename T>
      inline bool is_negate_node(const expression_node<T>* node)
      {
         if (node && is_unary_node(node))
         {
            return (details::e_neg == static_cast<const unary_node<T>*>(node)->operation());
         }
         else
            return false;
      }

      template <typename T>
      inline bool is_assert_node(const expression_node<T>* node)
      {
         return node && (details::expression_node<T>::e_assert == node->type());
      }

      template <typename T>
      inline bool branch_deletable(const expression_node<T>* node)
      {
         return (0 != node)             &&
                !is_variable_node(node) &&
                !is_string_node  (node) ;
      }

      template <std::size_t N, typename T>
      inline bool all_nodes_valid(expression_node<T>* const (&b)[N])
      {
         for (std::size_t i = 0; i < N; ++i)
         {
            if (0 == b[i]) return false;
         }

         return true;
      }

      template <typename T,
                typename Allocator,
                template <typename, typename> class Sequence>
      inline bool all_nodes_valid(const Sequence<expression_node<T>*,Allocator>& b)
      {
         for (std::size_t i = 0; i < b.size(); ++i)
         {
            if (0 == b[i]) return false;
         }

         return true;
      }

      template <std::size_t N, typename T>
      inline bool all_nodes_variables(expression_node<T>* const (&b)[N])
      {
         for (std::size_t i = 0; i < N; ++i)
         {
            if (0 == b[i])
               return false;
            else if (!is_variable_node(b[i]))
               return false;
         }

         return true;
      }

      template <typename T,
                typename Allocator,
                template <typename, typename> class Sequence>
      inline bool all_nodes_variables(const Sequence<expression_node<T>*,Allocator>& b)
      {
         for (std::size_t i = 0; i < b.size(); ++i)
         {
            if (0 == b[i])
               return false;
            else if (!is_variable_node(b[i]))
               return false;
         }

         return true;
      }

      template <typename Node>
      class node_collection_destructor
      {
      public:

         typedef node_collector_interface<Node> nci_t;

         typedef typename nci_t::node_ptr_t     node_ptr_t;
         typedef typename nci_t::node_pp_t      node_pp_t;
         typedef typename nci_t::noderef_list_t noderef_list_t;

         static void delete_nodes(node_ptr_t& root)
         {
            std::vector<node_pp_t> node_delete_list;
            node_delete_list.reserve(1000);

            collect_nodes(root, node_delete_list);

            for (std::size_t i = 0; i < node_delete_list.size(); ++i)
            {
               node_ptr_t& node = *node_delete_list[i];
               exprtk_debug(("ncd::delete_nodes() - deleting: %p\n", reinterpret_cast<void*>(node)));
               delete node;
               node = reinterpret_cast<node_ptr_t>(0);
            }
         }

      private:

         static void collect_nodes(node_ptr_t& root, noderef_list_t& node_delete_list)
         {
            std::deque<node_ptr_t> node_list;
            node_list.push_back(root);
            node_delete_list.push_back(&root);

            noderef_list_t child_node_delete_list;
            child_node_delete_list.reserve(1000);

            while (!node_list.empty())
            {
               node_list.front()->collect_nodes(child_node_delete_list);

               if (!child_node_delete_list.empty())
               {
                  for (std::size_t i = 0; i < child_node_delete_list.size(); ++i)
                  {
                     node_pp_t& node = child_node_delete_list[i];

                     if (0 == (*node))
                     {
                        exprtk_debug(("ncd::collect_nodes() - null node encountered.\n"));
                     }

                     node_list.push_back(*node);
                  }

                  node_delete_list.insert(
                     node_delete_list.end(),
                     child_node_delete_list.begin(), child_node_delete_list.end());

                  child_node_delete_list.clear();
               }

               node_list.pop_front();
            }

            std::reverse(node_delete_list.begin(), node_delete_list.end());
         }
      };

      template <typename NodeAllocator, typename T, std::size_t N>
      inline void free_all_nodes(NodeAllocator& node_allocator, expression_node<T>* (&b)[N])
      {
         for (std::size_t i = 0; i < N; ++i)
         {
            free_node(node_allocator,b[i]);
         }
      }

      template <typename NodeAllocator,
                typename T,
                typename Allocator,
                template <typename, typename> class Sequence>
      inline void free_all_nodes(NodeAllocator& node_allocator, Sequence<expression_node<T>*,Allocator>& b)
      {
         for (std::size_t i = 0; i < b.size(); ++i)
         {
            free_node(node_allocator,b[i]);
         }

         b.clear();
      }

      template <typename NodeAllocator, typename T>
      inline void free_node(NodeAllocator&, expression_node<T>*& node)
      {
         if ((0 == node) || is_variable_node(node) || is_string_node(node))
         {
            return;
         }

         node_collection_destructor<expression_node<T> >
            ::delete_nodes(node);
      }

      template <typename T>
      inline void destroy_node(expression_node<T>*& node)
      {
         if (0 != node)
         {
            node_collection_destructor<expression_node<T> >
               ::delete_nodes(node);
         }
      }

      template <typename Node>
      struct node_depth_base
      {
         typedef Node* node_ptr_t;
         typedef std::pair<node_ptr_t,bool> nb_pair_t;

         node_depth_base()
         : depth_set(false)
         , depth(0)
         {}

         virtual ~node_depth_base()
         {}

         virtual std::size_t node_depth() const { return 1; }

         std::size_t compute_node_depth(const Node* const& node) const
         {
            if (!depth_set)
            {
               depth = 1 + (node ? node->node_depth() : 0);
               depth_set = true;
            }

            return depth;
         }

         std::size_t compute_node_depth(const nb_pair_t& branch) const
         {
            if (!depth_set)
            {
               depth = 1 + (branch.first ? branch.first->node_depth() : 0);
               depth_set = true;
            }

            return depth;
         }

         template <std::size_t N>
         std::size_t compute_node_depth(const nb_pair_t (&branch)[N]) const
         {
            if (!depth_set)
            {
               depth = 0;

               for (std::size_t i = 0; i < N; ++i)
               {
                  if (branch[i].first)
                  {
                     depth = std::max(depth,branch[i].first->node_depth());
                  }
               }

               depth += 1;
               depth_set = true;
            }

            return depth;
         }

         template <typename BranchType>
         std::size_t max_node_depth(const BranchType& n0, const BranchType& n1) const
         {
            return std::max(compute_node_depth(n0), compute_node_depth(n1));
         }

         template <typename BranchType>
         std::size_t max_node_depth(const BranchType& n0, const BranchType& n1, const BranchType& n2) const
         {
            return std::max(compute_node_depth(n0),
                   std::max(compute_node_depth(n1), compute_node_depth(n2)));
         }

         template <typename BranchType>
         std::size_t max_node_depth(const BranchType& n0, const BranchType& n1,
                                    const BranchType& n2, const BranchType& n3) const
         {
            return std::max(
                     std::max(compute_node_depth(n0), compute_node_depth(n1)),
                     std::max(compute_node_depth(n2), compute_node_depth(n3)));
         }

         template <typename BranchType>
         std::size_t compute_node_depth(const BranchType& n0, const BranchType& n1) const
         {
            if (!depth_set)
            {
               depth = 1 + max_node_depth(n0, n1);
               depth_set = true;
            }

            return depth;
         }

         template <typename BranchType>
         std::size_t compute_node_depth(const BranchType& n0, const BranchType& n1,
                                        const BranchType& n2) const
         {
            if (!depth_set)
            {
               depth = 1 + max_node_depth(n0, n1, n2);
               depth_set = true;
            }

            return depth;
         }

         template <typename BranchType>
         std::size_t compute_node_depth(const BranchType& n0, const BranchType& n1,
                                        const BranchType& n2, const BranchType& n3) const
         {
            if (!depth_set)
            {
               depth = 1 + max_node_depth(n0, n1, n2, n3);
               depth_set = true;
            }

            return depth;
         }

         template <typename Allocator,
                   template <typename, typename> class Sequence>
         std::size_t compute_node_depth(const Sequence<node_ptr_t, Allocator>& branch_list) const
         {
            if (!depth_set)
            {
               for (std::size_t i = 0; i < branch_list.size(); ++i)
               {
                  if (branch_list[i])
                  {
                     depth = std::max(depth, compute_node_depth(branch_list[i]));
                  }
               }

               depth_set = true;
            }

            return depth;
         }

         template <typename Allocator,
                   template <typename, typename> class Sequence>
         std::size_t compute_node_depth(const Sequence<nb_pair_t,Allocator>& branch_list) const
         {
            if (!depth_set)
            {
               for (std::size_t i = 0; i < branch_list.size(); ++i)
               {
                  if (branch_list[i].first)
                  {
                     depth = std::max(depth, compute_node_depth(branch_list[i].first));
                  }
               }

               depth_set = true;
            }

            return depth;
         }

         mutable bool depth_set;
         mutable std::size_t depth;

         template <typename NodeSequence>
         void collect(node_ptr_t const& node,
                      const bool deletable,
                      NodeSequence& delete_node_list) const
         {
            if ((0 != node) && deletable)
            {
               delete_node_list.push_back(const_cast<node_ptr_t*>(&node));
            }
         }

         template <typename NodeSequence>
         void collect(const nb_pair_t& branch,
                      NodeSequence& delete_node_list) const
         {
            collect(branch.first, branch.second, delete_node_list);
         }

         template <typename NodeSequence>
         void collect(Node*& node,
                      NodeSequence& delete_node_list) const
         {
            collect(node, branch_deletable(node), delete_node_list);
         }

         template <std::size_t N, typename NodeSequence>
         void collect(const nb_pair_t(&branch)[N],
                      NodeSequence& delete_node_list) const
         {
            for (std::size_t i = 0; i < N; ++i)
            {
               collect(branch[i].first, branch[i].second, delete_node_list);
            }
         }

         template <typename Allocator,
                   template <typename, typename> class Sequence,
                   typename NodeSequence>
         void collect(const Sequence<nb_pair_t, Allocator>& branch,
                      NodeSequence& delete_node_list) const
         {
            for (std::size_t i = 0; i < branch.size(); ++i)
            {
               collect(branch[i].first, branch[i].second, delete_node_list);
            }
         }

         template <typename Allocator,
                   template <typename, typename> class Sequence,
                   typename NodeSequence>
         void collect(const Sequence<node_ptr_t, Allocator>& branch_list,
                      NodeSequence& delete_node_list) const
         {
            for (std::size_t i = 0; i < branch_list.size(); ++i)
            {
               collect(branch_list[i], branch_deletable(branch_list[i]), delete_node_list);
            }
         }

         template <typename Boolean,
                   typename AllocatorT,
                   typename AllocatorB,
                   template <typename, typename> class Sequence,
                   typename NodeSequence>
         void collect(const Sequence<node_ptr_t, AllocatorT>& branch_list,
                      const Sequence<Boolean, AllocatorB>& branch_deletable_list,
                      NodeSequence& delete_node_list) const
         {
            for (std::size_t i = 0; i < branch_list.size(); ++i)
            {
               collect(branch_list[i], branch_deletable_list[i], delete_node_list);
            }
         }
      };

      template <typename Type>
      class vector_holder
      {
      private:

         typedef Type value_type;
         typedef value_type* value_ptr;
         typedef const value_ptr const_value_ptr;
         typedef vector_holder<Type> vector_holder_t;

         class vector_holder_base
         {
         public:

            virtual ~vector_holder_base()
            {}

            inline value_ptr operator[](const std::size_t& index) const
            {
               return value_at(index);
            }

            inline std::size_t size() const
            {
               return vector_size();
            }

            inline std::size_t base_size() const
            {
               return vector_base_size();
            }

            inline value_ptr data() const
            {
               return value_at(0);
            }

            virtual inline bool rebaseable() const
            {
               return false;
            }

            virtual void set_ref(value_ptr*)
            {}

            virtual void remove_ref(value_ptr*)
            {}

            virtual vector_view<Type>* rebaseable_instance()
            {
               return reinterpret_cast<vector_view<Type>*>(0);
            }

         protected:

            virtual value_ptr value_at(const std::size_t&) const = 0;
            virtual std::size_t vector_size()              const = 0;
            virtual std::size_t vector_base_size()         const = 0;
         };

         class array_vector_impl exprtk_final : public vector_holder_base
         {
         public:

            array_vector_impl(const Type* vec, const std::size_t& vec_size)
            : vec_(vec)
            , size_(vec_size)
            {}

         protected:

            value_ptr value_at(const std::size_t& index) const exprtk_override
            {
               assert(index < size_);
               return const_cast<const_value_ptr>(vec_ + index);
            }

            std::size_t vector_size() const exprtk_override
            {
               return size_;
            }

            std::size_t vector_base_size() const exprtk_override
            {
               return vector_size();
            }

         private:

            array_vector_impl(const array_vector_impl&) exprtk_delete;
            array_vector_impl& operator=(const array_vector_impl&) exprtk_delete;

            const Type* vec_;
            const std::size_t size_;
         };

         template <typename Allocator,
                   template <typename, typename> class Sequence>
         class sequence_vector_impl exprtk_final : public vector_holder_base
         {
         public:

            typedef Sequence<Type,Allocator> sequence_t;

            explicit sequence_vector_impl(sequence_t& seq)
            : sequence_(seq)
            {}

         protected:

            value_ptr value_at(const std::size_t& index) const exprtk_override
            {
               assert(index < sequence_.size());
               return (&sequence_[index]);
            }

            std::size_t vector_size() const exprtk_override
            {
               return sequence_.size();
            }

            std::size_t vector_base_size() const exprtk_override
            {
               return vector_size();
            }

         private:

            sequence_vector_impl(const sequence_vector_impl&) exprtk_delete;
            sequence_vector_impl& operator=(const sequence_vector_impl&) exprtk_delete;

            sequence_t& sequence_;
         };

         class vector_view_impl exprtk_final : public vector_holder_base
         {
         public:

            typedef exprtk::vector_view<Type> vector_view_t;

            explicit vector_view_impl(vector_view_t& vec_view)
            : vec_view_(vec_view)
            {
               assert(vec_view_.size() > 0);
            }

            void set_ref(value_ptr* ref) exprtk_override
            {
               vec_view_.set_ref(ref);
            }

            void remove_ref(value_ptr* ref) exprtk_override
            {
               vec_view_.remove_ref(ref);
            }

            bool rebaseable() const exprtk_override
            {
               return true;
            }

            vector_view<Type>* rebaseable_instance() exprtk_override
            {
               return &vec_view_;
            }

         protected:

            value_ptr value_at(const std::size_t& index) const exprtk_override
            {
               assert(index < vec_view_.size());
               return (&vec_view_[index]);
            }

            std::size_t vector_size() const exprtk_override
            {
               return vec_view_.size();
            }

            std::size_t vector_base_size() const exprtk_override
            {
               return vec_view_.base_size();
            }

         private:

            vector_view_impl(const vector_view_impl&) exprtk_delete;
            vector_view_impl& operator=(const vector_view_impl&) exprtk_delete;

            vector_view_t& vec_view_;
         };

         class resizable_vector_impl exprtk_final : public vector_holder_base
         {
         public:

            resizable_vector_impl(vector_holder& vec_view_holder,
                                  const Type* vec,
                                  const std::size_t& vec_size)
            : vec_(vec)
            , size_(vec_size)
            , vec_view_holder_(*vec_view_holder.rebaseable_instance())
            {
               assert(vec_view_holder.rebaseable_instance());
               assert(size_ <= vector_base_size());
            }

            virtual ~resizable_vector_impl() exprtk_override
            {}

         protected:

            value_ptr value_at(const std::size_t& index) const exprtk_override
            {
               assert(index < vector_size());
               return const_cast<const_value_ptr>(vec_ + index);
            }

            std::size_t vector_size() const exprtk_override
            {
               return vec_view_holder_.size();
            }

            std::size_t vector_base_size() const exprtk_override
            {
               return vec_view_holder_.base_size();
            }

            bool rebaseable() const exprtk_override
            {
               return true;
            }

            virtual vector_view<Type>* rebaseable_instance() exprtk_override
            {
               return &vec_view_holder_;
            }

         private:

            resizable_vector_impl(const resizable_vector_impl&) exprtk_delete;
            resizable_vector_impl& operator=(const resizable_vector_impl&) exprtk_delete;

            const Type* vec_;
            const std::size_t size_;
            vector_view<Type>& vec_view_holder_;
         };

      public:

         typedef typename details::vec_data_store<Type> vds_t;

         vector_holder(Type* vec, const std::size_t& vec_size)
         : vector_holder_base_(new(buffer)array_vector_impl(vec,vec_size))
         {}

         explicit vector_holder(const vds_t& vds)
         : vector_holder_base_(new(buffer)array_vector_impl(vds.data(),vds.size()))
         {}

         template <typename Allocator>
         explicit vector_holder(std::vector<Type,Allocator>& vec)
         : vector_holder_base_(new(buffer)sequence_vector_impl<Allocator,std::vector>(vec))
         {}

         explicit vector_holder(exprtk::vector_view<Type>& vec)
         : vector_holder_base_(new(buffer)vector_view_impl(vec))
         {}

         explicit vector_holder(vector_holder_t& vec_holder, const vds_t& vds)
         : vector_holder_base_(new(buffer)resizable_vector_impl(vec_holder, vds.data(), vds.size()))
         {}

         inline value_ptr operator[](const std::size_t& index) const
         {
            return (*vector_holder_base_)[index];
         }

         inline std::size_t size() const
         {
            return vector_holder_base_->size();
         }

         inline std::size_t base_size() const
         {
            return vector_holder_base_->base_size();
         }

         inline value_ptr data() const
         {
            return vector_holder_base_->data();
         }

         void set_ref(value_ptr* ref)
         {
            if (rebaseable())
            {
               vector_holder_base_->set_ref(ref);
            }
         }

         void remove_ref(value_ptr* ref)
         {
            if (rebaseable())
            {
               vector_holder_base_->remove_ref(ref);
            }
         }

         bool rebaseable() const
         {
            return vector_holder_base_->rebaseable();
         }

         vector_view<Type>* rebaseable_instance()
         {
            return vector_holder_base_->rebaseable_instance();
         }

      private:

         vector_holder(const vector_holder<Type>&) exprtk_delete;
         vector_holder<Type>& operator=(const vector_holder<Type>&) exprtk_delete;

         mutable vector_holder_base* vector_holder_base_;
         uchar_t buffer[64];
      };

      template <typename T>
      class null_node exprtk_final : public expression_node<T>
      {
      public:

         inline T value() const exprtk_override
         {
            return std::numeric_limits<T>::quiet_NaN();
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_null;
         }
      };

      template <typename T, std::size_t N>
      inline void construct_branch_pair(std::pair<expression_node<T>*,bool> (&branch)[N],
                                        expression_node<T>* b,
                                        const std::size_t& index)
      {
         if (b && (index < N))
         {
            branch[index] = std::make_pair(b,branch_deletable(b));
         }
      }

      template <typename T>
      inline void construct_branch_pair(std::pair<expression_node<T>*,bool>& branch, expression_node<T>* b)
      {
         if (b)
         {
            branch = std::make_pair(b,branch_deletable(b));
         }
      }

      template <std::size_t N, typename T>
      inline void init_branches(std::pair<expression_node<T>*,bool> (&branch)[N],
                                expression_node<T>* b0,
                                expression_node<T>* b1 = reinterpret_cast<expression_node<T>*>(0),
                                expression_node<T>* b2 = reinterpret_cast<expression_node<T>*>(0),
                                expression_node<T>* b3 = reinterpret_cast<expression_node<T>*>(0),
                                expression_node<T>* b4 = reinterpret_cast<expression_node<T>*>(0),
                                expression_node<T>* b5 = reinterpret_cast<expression_node<T>*>(0),
                                expression_node<T>* b6 = reinterpret_cast<expression_node<T>*>(0),
                                expression_node<T>* b7 = reinterpret_cast<expression_node<T>*>(0),
                                expression_node<T>* b8 = reinterpret_cast<expression_node<T>*>(0),
                                expression_node<T>* b9 = reinterpret_cast<expression_node<T>*>(0))
      {
         construct_branch_pair(branch, b0, 0);
         construct_branch_pair(branch, b1, 1);
         construct_branch_pair(branch, b2, 2);
         construct_branch_pair(branch, b3, 3);
         construct_branch_pair(branch, b4, 4);
         construct_branch_pair(branch, b5, 5);
         construct_branch_pair(branch, b6, 6);
         construct_branch_pair(branch, b7, 7);
         construct_branch_pair(branch, b8, 8);
         construct_branch_pair(branch, b9, 9);
      }

      template <typename T>
      class null_eq_node exprtk_final : public expression_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         typedef std::pair<expression_ptr,bool> branch_t;

         explicit null_eq_node(expression_ptr branch, const bool equality = true)
         : equality_(equality)
         {
            construct_branch_pair(branch_, branch);
            assert(valid());
         }

         inline T value() const exprtk_override
         {
            const T v = branch_.first->value();
            const bool result = details::numeric::is_nan(v);

            if (result)
               return equality_ ? T(1) : T(0);
            else
               return equality_ ? T(0) : T(1);
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_nulleq;
         }

         inline expression_node<T>* branch(const std::size_t&) const exprtk_override
         {
            return branch_.first;
         }

         inline bool valid() const exprtk_override
         {
            return branch_.first;
         }

         void collect_nodes(typename expression_node<T>::noderef_list_t& node_delete_list) exprtk_override
         {
            expression_node<T>::ndb_t::collect(branch_, node_delete_list);
         }

         std::size_t node_depth() const exprtk_override
         {
            return expression_node<T>::ndb_t::compute_node_depth(branch_);
         }

      private:

         bool equality_;
         branch_t branch_;
      };

      template <typename T>
      class literal_node exprtk_final : public expression_node<T>
      {
      public:

         explicit literal_node(const T& v)
         : value_(v)
         {}

         inline T value() const exprtk_override
         {
            return value_;
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_constant;
         }

         inline expression_node<T>* branch(const std::size_t&) const exprtk_override
         {
            return reinterpret_cast<expression_node<T>*>(0);
         }

      private:

         literal_node(const literal_node<T>&) exprtk_delete;
         literal_node<T>& operator=(const literal_node<T>&) exprtk_delete;

         const T value_;
      };

      template <typename T>
      struct range_pack;

      template <typename T>
      struct range_data_type;

      template <typename T>
      class range_interface
      {
      public:

         typedef range_pack<T> range_t;

         virtual ~range_interface()
         {}

         virtual range_t& range_ref() = 0;

         virtual const range_t& range_ref() const = 0;
      };

      #ifndef exprtk_disable_string_capabilities
      template <typename T>
      class string_base_node
      {
      public:

         typedef range_data_type<T> range_data_type_t;

         virtual ~string_base_node()
         {}

         virtual std::string str () const = 0;

         virtual char_cptr   base() const = 0;

         virtual std::size_t size() const = 0;
      };

      template <typename T>
      class string_literal_node exprtk_final
                                : public expression_node <T>
                                , public string_base_node<T>
                                , public range_interface <T>
      {
      public:

         typedef range_pack<T> range_t;

         explicit string_literal_node(const std::string& v)
         : value_(v)
         {
            rp_.n0_c = std::make_pair<bool,std::size_t>(true, 0);
            rp_.n1_c = std::make_pair<bool,std::size_t>(true, v.size());
            rp_.cache.first  = rp_.n0_c.second;
            rp_.cache.second = rp_.n1_c.second;
         }

         inline T value() const exprtk_override
         {
            return std::numeric_limits<T>::quiet_NaN();
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_stringconst;
         }

         inline expression_node<T>* branch(const std::size_t&) const exprtk_override
         {
            return reinterpret_cast<expression_node<T>*>(0);
         }

         std::string str() const exprtk_override
         {
            return value_;
         }

         char_cptr base() const exprtk_override
         {
            return value_.data();
         }

         std::size_t size() const exprtk_override
         {
            return value_.size();
         }

         range_t& range_ref() exprtk_override
         {
            return rp_;
         }

         const range_t& range_ref() const exprtk_override
         {
            return rp_;
         }

      private:

         string_literal_node(const string_literal_node<T>&) exprtk_delete;
         string_literal_node<T>& operator=(const string_literal_node<T>&) exprtk_delete;

         const std::string value_;
         range_t rp_;
      };
      #endif

      template <typename T>
      class unary_node : public expression_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         typedef std::pair<expression_ptr,bool> branch_t;

         unary_node(const operator_type& opr, expression_ptr branch)
         : operation_(opr)
         {
            construct_branch_pair(branch_,branch);
            assert(valid());
         }

         inline T value() const exprtk_override
         {
            return numeric::process<T>
                     (operation_,branch_.first->value());
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_unary;
         }

         inline operator_type operation()
         {
            return operation_;
         }

         inline expression_node<T>* branch(const std::size_t&) const exprtk_override
         {
            return branch_.first;
         }

         inline bool valid() const exprtk_override
         {
            return branch_.first && branch_.first->valid();
         }

         inline void release()
         {
            branch_.second = false;
         }

         void collect_nodes(typename expression_node<T>::noderef_list_t& node_delete_list) exprtk_override
         {
            expression_node<T>::ndb_t::collect(branch_, node_delete_list);
         }

         std::size_t node_depth() const exprtk_final
         {
            return expression_node<T>::ndb_t::compute_node_depth(branch_);
         }

      private:

         operator_type operation_;
         branch_t branch_;
      };

      template <typename T>
      class binary_node : public expression_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         typedef std::pair<expression_ptr,bool> branch_t;

         binary_node(const operator_type& opr,
                     expression_ptr branch0,
                     expression_ptr branch1)
         : operation_(opr)
         {
            init_branches<2>(branch_, branch0, branch1);
            assert(valid());
         }

         inline T value() const exprtk_override
         {
            return numeric::process<T>
                   (
                      operation_,
                      branch_[0].first->value(),
                      branch_[1].first->value()
                   );
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_binary;
         }

         inline operator_type operation()
         {
            return operation_;
         }

         inline expression_node<T>* branch(const std::size_t& index = 0) const exprtk_override
         {
            assert(index < 2);
            return branch_[index].first;
         }

         inline bool valid() const exprtk_override
         {
            return
               branch_[0].first && branch_[0].first->valid() &&
               branch_[1].first && branch_[1].first->valid() ;
         }

         void collect_nodes(typename expression_node<T>::noderef_list_t& node_delete_list) exprtk_override
         {
            expression_node<T>::ndb_t::collect(branch_, node_delete_list);
         }

         std::size_t node_depth() const exprtk_final
         {
            return expression_node<T>::ndb_t::template compute_node_depth<2>(branch_);
         }

      private:

         operator_type operation_;
         branch_t branch_[2];
      };

      template <typename T, typename Operation>
      class binary_ext_node exprtk_final : public expression_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         typedef std::pair<expression_ptr,bool> branch_t;

         binary_ext_node(expression_ptr branch0, expression_ptr branch1)
         {
            init_branches<2>(branch_, branch0, branch1);
            assert(valid());
         }

         inline T value() const exprtk_override
         {
            const T arg0 = branch_[0].first->value();
            const T arg1 = branch_[1].first->value();
            return Operation::process(arg0,arg1);
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_binary_ext;
         }

         inline operator_type operation()
         {
            return Operation::operation();
         }

         inline expression_node<T>* branch(const std::size_t& index = 0) const exprtk_override
         {
            assert(index < 2);
            return branch_[index].first;
         }

         inline bool valid() const exprtk_override
         {
            return
               branch_[0].first && branch_[0].first->valid() &&
               branch_[1].first && branch_[1].first->valid() ;
         }

         void collect_nodes(typename expression_node<T>::noderef_list_t& node_delete_list) exprtk_override
         {
            expression_node<T>::ndb_t::collect(branch_, node_delete_list);
         }

         std::size_t node_depth() const exprtk_override
         {
            return expression_node<T>::ndb_t::template compute_node_depth<2>(branch_);
         }

      protected:

         branch_t branch_[2];
      };

      template <typename T>
      class trinary_node : public expression_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         typedef std::pair<expression_ptr,bool> branch_t;

         trinary_node(const operator_type& opr,
                      expression_ptr branch0,
                      expression_ptr branch1,
                      expression_ptr branch2)
         : operation_(opr)
         {
            init_branches<3>(branch_, branch0, branch1, branch2);
            assert(valid());
         }

         inline T value() const exprtk_override
         {
            const T arg0 = branch_[0].first->value();
            const T arg1 = branch_[1].first->value();
            const T arg2 = branch_[2].first->value();

            switch (operation_)
            {
               case e_inrange : return (arg1 < arg0) ? T(0) : ((arg1 > arg2) ? T(0) : T(1));

               case e_clamp   : return (arg1 < arg0) ? arg0 : (arg1 > arg2 ? arg2 : arg1);

               case e_iclamp  : if ((arg1 <= arg0) || (arg1 >= arg2))
                                   return arg1;
                                else
                                   return ((T(2) * arg1  <= (arg2 + arg0)) ? arg0 : arg2);

               default        : exprtk_debug(("trinary_node::value() - Error: Invalid operation\n"));
                                return std::numeric_limits<T>::quiet_NaN();
            }
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_trinary;
         }

         inline bool valid() const exprtk_override
         {
            return
               branch_[0].first && branch_[0].first->valid() &&
               branch_[1].first && branch_[1].first->valid() &&
               branch_[2].first && branch_[2].first->valid() ;
         }

         void collect_nodes(typename expression_node<T>::noderef_list_t& node_delete_list) exprtk_override
         {
            expression_node<T>::ndb_t::collect(branch_, node_delete_list);
         }

         std::size_t node_depth() const exprtk_override exprtk_final
         {
            return expression_node<T>::ndb_t::template compute_node_depth<3>(branch_);
         }

      protected:

         operator_type operation_;
         branch_t branch_[3];
      };

      template <typename T>
      class quaternary_node : public expression_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         typedef std::pair<expression_ptr,bool> branch_t;

         quaternary_node(const operator_type& opr,
                         expression_ptr branch0,
                         expression_ptr branch1,
                         expression_ptr branch2,
                         expression_ptr branch3)
         : operation_(opr)
         {
            init_branches<4>(branch_, branch0, branch1, branch2, branch3);
         }

         inline T value() const exprtk_override
         {
            return std::numeric_limits<T>::quiet_NaN();
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_quaternary;
         }

         void collect_nodes(typename expression_node<T>::noderef_list_t& node_delete_list) exprtk_override
         {
            expression_node<T>::ndb_t::collect(branch_, node_delete_list);
         }

         std::size_t node_depth() const exprtk_override exprtk_final
         {
            return expression_node<T>::ndb_t::template compute_node_depth<4>(branch_);
         }

         inline bool valid() const exprtk_override
         {
            return
               branch_[0].first && branch_[0].first->valid() &&
               branch_[1].first && branch_[1].first->valid() &&
               branch_[2].first && branch_[2].first->valid() &&
               branch_[3].first && branch_[3].first->valid() ;
         }

      protected:

         operator_type operation_;
         branch_t branch_[4];
      };

      template <typename T>
      class conditional_node exprtk_final : public expression_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         typedef std::pair<expression_ptr,bool> branch_t;

         conditional_node(expression_ptr condition,
                          expression_ptr consequent,
                          expression_ptr alternative)
         {
            construct_branch_pair(condition_  , condition  );
            construct_branch_pair(consequent_ , consequent );
            construct_branch_pair(alternative_, alternative);
            assert(valid());
         }

         inline T value() const exprtk_override
         {
            if (is_true(condition_))
               return consequent_.first->value();
            else
               return alternative_.first->value();
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_conditional;
         }

         inline bool valid() const exprtk_override
         {
            return
               condition_  .first && condition_  .first->valid() &&
               consequent_ .first && consequent_ .first->valid() &&
               alternative_.first && alternative_.first->valid() ;
         }

         void collect_nodes(typename expression_node<T>::noderef_list_t& node_delete_list) exprtk_override
         {
            expression_node<T>::ndb_t::collect(condition_   , node_delete_list);
            expression_node<T>::ndb_t::collect(consequent_  , node_delete_list);
            expression_node<T>::ndb_t::collect(alternative_ , node_delete_list);
         }

         std::size_t node_depth() const exprtk_override
         {
            return expression_node<T>::ndb_t::compute_node_depth
               (condition_, consequent_, alternative_);
         }

      private:

         branch_t condition_;
         branch_t consequent_;
         branch_t alternative_;
      };

      template <typename T>
      class cons_conditional_node exprtk_final : public expression_node<T>
      {
      public:

         // Consequent only conditional statement node
         typedef expression_node<T>* expression_ptr;
         typedef std::pair<expression_ptr,bool> branch_t;

         cons_conditional_node(expression_ptr condition,
                               expression_ptr consequent)
         {
            construct_branch_pair(condition_ , condition );
            construct_branch_pair(consequent_, consequent);
            assert(valid());
         }

         inline T value() const exprtk_override
         {
            if (is_true(condition_))
               return consequent_.first->value();
            else
               return std::numeric_limits<T>::quiet_NaN();
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_conditional;
         }

         inline bool valid() const exprtk_override
         {
            return
               condition_ .first && condition_ .first->valid() &&
               consequent_.first && consequent_.first->valid() ;
         }

         void collect_nodes(typename expression_node<T>::noderef_list_t& node_delete_list) exprtk_override
         {
            expression_node<T>::ndb_t::collect(condition_  , node_delete_list);
            expression_node<T>::ndb_t::collect(consequent_ , node_delete_list);
         }

         std::size_t node_depth() const exprtk_override
         {
            return expression_node<T>::ndb_t::
               compute_node_depth(condition_, consequent_);
         }

      private:

         branch_t condition_;
         branch_t consequent_;
      };

      #ifndef exprtk_disable_break_continue
      template <typename T>
      class break_exception
      {
      public:

         explicit break_exception(const T& v)
         : value(v)
         {}

         T value;
      };

      class continue_exception {};

      template <typename T>
      class break_node exprtk_final : public expression_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         typedef std::pair<expression_ptr,bool> branch_t;

         explicit break_node(expression_ptr ret = expression_ptr(0))
         {
            construct_branch_pair(return_, ret);
         }

         inline T value() const exprtk_override
         {
            const T result = return_.first ?
                             return_.first->value() :
                             std::numeric_limits<T>::quiet_NaN();

            throw break_exception<T>(result);

            #if !defined(_MSC_VER) && !defined(__NVCOMPILER)
            return std::numeric_limits<T>::quiet_NaN();
            #endif
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_break;
         }

         void collect_nodes(typename expression_node<T>::noderef_list_t& node_delete_list) exprtk_override
         {
            expression_node<T>::ndb_t::collect(return_, node_delete_list);
         }

         std::size_t node_depth() const exprtk_override
         {
            return expression_node<T>::ndb_t::compute_node_depth(return_);
         }

      private:

         branch_t return_;
      };

      template <typename T>
      class continue_node exprtk_final : public expression_node<T>
      {
      public:

         inline T value() const exprtk_override
         {
            throw continue_exception();
            #if !defined(_MSC_VER) && !defined(__NVCOMPILER)
            return std::numeric_limits<T>::quiet_NaN();
            #endif
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_break;
         }
      };
      #endif

      struct loop_runtime_checker
      {
         loop_runtime_checker(loop_runtime_check_ptr loop_runtime_check,
                              loop_runtime_check::loop_types lp_typ = loop_runtime_check::e_invalid)
         : iteration_count_(0)
         , loop_runtime_check_(loop_runtime_check)
         , max_loop_iterations_(loop_runtime_check_->max_loop_iterations)
         , loop_type_(lp_typ)
         {
            assert(loop_runtime_check_);
         }

         inline void reset(const _uint64_t initial_value = 0) const
         {
            iteration_count_ = initial_value;
         }

         inline bool check() const
         {
            assert(loop_runtime_check_);

            if (
                 (++iteration_count_ <= max_loop_iterations_) &&
                 loop_runtime_check_->check()
               )
            {
               return true;
            }

            loop_runtime_check::violation_context ctxt;
            ctxt.loop      = loop_type_;
            ctxt.violation = loop_runtime_check::e_iteration_count;

            loop_runtime_check_->handle_runtime_violation(ctxt);

            return false;
         }

         bool valid() const
         {
            return 0 != loop_runtime_check_;
         }

         mutable _uint64_t iteration_count_;
         mutable loop_runtime_check_ptr loop_runtime_check_;
         const details::_uint64_t& max_loop_iterations_;
         loop_runtime_check::loop_types loop_type_;
      };

      template <typename T>
      class while_loop_node : public expression_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         typedef std::pair<expression_ptr,bool> branch_t;

         while_loop_node(expression_ptr condition,
                         expression_ptr loop_body)
         {
            construct_branch_pair(condition_, condition);
            construct_branch_pair(loop_body_, loop_body);
            assert(valid());
         }

         inline T value() const exprtk_override
         {
            T result = T(0);

            while (is_true(condition_))
            {
               result = loop_body_.first->value();
            }

            return result;
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_while;
         }

         inline bool valid() const exprtk_override
         {
            return
               condition_.first && condition_.first->valid() &&
               loop_body_.first && loop_body_.first->valid() ;
         }

         void collect_nodes(typename expression_node<T>::noderef_list_t& node_delete_list) exprtk_override
         {
            expression_node<T>::ndb_t::collect(condition_ , node_delete_list);
            expression_node<T>::ndb_t::collect(loop_body_ , node_delete_list);
         }

         std::size_t node_depth() const exprtk_override
         {
            return expression_node<T>::ndb_t::compute_node_depth(condition_, loop_body_);
         }

      protected:

         branch_t condition_;
         branch_t loop_body_;
      };

      template <typename T>
      class while_loop_rtc_node exprtk_final
                                : public while_loop_node<T>
                                , public loop_runtime_checker
      {
      public:

         typedef while_loop_node<T>  parent_t;
         typedef expression_node<T>* expression_ptr;

         while_loop_rtc_node(expression_ptr condition,
                             expression_ptr loop_body,
                             loop_runtime_check_ptr loop_rt_chk)
         : parent_t(condition, loop_body)
         , loop_runtime_checker(loop_rt_chk, loop_runtime_check::e_while_loop)
         {
            assert(valid());
         }

         inline T value() const exprtk_override
         {

            T result = T(0);

            loop_runtime_checker::reset();

            while (is_true(parent_t::condition_) && loop_runtime_checker::check())
            {
               result = parent_t::loop_body_.first->value();
            }

            return result;
         }

         using parent_t::valid;

         bool valid() const exprtk_override exprtk_final
         {
            return parent_t::valid() &&
                   loop_runtime_checker::valid();
         }
      };

      template <typename T>
      class repeat_until_loop_node : public expression_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         typedef std::pair<expression_ptr,bool> branch_t;

         repeat_until_loop_node(expression_ptr condition,
                                expression_ptr loop_body)
         {
            construct_branch_pair(condition_, condition);
            construct_branch_pair(loop_body_, loop_body);
            assert(valid());
         }

         inline T value() const exprtk_override
         {
            T result = T(0);

            do
            {
               result = loop_body_.first->value();
            }
            while (is_false(condition_.first));

            return result;
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_repeat;
         }

         inline bool valid() const exprtk_override
         {
            return
               condition_.first && condition_.first->valid() &&
               loop_body_.first && loop_body_.first->valid() ;
         }

         void collect_nodes(typename expression_node<T>::noderef_list_t& node_delete_list) exprtk_override
         {
            expression_node<T>::ndb_t::collect(condition_ , node_delete_list);
            expression_node<T>::ndb_t::collect(loop_body_ , node_delete_list);
         }

         std::size_t node_depth() const exprtk_override
         {
            return expression_node<T>::ndb_t::compute_node_depth(condition_, loop_body_);
         }

      protected:

         branch_t condition_;
         branch_t loop_body_;
      };

      template <typename T>
      class repeat_until_loop_rtc_node exprtk_final
                                       : public repeat_until_loop_node<T>
                                       , public loop_runtime_checker
      {
      public:

         typedef repeat_until_loop_node<T> parent_t;
         typedef expression_node<T>*       expression_ptr;

         repeat_until_loop_rtc_node(expression_ptr condition,
                                    expression_ptr loop_body,
                                    loop_runtime_check_ptr loop_rt_chk)
         : parent_t(condition, loop_body)
         , loop_runtime_checker(loop_rt_chk, loop_runtime_check::e_repeat_until_loop)
         {
            assert(valid());
         }

         inline T value() const exprtk_override
         {
            T result = T(0);

            loop_runtime_checker::reset(1);

            do
            {
               result = parent_t::loop_body_.first->value();
            }
            while (is_false(parent_t::condition_.first) && loop_runtime_checker::check());

            return result;
         }

         using parent_t::valid;

         inline bool valid() const exprtk_override exprtk_final
         {
            return parent_t::valid() &&
                   loop_runtime_checker::valid();
         }
      };

      template <typename T>
      class for_loop_node : public expression_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         typedef std::pair<expression_ptr,bool> branch_t;

         for_loop_node(expression_ptr initialiser,
                       expression_ptr condition,
                       expression_ptr incrementor,
                       expression_ptr loop_body)
         {
            construct_branch_pair(initialiser_, initialiser);
            construct_branch_pair(condition_  , condition  );
            construct_branch_pair(incrementor_, incrementor);
            construct_branch_pair(loop_body_  , loop_body  );
            assert(valid());
         }

         inline T value() const exprtk_override
         {
            T result = T(0);

            if (initialiser_.first)
               initialiser_.first->value();

            if (incrementor_.first)
            {
               while (is_true(condition_))
               {
                  result = loop_body_.first->value();
                  incrementor_.first->value();
               }
            }
            else
            {
               while (is_true(condition_))
               {
                  result = loop_body_.first->value();
               }
            }

            return result;
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_for;
         }

         inline bool valid() const exprtk_override
         {
            return condition_.first && loop_body_.first;
         }

         void collect_nodes(typename expression_node<T>::noderef_list_t& node_delete_list) exprtk_override
         {
            expression_node<T>::ndb_t::collect(initialiser_ , node_delete_list);
            expression_node<T>::ndb_t::collect(condition_   , node_delete_list);
            expression_node<T>::ndb_t::collect(incrementor_ , node_delete_list);
            expression_node<T>::ndb_t::collect(loop_body_   , node_delete_list);
         }

         std::size_t node_depth() const exprtk_override
         {
            return expression_node<T>::ndb_t::compute_node_depth
               (initialiser_, condition_, incrementor_, loop_body_);
         }

      protected:

         branch_t initialiser_;
         branch_t condition_  ;
         branch_t incrementor_;
         branch_t loop_body_  ;
      };

      template <typename T>
      class for_loop_rtc_node exprtk_final
                              : public for_loop_node<T>
                              , public loop_runtime_checker
      {
      public:

         typedef for_loop_node<T>    parent_t;
         typedef expression_node<T>* expression_ptr;

         for_loop_rtc_node(expression_ptr initialiser,
                           expression_ptr condition,
                           expression_ptr incrementor,
                           expression_ptr loop_body,
                           loop_runtime_check_ptr loop_rt_chk)
         : parent_t(initialiser, condition, incrementor, loop_body)
         , loop_runtime_checker(loop_rt_chk, loop_runtime_check::e_for_loop)
         {
            assert(valid());
         }

         inline T value() const exprtk_override
         {
            T result = T(0);

            loop_runtime_checker::reset();

            if (parent_t::initialiser_.first)
               parent_t::initialiser_.first->value();

            if (parent_t::incrementor_.first)
            {
               while (is_true(parent_t::condition_) && loop_runtime_checker::check())
               {
                  result = parent_t::loop_body_.first->value();
                  parent_t::incrementor_.first->value();
               }
            }
            else
            {
               while (is_true(parent_t::condition_) && loop_runtime_checker::check())
               {
                  result = parent_t::loop_body_.first->value();
               }
            }

            return result;
         }

         using parent_t::valid;

         inline bool valid() const exprtk_override exprtk_final
         {
            return parent_t::valid() &&
                   loop_runtime_checker::valid();
         }
      };

      #ifndef exprtk_disable_break_continue
      template <typename T>
      class while_loop_bc_node : public while_loop_node<T>
      {
      public:

         typedef while_loop_node<T>  parent_t;
         typedef expression_node<T>* expression_ptr;

         while_loop_bc_node(expression_ptr condition,
                            expression_ptr loop_body)
         : parent_t(condition, loop_body)
         {
            assert(parent_t::valid());
         }

         inline T value() const exprtk_override
         {
            T result = T(0);

            while (is_true(parent_t::condition_))
            {
               try
               {
                  result = parent_t::loop_body_.first->value();
               }
               catch(const break_exception<T>& e)
               {
                  return e.value;
               }
               catch(const continue_exception&)
               {}
            }

            return result;
         }
      };

      template <typename T>
      class while_loop_bc_rtc_node exprtk_final
                                   : public while_loop_bc_node<T>
                                   , public loop_runtime_checker
      {
      public:

         typedef while_loop_bc_node<T> parent_t;
         typedef expression_node<T>*   expression_ptr;

         while_loop_bc_rtc_node(expression_ptr condition,
                                expression_ptr loop_body,
                                loop_runtime_check_ptr loop_rt_chk)
         : parent_t(condition, loop_body)
         , loop_runtime_checker(loop_rt_chk, loop_runtime_check::e_while_loop)
         {
            assert(valid());
         }

         inline T value() const exprtk_override
         {
            T result = T(0);

            loop_runtime_checker::reset();

            while (is_true(parent_t::condition_) && loop_runtime_checker::check())
            {
               try
               {
                  result = parent_t::loop_body_.first->value();
               }
               catch(const break_exception<T>& e)
               {
                  return e.value;
               }
               catch(const continue_exception&)
               {}
            }

            return result;
         }

         using parent_t::valid;

         inline bool valid() const exprtk_override exprtk_final
         {
            return parent_t::valid() &&
                   loop_runtime_checker::valid();
         }
      };

      template <typename T>
      class repeat_until_loop_bc_node : public repeat_until_loop_node<T>
      {
      public:

         typedef repeat_until_loop_node<T> parent_t;
         typedef expression_node<T>*       expression_ptr;

         repeat_until_loop_bc_node(expression_ptr condition,
                                   expression_ptr loop_body)
         : parent_t(condition, loop_body)
         {
            assert(parent_t::valid());
         }

         inline T value() const exprtk_override
         {
            T result = T(0);

            do
            {
               try
               {
                  result = parent_t::loop_body_.first->value();
               }
               catch(const break_exception<T>& e)
               {
                  return e.value;
               }
               catch(const continue_exception&)
               {}
            }
            while (is_false(parent_t::condition_.first));

            return result;
         }
      };

      template <typename T>
      class repeat_until_loop_bc_rtc_node exprtk_final
                                          : public repeat_until_loop_bc_node<T>
                                          , public loop_runtime_checker
      {
      public:

         typedef repeat_until_loop_bc_node<T> parent_t;
         typedef expression_node<T>*          expression_ptr;

         repeat_until_loop_bc_rtc_node(expression_ptr condition,
                                       expression_ptr loop_body,
                                       loop_runtime_check_ptr loop_rt_chk)
         : parent_t(condition, loop_body)
         , loop_runtime_checker(loop_rt_chk, loop_runtime_check::e_repeat_until_loop)
         {
            assert(valid());
         }

         inline T value() const exprtk_override
         {
            T result = T(0);

            loop_runtime_checker::reset();

            do
            {
               try
               {
                  result = parent_t::loop_body_.first->value();
               }
               catch(const break_exception<T>& e)
               {
                  return e.value;
               }
               catch(const continue_exception&)
               {}
            }
            while (is_false(parent_t::condition_.first) && loop_runtime_checker::check());

            return result;
         }

         using parent_t::valid;

         inline bool valid() const exprtk_override exprtk_final
         {
            return parent_t::valid() &&
                   loop_runtime_checker::valid();
         }
      };

      template <typename T>
      class for_loop_bc_node : public for_loop_node<T>
      {
      public:

         typedef for_loop_node<T>    parent_t;
         typedef expression_node<T>* expression_ptr;

         for_loop_bc_node(expression_ptr initialiser,
                          expression_ptr condition,
                          expression_ptr incrementor,
                          expression_ptr loop_body)
         : parent_t(initialiser, condition, incrementor, loop_body)
         {
            assert(parent_t::valid());
         }

         inline T value() const exprtk_override
         {
            T result = T(0);

            if (parent_t::initialiser_.first)
               parent_t::initialiser_.first->value();

            if (parent_t::incrementor_.first)
            {
               while (is_true(parent_t::condition_))
               {
                  try
                  {
                     result = parent_t::loop_body_.first->value();
                  }
                  catch(const break_exception<T>& e)
                  {
                     return e.value;
                  }
                  catch(const continue_exception&)
                  {}

                  parent_t::incrementor_.first->value();
               }
            }
            else
            {
               while (is_true(parent_t::condition_))
               {
                  try
                  {
                     result = parent_t::loop_body_.first->value();
                  }
                  catch(const break_exception<T>& e)
                  {
                     return e.value;
                  }
                  catch(const continue_exception&)
                  {}
               }
            }

            return result;
         }
      };

      template <typename T>
      class for_loop_bc_rtc_node exprtk_final
                                 : public for_loop_bc_node<T>
                                 , public loop_runtime_checker
      {
      public:

         typedef for_loop_bc_node<T> parent_t;
         typedef expression_node<T>* expression_ptr;

         for_loop_bc_rtc_node(expression_ptr initialiser,
                              expression_ptr condition,
                              expression_ptr incrementor,
                              expression_ptr loop_body,
                              loop_runtime_check_ptr loop_rt_chk)
         : parent_t(initialiser, condition, incrementor, loop_body)
         , loop_runtime_checker(loop_rt_chk, loop_runtime_check::e_for_loop)
         {
            assert(valid());
         }

         inline T value() const exprtk_override
         {
            T result = T(0);

            loop_runtime_checker::reset();

            if (parent_t::initialiser_.first)
               parent_t::initialiser_.first->value();

            if (parent_t::incrementor_.first)
            {
               while (is_true(parent_t::condition_) && loop_runtime_checker::check())
               {
                  try
                  {
                     result = parent_t::loop_body_.first->value();
                  }
                  catch(const break_exception<T>& e)
                  {
                     return e.value;
                  }
                  catch(const continue_exception&)
                  {}

                  parent_t::incrementor_.first->value();
               }
            }
            else
            {
               while (is_true(parent_t::condition_) && loop_runtime_checker::check())
               {
                  try
                  {
                     result = parent_t::loop_body_.first->value();
                  }
                  catch(const break_exception<T>& e)
                  {
                     return e.value;
                  }
                  catch(const continue_exception&)
                  {}
               }
            }

            return result;
         }

         using parent_t::valid;

         inline bool valid() const exprtk_override exprtk_final
         {
            return parent_t::valid() &&
                   loop_runtime_checker::valid();
         }
      };
      #endif

      template <typename T>
      class switch_node : public expression_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         typedef std::pair<expression_ptr,bool> branch_t;

         template <typename Allocator,
                   template <typename, typename> class Sequence>
         explicit switch_node(const Sequence<expression_ptr,Allocator>& arg_list)
         {
            if (1 != (arg_list.size() & 1))
               return;

            arg_list_.resize(arg_list.size());

            for (std::size_t i = 0; i < arg_list.size(); ++i)
            {
               if (arg_list[i] && arg_list[i]->valid())
               {
                  construct_branch_pair(arg_list_[i], arg_list[i]);
               }
               else
               {
                  arg_list_.clear();
                  return;
               }
            }

            assert(valid());
         }

         inline T value() const exprtk_override
         {
            const std::size_t upper_bound = (arg_list_.size() - 1);

            for (std::size_t i = 0; i < upper_bound; i += 2)
            {
               expression_ptr condition  = arg_list_[i    ].first;
               expression_ptr consequent = arg_list_[i + 1].first;

               if (is_true(condition))
               {
                  return consequent->value();
               }
            }

            return arg_list_[upper_bound].first->value();
         }

         inline typename expression_node<T>::node_type type() const exprtk_override exprtk_final
         {
            return expression_node<T>::e_switch;
         }

         inline bool valid() const exprtk_override
         {
            return !arg_list_.empty();
         }

         void collect_nodes(typename expression_node<T>::noderef_list_t& node_delete_list) exprtk_override
         {
            expression_node<T>::ndb_t::collect(arg_list_, node_delete_list);
         }

         std::size_t node_depth() const exprtk_override exprtk_final
         {
            return expression_node<T>::ndb_t::compute_node_depth(arg_list_);
         }

      protected:

         std::vector<branch_t> arg_list_;
      };

      template <typename T, typename Switch_N>
      class switch_n_node exprtk_final : public switch_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;

         template <typename Allocator,
                   template <typename, typename> class Sequence>
         explicit switch_n_node(const Sequence<expression_ptr,Allocator>& arg_list)
         : switch_node<T>(arg_list)
         {}

         inline T value() const exprtk_override
         {
            return Switch_N::process(switch_node<T>::arg_list_);
         }
      };

      template <typename T>
      class multi_switch_node exprtk_final : public expression_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         typedef std::pair<expression_ptr,bool> branch_t;

         template <typename Allocator,
                   template <typename, typename> class Sequence>
         explicit multi_switch_node(const Sequence<expression_ptr,Allocator>& arg_list)
         {
            if (0 != (arg_list.size() & 1))
               return;

            arg_list_.resize(arg_list.size());

            for (std::size_t i = 0; i < arg_list.size(); ++i)
            {
               if (arg_list[i] && arg_list[i]->valid())
               {
                  construct_branch_pair(arg_list_[i], arg_list[i]);
               }
               else
               {
                  arg_list_.clear();
                  return;
               }
            }

            assert(valid());
         }

         inline T value() const exprtk_override
         {
            const std::size_t upper_bound = (arg_list_.size() - 1);

            T result = T(0);

            for (std::size_t i = 0; i < upper_bound; i += 2)
            {
               expression_ptr condition  = arg_list_[i    ].first;
               expression_ptr consequent = arg_list_[i + 1].first;

               if (is_true(condition))
               {
                  result = consequent->value();
               }
            }

            return result;
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_mswitch;
         }

         inline bool valid() const exprtk_override
         {
            return !arg_list_.empty() && (0 == (arg_list_.size() % 2));
         }

         void collect_nodes(typename expression_node<T>::noderef_list_t& node_delete_list) exprtk_override
         {
            expression_node<T>::ndb_t::collect(arg_list_, node_delete_list);
         }

         std::size_t node_depth() const exprtk_override exprtk_final
         {
            return expression_node<T>::ndb_t::compute_node_depth(arg_list_);
         }

      private:

         std::vector<branch_t> arg_list_;
      };

      template <typename T>
      class ivariable
      {
      public:

         virtual ~ivariable()
         {}

         virtual T& ref() = 0;
         virtual const T& ref() const = 0;
      };

      template <typename T>
      class variable_node exprtk_final
                          : public expression_node<T>
                          , public ivariable      <T>
      {
      public:

         static T null_value;

         explicit variable_node()
         : value_(&null_value)
         {}

         explicit variable_node(T& v)
         : value_(&v)
         {}

         inline bool operator <(const variable_node<T>& v) const
         {
            return this < (&v);
         }

         inline T value() const exprtk_override
         {
            return (*value_);
         }

         inline T& ref() exprtk_override
         {
            return (*value_);
         }

         inline const T& ref() const exprtk_override
         {
            return (*value_);
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_variable;
         }

      private:

         T* value_;
      };

      template <typename T>
      T variable_node<T>::null_value = T(std::numeric_limits<T>::quiet_NaN());

      template <typename T>
      struct range_pack
      {
         typedef expression_node<T>*           expression_node_ptr;
         typedef std::pair<std::size_t,std::size_t> cached_range_t;

         range_pack()
         : n0_e (std::make_pair(false,expression_node_ptr(0)))
         , n1_e (std::make_pair(false,expression_node_ptr(0)))
         , n0_c (std::make_pair(false,0))
         , n1_c (std::make_pair(false,0))
         , cache(std::make_pair(0,0))
         {}

         void clear()
         {
            n0_e  = std::make_pair(false,expression_node_ptr(0));
            n1_e  = std::make_pair(false,expression_node_ptr(0));
            n0_c  = std::make_pair(false,0);
            n1_c  = std::make_pair(false,0);
            cache = std::make_pair(0,0);
         }

         void free()
         {
            if (n0_e.first && n0_e.second)
            {
               n0_e.first = false;

               if (
                    !is_variable_node(n0_e.second) &&
                    !is_string_node  (n0_e.second)
                  )
               {
                  destroy_node(n0_e.second);
               }
            }

            if (n1_e.first && n1_e.second)
            {
               n1_e.first = false;

               if (
                    !is_variable_node(n1_e.second) &&
                    !is_string_node  (n1_e.second)
                  )
               {
                  destroy_node(n1_e.second);
               }
            }
         }

         bool const_range() const
         {
           return ( n0_c.first &&  n1_c.first) &&
                  (!n0_e.first && !n1_e.first);
         }

         bool var_range() const
         {
           return ( n0_e.first &&  n1_e.first) &&
                  (!n0_c.first && !n1_c.first);
         }

         bool operator() (std::size_t& r0, std::size_t& r1,
                          const std::size_t& size = std::numeric_limits<std::size_t>::max()) const
         {
            if (n0_c.first)
               r0 = n0_c.second;
            else if (n0_e.first)
            {
               r0 = static_cast<std::size_t>(details::numeric::to_int64(n0_e.second->value()));
            }
            else
               return false;

            if (n1_c.first)
               r1 = n1_c.second;
            else if (n1_e.first)
            {
               r1 = static_cast<std::size_t>(details::numeric::to_int64(n1_e.second->value()));
            }
            else
               return false;

            if (
                 (std::numeric_limits<std::size_t>::max() != size) &&
                 (std::numeric_limits<std::size_t>::max() == r1  )
               )
            {
               r1 = size;
            }

            cache.first  = r0;
            cache.second = r1;

            #ifndef exprtk_enable_range_runtime_checks
            return (r0 <= r1);
            #else
            return range_runtime_check(r0, r1, size);
            #endif
         }

         inline std::size_t const_size() const
         {
            return (n1_c.second - n0_c.second);
         }

         inline std::size_t cache_size() const
         {
            return (cache.second - cache.first);
         }

         std::pair<bool,expression_node_ptr> n0_e;
         std::pair<bool,expression_node_ptr> n1_e;
         std::pair<bool,std::size_t        > n0_c;
         std::pair<bool,std::size_t        > n1_c;
         mutable cached_range_t             cache;

         #ifdef exprtk_enable_range_runtime_checks
         bool range_runtime_check(const std::size_t r0,
                                  const std::size_t r1,
                                  const std::size_t size) const
         {
            if (r0 > size)
            {
               throw std::runtime_error("range error: (r0 < 0) || (r0 > size)");
               #if !defined(_MSC_VER) && !defined(__NVCOMPILER)
               return false;
               #endif
            }

            if (r1 > size)
            {
               throw std::runtime_error("range error: (r1 < 0) || (r1 > size)");
               #if !defined(_MSC_VER) && !defined(__NVCOMPILER)
               return false;
               #endif
            }

            return (r0 <= r1);
         }
         #endif
      };

      template <typename T>
      class string_base_node;

      template <typename T>
      struct range_data_type
      {
         typedef range_pack<T> range_t;
         typedef string_base_node<T>* strbase_ptr_t;

         range_data_type()
         : range(0)
         , data (0)
         , size (0)
         , type_size(0)
         , str_node (0)
         {}

         range_t*      range;
         void*         data;
         std::size_t   size;
         std::size_t   type_size;
         strbase_ptr_t str_node;
      };

      template <typename T> class vector_node;

      template <typename T>
      class vector_interface
      {
      public:

         typedef vector_node<T>*   vector_node_ptr;
         typedef vec_data_store<T> vds_t;

         virtual ~vector_interface()
         {}

         virtual std::size_t size     () const = 0;

         virtual std::size_t base_size() const = 0;

         virtual vector_node_ptr vec  () const = 0;

         virtual vector_node_ptr vec  ()       = 0;

         virtual       vds_t& vds     ()       = 0;

         virtual const vds_t& vds     () const = 0;

         virtual bool side_effect     () const { return false; }
      };

      template <typename T>
      class vector_node exprtk_final
                        : public expression_node <T>
                        , public vector_interface<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         typedef vector_holder<T>    vector_holder_t;
         typedef vector_node<T>*     vector_node_ptr;
         typedef vec_data_store<T>   vds_t;

         explicit vector_node(vector_holder_t* vh)
         : vector_holder_(vh)
         , vds_((*vector_holder_).size(),(*vector_holder_)[0])
         {
            vector_holder_->set_ref(&vds_.ref());
         }

         vector_node(const vds_t& vds, vector_holder_t* vh)
         : vector_holder_(vh)
         , vds_(vds)
         {}

        ~vector_node() exprtk_override
         {
            assert(valid());
            vector_holder_->remove_ref(&vds_.ref());
         }

         inline T value() const exprtk_override
         {
            return vds().data()[0];
         }

         vector_node_ptr vec() const exprtk_override
         {
            return const_cast<vector_node_ptr>(this);
         }

         vector_node_ptr vec() exprtk_override
         {
            return this;
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_vector;
         }

         inline bool valid() const exprtk_override
         {
            return vector_holder_;
         }

         std::size_t size() const exprtk_override
         {
            return vec_holder().size();
         }

         std::size_t base_size() const exprtk_override
         {
            return vec_holder().base_size();
         }

         vds_t& vds() exprtk_override
         {
            return vds_;
         }

         const vds_t& vds() const exprtk_override
         {
            return vds_;
         }

         inline vector_holder_t& vec_holder()
         {
            return (*vector_holder_);
         }

         inline vector_holder_t& vec_holder() const
         {
            return (*vector_holder_);
         }

      private:

         vector_holder_t* vector_holder_;
         vds_t                      vds_;
      };

      template <typename T>
      class vector_size_node exprtk_final
                        : public expression_node <T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         typedef vector_holder<T>    vector_holder_t;

         explicit vector_size_node(vector_holder_t* vh)
         : vector_holder_(vh)
         {}

        ~vector_size_node() exprtk_override
         {
            assert(valid());
         }

         inline T value() const exprtk_override
         {
            assert(vector_holder_);
            return static_cast<T>(vector_holder_->size());
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_vecsize;
         }

         inline bool valid() const exprtk_override
         {
            return vector_holder_ && vector_holder_->size();
         }

         inline vector_holder_t* vec_holder()
         {
            return vector_holder_;
         }

      private:

         vector_holder_t* vector_holder_;
      };

      template <typename T>
      class vector_elem_node exprtk_final
                             : public expression_node<T>
                             , public ivariable      <T>
      {
      public:

         typedef expression_node<T>*            expression_ptr;
         typedef vector_holder<T>               vector_holder_t;
         typedef vector_holder_t*               vector_holder_ptr;
         typedef std::pair<expression_ptr,bool> branch_t;

         vector_elem_node(expression_ptr vec_node,
                          expression_ptr index,
                          vector_holder_ptr vec_holder)
         : vector_holder_(vec_holder)
         , vector_base_((*vec_holder)[0])
         {
            construct_branch_pair(vector_node_, vec_node);
            construct_branch_pair(index_      , index   );
            assert(valid());
         }

         inline T value() const exprtk_override
         {
            return *access_vector();
         }

         inline T& ref() exprtk_override
         {
            return *access_vector();
         }

         inline const T& ref() const exprtk_override
         {
            return *access_vector();
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_vecelem;
         }

         inline bool valid() const exprtk_override
         {
            return
               vector_holder_        &&
               index_.first          &&
               vector_node_.first    &&
               index_.first->valid() &&
               vector_node_.first->valid();
         }

         inline vector_holder_t& vec_holder()
         {
            return (*vector_holder_);
         }

         void collect_nodes(typename expression_node<T>::noderef_list_t& node_delete_list) exprtk_override
         {
            expression_node<T>::ndb_t::collect(vector_node_, node_delete_list);
            expression_node<T>::ndb_t::collect(index_      , node_delete_list);
         }

         std::size_t node_depth() const exprtk_override
         {
            return expression_node<T>::ndb_t::compute_node_depth
               (vector_node_, index_);
         }

      private:

         inline T* access_vector() const
         {
            vector_node_.first->value();
            return (vector_base_ + details::numeric::to_uint64(index_.first->value()));
         }

         vector_holder_ptr vector_holder_;
         T* vector_base_;
         branch_t vector_node_;
         branch_t index_;
      };

      template <typename T>
      class vector_celem_node exprtk_final
                              : public expression_node<T>
                              , public ivariable      <T>
      {
      public:

         typedef expression_node<T>*            expression_ptr;
         typedef vector_holder<T>               vector_holder_t;
         typedef vector_holder_t*               vector_holder_ptr;
         typedef std::pair<expression_ptr,bool> branch_t;

         vector_celem_node(expression_ptr vec_node,
                           const std::size_t index,
                           vector_holder_ptr vec_holder)
         : index_(index)
         , vector_holder_(vec_holder)
         , vector_base_((*vec_holder)[0])
         {
            construct_branch_pair(vector_node_, vec_node);
            assert(valid());
         }

         inline T value() const exprtk_override
         {
            return *access_vector();
         }

         inline T& ref() exprtk_override
         {
            return *access_vector();
         }

         inline const T& ref() const exprtk_override
         {
            return *access_vector();
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_veccelem;
         }

         inline bool valid() const exprtk_override
         {
            return
               vector_holder_     &&
               vector_node_.first &&
               vector_node_.first->valid();
         }

         inline vector_holder_t& vec_holder()
         {
            return (*vector_holder_);
         }

         void collect_nodes(typename expression_node<T>::noderef_list_t& node_delete_list) exprtk_override
         {
            expression_node<T>::ndb_t::collect(vector_node_, node_delete_list);
         }

         std::size_t node_depth() const exprtk_override
         {
            return expression_node<T>::ndb_t::compute_node_depth(vector_node_);
         }

      private:

         inline T* access_vector() const
         {
            vector_node_.first->value();
            return (vector_base_ + index_);
         }

         const std::size_t index_;
         vector_holder_ptr vector_holder_;
         T* vector_base_;
         branch_t vector_node_;
      };

      template <typename T>
      class vector_elem_rtc_node exprtk_final
                                 : public expression_node<T>
                                 , public ivariable      <T>
      {
      public:

         typedef expression_node<T>*            expression_ptr;
         typedef vector_holder<T>               vector_holder_t;
         typedef vector_holder_t*               vector_holder_ptr;
         typedef std::pair<expression_ptr,bool> branch_t;

         vector_elem_rtc_node(expression_ptr vec_node,
                              expression_ptr index,
                              vector_holder_ptr vec_holder,
                              vector_access_runtime_check_ptr vec_rt_chk)
         : vector_holder_(vec_holder)
         , vector_base_((*vec_holder)[0])
         , vec_rt_chk_(vec_rt_chk)
         , max_vector_index_(vector_holder_->size() - 1)
         {
            construct_branch_pair(vector_node_, vec_node);
            construct_branch_pair(index_      , index   );
            assert(valid());
         }

         inline T value() const exprtk_override
         {
            return *access_vector();
         }

         inline T& ref() exprtk_override
         {
            return *access_vector();
         }

         inline const T& ref() const exprtk_override
         {
            return *access_vector();
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_vecelemrtc;
         }

         inline bool valid() const exprtk_override
         {
            return
               vector_holder_        &&
               index_.first          &&
               vector_node_.first    &&
               index_.first->valid() &&
               vector_node_.first->valid();
         }

         inline vector_holder_t& vec_holder()
         {
            return (*vector_holder_);
         }

         void collect_nodes(typename expression_node<T>::noderef_list_t& node_delete_list) exprtk_override
         {
            expression_node<T>::ndb_t::collect(vector_node_, node_delete_list);
            expression_node<T>::ndb_t::collect(index_,       node_delete_list);
         }

         std::size_t node_depth() const exprtk_override
         {
            return expression_node<T>::ndb_t::compute_node_depth
               (vector_node_, index_);
         }

      private:

         inline T* access_vector() const
         {
            const _uint64_t index = details::numeric::to_uint64(index_.first->value());
            vector_node_.first->value();

            if (index <= max_vector_index_)
            {
               return (vector_holder_->data() + index);
            }

            assert(vec_rt_chk_);

            vector_access_runtime_check::violation_context context;
            context.base_ptr   = reinterpret_cast<void*>(vector_base_);
            context.end_ptr    = reinterpret_cast<void*>(vector_base_ + vector_holder_->size());
            context.access_ptr = reinterpret_cast<void*>(vector_base_ + index);
            context.type_size  = sizeof(T);

            return vec_rt_chk_->handle_runtime_violation(context) ?
               reinterpret_cast<T*>(context.access_ptr) :
               vector_base_ ;
         }

         vector_holder_ptr vector_holder_;
         T*                vector_base_;
         branch_t          vector_node_;
         branch_t          index_;
         vector_access_runtime_check_ptr vec_rt_chk_;
         const std::size_t max_vector_index_;
      };

      template <typename T>
      class vector_celem_rtc_node exprtk_final
                                 : public expression_node<T>
                                 , public ivariable      <T>
      {
      public:

         typedef expression_node<T>*            expression_ptr;
         typedef vector_holder<T>               vector_holder_t;
         typedef vector_holder_t*               vector_holder_ptr;
         typedef std::pair<expression_ptr,bool> branch_t;

         vector_celem_rtc_node(expression_ptr vec_node,
                               const std::size_t index,
                               vector_holder_ptr vec_holder,
                               vector_access_runtime_check_ptr vec_rt_chk)
         : index_(index)
         , max_vector_index_(vec_holder->size() - 1)
         , vector_holder_(vec_holder)
         , vector_base_((*vec_holder)[0])
         , vec_rt_chk_(vec_rt_chk)
         {
            construct_branch_pair(vector_node_, vec_node);
            assert(valid());
         }

         inline T value() const exprtk_override
         {
            return *access_vector();
         }

         inline T& ref() exprtk_override
         {
            return *access_vector();
         }

         inline const T& ref() const exprtk_override
         {
            return *access_vector();
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_veccelemrtc;
         }

         inline bool valid() const exprtk_override
         {
            return
               vector_holder_     &&
               vector_node_.first &&
               vector_node_.first->valid();
         }

         inline vector_holder_t& vec_holder()
         {
            return (*vector_holder_);
         }

         void collect_nodes(typename expression_node<T>::noderef_list_t& node_delete_list) exprtk_override
         {
            expression_node<T>::ndb_t::collect(vector_node_, node_delete_list);
         }

         std::size_t node_depth() const exprtk_override
         {
            return expression_node<T>::ndb_t::compute_node_depth(vector_node_);
         }

      private:

         inline T* access_vector() const
         {
            vector_node_.first->value();

            if (index_ <= max_vector_index_)
            {
               return (vector_holder_->data() + index_);
            }

            assert(vec_rt_chk_);

            vector_access_runtime_check::violation_context context;
            context.base_ptr   = reinterpret_cast<void*>(vector_base_);
            context.end_ptr    = reinterpret_cast<void*>(vector_base_ + vector_holder_->size());
            context.access_ptr = reinterpret_cast<void*>(vector_base_ + index_);
            context.type_size  = sizeof(T);

            return vec_rt_chk_->handle_runtime_violation(context) ?
               reinterpret_cast<T*>(context.access_ptr) :
               vector_base_ ;
         }

         const std::size_t index_;
         const std::size_t max_vector_index_;
         vector_holder_ptr vector_holder_;
         T*                vector_base_;
         branch_t          vector_node_;
         vector_access_runtime_check_ptr vec_rt_chk_;
      };

      template <typename T>
      class rebasevector_elem_node exprtk_final
                                   : public expression_node<T>
                                   , public ivariable      <T>
      {
      public:

         typedef expression_node<T>*            expression_ptr;
         typedef vector_holder<T>               vector_holder_t;
         typedef vector_holder_t*               vector_holder_ptr;
         typedef vec_data_store<T>              vds_t;
         typedef std::pair<expression_ptr,bool> branch_t;

         rebasevector_elem_node(expression_ptr vec_node,
                                expression_ptr index,
                                vector_holder_ptr vec_holder)
         : vector_holder_(vec_holder)
         {
            construct_branch_pair(vector_node_, vec_node);
            construct_branch_pair(index_      , index   );
            assert(valid());
         }

         inline T value() const exprtk_override
         {
            return *access_vector();
         }

         inline T& ref() exprtk_override
         {
            return *access_vector();
         }

         inline const T& ref() const exprtk_override
         {
            return *access_vector();
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_rbvecelem;
         }

         inline bool valid() const exprtk_override
         {
            return
               vector_holder_        &&
               index_.first          &&
               vector_node_.first    &&
               index_.first->valid() &&
               vector_node_.first->valid();
         }

         inline vector_holder_t& vec_holder()
         {
            return (*vector_holder_);
         }

         void collect_nodes(typename expression_node<T>::noderef_list_t& node_delete_list) exprtk_override
         {
            expression_node<T>::ndb_t::collect(vector_node_, node_delete_list);
            expression_node<T>::ndb_t::collect(index_,       node_delete_list);
         }

         std::size_t node_depth() const exprtk_override
         {
            return expression_node<T>::ndb_t::compute_node_depth
               (vector_node_, index_);
         }

      private:

         inline T* access_vector() const
         {
            vector_node_.first->value();
            return (vector_holder_->data() + details::numeric::to_uint64(index_.first->value()));
         }

         vector_holder_ptr vector_holder_;
         branch_t          vector_node_;
         branch_t          index_;
      };

      template <typename T>
      class rebasevector_celem_node exprtk_final
                                    : public expression_node<T>
                                    , public ivariable      <T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         typedef vector_holder<T>    vector_holder_t;
         typedef vector_holder_t*    vector_holder_ptr;
         typedef std::pair<expression_ptr,bool> branch_t;

         rebasevector_celem_node(expression_ptr vec_node,
                                 const std::size_t index,
                                 vector_holder_ptr vec_holder)
         : index_(index)
         , vector_holder_(vec_holder)
         {
            construct_branch_pair(vector_node_, vec_node);
            assert(valid());
         }

         inline T value() const exprtk_override
         {
            vector_node_.first->value();
            return ref();
         }

         inline T& ref() exprtk_override
         {
            return *(vector_holder_->data() + index_);
         }

         inline const T& ref() const exprtk_override
         {
            return *(vector_holder_->data() + index_);
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_rbveccelem;
         }

         inline bool valid() const exprtk_override
         {
            return
               vector_holder_     &&
               vector_node_.first &&
               vector_node_.first->valid();
         }

         inline vector_holder_t& vec_holder()
         {
            return (*vector_holder_);
         }

         void collect_nodes(typename expression_node<T>::noderef_list_t& node_delete_list) exprtk_override
         {
            expression_node<T>::ndb_t::collect(vector_node_, node_delete_list);
         }

         std::size_t node_depth() const exprtk_override
         {
            return expression_node<T>::ndb_t::compute_node_depth(vector_node_);
         }

      private:

         const std::size_t index_;
         vector_holder_ptr vector_holder_;
         branch_t          vector_node_;
      };

      template <typename T>
      class rebasevector_elem_rtc_node exprtk_final
                                       : public expression_node<T>
                                       , public ivariable      <T>
      {
      public:

         typedef expression_node<T>*            expression_ptr;
         typedef vector_holder<T>               vector_holder_t;
         typedef vector_holder_t*               vector_holder_ptr;
         typedef std::pair<expression_ptr,bool> branch_t;

         rebasevector_elem_rtc_node(expression_ptr vec_node,
                                    expression_ptr index,
                                    vector_holder_ptr vec_holder,
                                    vector_access_runtime_check_ptr vec_rt_chk)
         : vector_holder_(vec_holder)
         , vec_rt_chk_(vec_rt_chk)
         {
            construct_branch_pair(vector_node_, vec_node);
            construct_branch_pair(index_      , index   );
            assert(valid());
         }

         inline T value() const exprtk_override
         {
            return *access_vector();
         }

         inline T& ref() exprtk_override
         {
            return *access_vector();
         }

         inline const T& ref() const exprtk_override
         {
            return *access_vector();
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_rbvecelemrtc;
         }

         inline bool valid() const exprtk_override
         {
            return
               vector_holder_        &&
               index_.first          &&
               vector_node_.first    &&
               index_.first->valid() &&
               vector_node_.first->valid();
         }

         inline vector_holder_t& vec_holder()
         {
            return (*vector_holder_);
         }

         void collect_nodes(typename expression_node<T>::noderef_list_t& node_delete_list) exprtk_override
         {
            expression_node<T>::ndb_t::collect(vector_node_, node_delete_list);
            expression_node<T>::ndb_t::collect(index_      , node_delete_list);
         }

         std::size_t node_depth() const exprtk_override
         {
            return expression_node<T>::ndb_t::compute_node_depth
               (vector_node_, index_);
         }

      private:

         inline T* access_vector() const
         {
            vector_node_.first->value();
            const _uint64_t index = details::numeric::to_uint64(index_.first->value());

            if (index <= (vector_holder_->size() - 1))
            {
               return (vector_holder_->data() + index);
            }

            assert(vec_rt_chk_);

            vector_access_runtime_check::violation_context context;
            context.base_ptr   = reinterpret_cast<void*>(vector_holder_->data());
            context.end_ptr    = reinterpret_cast<void*>(vector_holder_->data() + vector_holder_->size());
            context.access_ptr = reinterpret_cast<void*>(vector_holder_->data() + index);
            context.type_size  = sizeof(T);

            return vec_rt_chk_->handle_runtime_violation(context) ?
                   reinterpret_cast<T*>(context.access_ptr) :
                   vector_holder_->data() ;
         }

         vector_holder_ptr vector_holder_;
         branch_t          vector_node_;
         branch_t          index_;
         vector_access_runtime_check_ptr vec_rt_chk_;
      };

      template <typename T>
      class rebasevector_celem_rtc_node exprtk_final
                                    : public expression_node<T>
                                    , public ivariable      <T>
      {
      public:

         typedef expression_node<T>*            expression_ptr;
         typedef vector_holder<T>               vector_holder_t;
         typedef vector_holder_t*               vector_holder_ptr;
         typedef std::pair<expression_ptr,bool> branch_t;

         rebasevector_celem_rtc_node(expression_ptr vec_node,
                                     const std::size_t index,
                                     vector_holder_ptr vec_holder,
                                     vector_access_runtime_check_ptr vec_rt_chk)
         : index_(index)
         , vector_holder_(vec_holder)
         , vector_base_((*vec_holder)[0])
         , vec_rt_chk_(vec_rt_chk)
         {
            construct_branch_pair(vector_node_, vec_node);
            assert(valid());
         }

         inline T value() const exprtk_override
         {
            return *access_vector();
         }

         inline T& ref() exprtk_override
         {
            return *access_vector();
         }

         inline const T& ref() const exprtk_override
         {
            return *access_vector();
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_rbveccelemrtc;
         }

         inline bool valid() const exprtk_override
         {
            return
               vector_holder_     &&
               vector_node_.first &&
               vector_node_.first->valid();
         }

         inline vector_holder_t& vec_holder()
         {
            return (*vector_holder_);
         }

         void collect_nodes(typename expression_node<T>::noderef_list_t& node_delete_list) exprtk_override
         {
            expression_node<T>::ndb_t::collect(vector_node_, node_delete_list);
         }

         std::size_t node_depth() const exprtk_override
         {
            return expression_node<T>::ndb_t::compute_node_depth(vector_node_);
         }

      private:

         inline T* access_vector() const
         {
            vector_node_.first->value();

            if (index_ <= vector_holder_->size() - 1)
            {
               return (vector_holder_->data() + index_);
            }

            assert(vec_rt_chk_);

            vector_access_runtime_check::violation_context context;
            context.base_ptr   = reinterpret_cast<void*>(vector_base_);
            context.end_ptr    = reinterpret_cast<void*>(vector_base_ + vector_holder_->size());
            context.access_ptr = reinterpret_cast<void*>(vector_base_ + index_);
            context.type_size  = sizeof(T);

            return vec_rt_chk_->handle_runtime_violation(context) ?
               reinterpret_cast<T*>(context.access_ptr) :
               vector_base_ ;
         }

         const std::size_t index_;
         vector_holder_ptr vector_holder_;
         T*                vector_base_;
         branch_t          vector_node_;
         vector_access_runtime_check_ptr vec_rt_chk_;
      };

      template <typename T>
      class vector_initialisation_node exprtk_final : public expression_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;

         vector_initialisation_node(T* vector_base,
                                    const std::size_t& size,
                                    const std::vector<expression_ptr>& initialiser_list,
                                    const bool single_value_initialse)
         : vector_base_(vector_base)
         , initialiser_list_(initialiser_list)
         , size_(size)
         , single_value_initialse_(single_value_initialse)
         , zero_value_initialse_(false)
         , const_nonzero_literal_value_initialse_(false)
         , single_initialiser_value_(T(0))
         {
            if (single_value_initialse_)
            {
               if (initialiser_list_.empty())
                  zero_value_initialse_ = true;
               else if (
                         (initialiser_list_.size() == 1) &&
                         details::is_constant_node(initialiser_list_[0]) &&
                         (T(0) == initialiser_list_[0]->value())
                       )
               {
                  zero_value_initialse_ = true;
               }
               else
               {
                  assert(initialiser_list_.size() == 1);

                  if (details::is_constant_node(initialiser_list_[0]))
                  {
                     const_nonzero_literal_value_initialse_ = true;
                     single_initialiser_value_ = initialiser_list_[0]->value();
                     assert(T(0) != single_initialiser_value_);
                  }
               }
            }
         }

         inline T value() const exprtk_override
         {
            if (single_value_initialse_)
            {
               if (zero_value_initialse_)
               {
                  details::set_zero_value(vector_base_, size_);
               }
               else if (const_nonzero_literal_value_initialse_)
               {
                  for (std::size_t i = 0; i < size_; ++i)
                  {
                     *(vector_base_ + i) = single_initialiser_value_;
                  }
               }
               else
               {
                  for (std::size_t i = 0; i < size_; ++i)
                  {
                     *(vector_base_ + i) = initialiser_list_[0]->value();
                  }
               }
            }
            else
            {
               const std::size_t initialiser_list_size = initialiser_list_.size();

               for (std::size_t i = 0; i < initialiser_list_size; ++i)
               {
                  *(vector_base_ + i) = initialiser_list_[i]->value();
               }

               if (initialiser_list_size < size_)
               {
                  details::set_zero_value(
                     vector_base_ + initialiser_list_size,
                     (size_ - initialiser_list_size));
               }
            }

            return *(vector_base_);
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_vecinit;
         }

         inline bool valid() const exprtk_override
         {
            return vector_base_;
         }

         void collect_nodes(typename expression_node<T>::noderef_list_t& node_delete_list) exprtk_override
         {
            expression_node<T>::ndb_t::collect(initialiser_list_, node_delete_list);
         }

         std::size_t node_depth() const exprtk_override
         {
            return expression_node<T>::ndb_t::compute_node_depth(initialiser_list_);
         }

      private:

         vector_initialisation_node(const vector_initialisation_node<T>&) exprtk_delete;
         vector_initialisation_node<T>& operator=(const vector_initialisation_node<T>&) exprtk_delete;

         mutable T* vector_base_;
         std::vector<expression_ptr> initialiser_list_;
         const std::size_t size_;
         const bool single_value_initialse_;
         bool zero_value_initialse_;
         bool const_nonzero_literal_value_initialse_;
         T single_initialiser_value_;
      };

      template <typename T>
      class vector_init_zero_value_node exprtk_final : public expression_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;

         vector_init_zero_value_node(T* vector_base,
                                     const std::size_t& size,
                                     const std::vector<expression_ptr>& initialiser_list)
         : vector_base_(vector_base)
         , size_(size)
         , initialiser_list_(initialiser_list)
         {}

         inline T value() const exprtk_override
         {
            details::set_zero_value(vector_base_, size_);
            return *(vector_base_);
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_vecinit;
         }

         inline bool valid() const exprtk_override
         {
            return vector_base_;
         }

         void collect_nodes(typename expression_node<T>::noderef_list_t& node_delete_list) exprtk_override
         {
            expression_node<T>::ndb_t::collect(initialiser_list_, node_delete_list);
         }

         std::size_t node_depth() const exprtk_override
         {
            return expression_node<T>::ndb_t::compute_node_depth(initialiser_list_);
         }

      private:

         vector_init_zero_value_node(const vector_init_zero_value_node<T>&) exprtk_delete;
         vector_init_zero_value_node<T>& operator=(const vector_init_zero_value_node<T>&) exprtk_delete;

         mutable T* vector_base_;
         const std::size_t size_;
         std::vector<expression_ptr> initialiser_list_;
      };

      template <typename T>
      class vector_init_single_constvalue_node exprtk_final : public expression_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;

         vector_init_single_constvalue_node(T* vector_base,
                                            const std::size_t& size,
                                            const std::vector<expression_ptr>& initialiser_list)
         : vector_base_(vector_base)
         , size_(size)
         , initialiser_list_(initialiser_list)
         {
            single_initialiser_value_ = initialiser_list_[0]->value();
            assert(valid());
         }

         inline T value() const exprtk_override
         {
            for (std::size_t i = 0; i < size_; ++i)
            {
               *(vector_base_ + i) = single_initialiser_value_;
            }

            return *(vector_base_);
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_vecinit;
         }

         inline bool valid() const exprtk_override
         {
            return vector_base_ &&
                   (initialiser_list_.size() == 1) &&
                   (details::is_constant_node(initialiser_list_[0])) &&
                   (single_initialiser_value_ != T(0));
         }

         void collect_nodes(typename expression_node<T>::noderef_list_t& node_delete_list) exprtk_override
         {
            expression_node<T>::ndb_t::collect(initialiser_list_, node_delete_list);
         }

         std::size_t node_depth() const exprtk_override
         {
            return expression_node<T>::ndb_t::compute_node_depth(initialiser_list_);
         }

      private:

         vector_init_single_constvalue_node(const vector_init_single_constvalue_node<T>&) exprtk_delete;
         vector_init_single_constvalue_node<T>& operator=(const vector_init_single_constvalue_node<T>&) exprtk_delete;

         mutable T* vector_base_;
         const std::size_t size_;
         std::vector<expression_ptr> initialiser_list_;
         T single_initialiser_value_;
      };

      template <typename T>
      class vector_init_single_value_node exprtk_final : public expression_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;

         vector_init_single_value_node(T* vector_base,
                                       const std::size_t& size,
                                       const std::vector<expression_ptr>& initialiser_list)
         : vector_base_(vector_base)
         , size_(size)
         , initialiser_list_(initialiser_list)
         {
            assert(valid());
         }

         inline T value() const exprtk_override
         {
            expression_node<T>& node = *initialiser_list_[0];

            for (std::size_t i = 0; i < size_; ++i)
            {
               *(vector_base_ + i) = node.value();
            }

            return *(vector_base_);
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_vecinit;
         }

         inline bool valid() const exprtk_override
         {
            return vector_base_ &&
                   (initialiser_list_.size() == 1) &&
                   !details::is_constant_node(initialiser_list_[0]);
         }

         void collect_nodes(typename expression_node<T>::noderef_list_t& node_delete_list) exprtk_override
         {
            expression_node<T>::ndb_t::collect(initialiser_list_, node_delete_list);
         }

         std::size_t node_depth() const exprtk_override
         {
            return expression_node<T>::ndb_t::compute_node_depth(initialiser_list_);
         }

      private:

         vector_init_single_value_node(const vector_init_single_value_node<T>&) exprtk_delete;
         vector_init_single_value_node<T>& operator=(const vector_init_single_value_node<T>&) exprtk_delete;

         mutable T* vector_base_;
         const std::size_t size_;
         std::vector<expression_ptr> initialiser_list_;
      };

      template <typename T>
      class vector_init_iota_constconst_node exprtk_final : public expression_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;

         vector_init_iota_constconst_node(T* vector_base,
                                          const std::size_t& size,
                                          const std::vector<expression_ptr>& initialiser_list)
         : vector_base_(vector_base)
         , size_(size)
         , initialiser_list_(initialiser_list)
         {
            base_value_      = initialiser_list_[0]->value();
            increment_value_ = initialiser_list_[1]->value();

            assert(valid());
         }

         inline T value() const exprtk_override
         {
            T value = base_value_;

            for (std::size_t i = 0; i < size_; ++i, value += increment_value_)
            {
               *(vector_base_ + i) = value;
            }

            return *(vector_base_);
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_vecinit;
         }

         inline bool valid() const exprtk_override
         {
            return vector_base_ &&
                   (initialiser_list_.size() == 2) &&
                   (details::is_constant_node(initialiser_list_[0])) &&
                   (details::is_constant_node(initialiser_list_[1])) ;
         }

         void collect_nodes(typename expression_node<T>::noderef_list_t& node_delete_list) exprtk_override
         {
            expression_node<T>::ndb_t::collect(initialiser_list_, node_delete_list);
         }

         std::size_t node_depth() const exprtk_override
         {
            return expression_node<T>::ndb_t::compute_node_depth(initialiser_list_);
         }

      private:

         vector_init_iota_constconst_node(const vector_init_iota_constconst_node<T>&) exprtk_delete;
         vector_init_iota_constconst_node<T>& operator=(const vector_init_iota_constconst_node<T>&) exprtk_delete;

         mutable T* vector_base_;
         const std::size_t size_;
         std::vector<expression_ptr> initialiser_list_;
         T base_value_;
         T increment_value_;
      };

      template <typename T>
      class vector_init_iota_constnconst_node exprtk_final : public expression_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;

         vector_init_iota_constnconst_node(T* vector_base,
                                           const std::size_t& size,
                                           const std::vector<expression_ptr>& initialiser_list)
         : vector_base_(vector_base)
         , size_(size)
         , initialiser_list_(initialiser_list)
         {
            assert(valid());
            base_value_ = initialiser_list_[0]->value();
         }

         inline T value() const exprtk_override
         {
            T value = base_value_;
            expression_node<T>& increment = *initialiser_list_[1];

            for (std::size_t i = 0; i < size_; ++i, value += increment.value())
            {
               *(vector_base_ + i) = value;
            }

            return *(vector_base_);
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_vecinit;
         }

         inline bool valid() const exprtk_override
         {
            return vector_base_ &&
                  (initialiser_list_.size() == 2) &&
                  ( details::is_constant_node(initialiser_list_[0])) &&
                  (!details::is_constant_node(initialiser_list_[1]));
         }

         void collect_nodes(typename expression_node<T>::noderef_list_t& node_delete_list) exprtk_override
         {
            expression_node<T>::ndb_t::collect(initialiser_list_, node_delete_list);
         }

         std::size_t node_depth() const exprtk_override
         {
            return expression_node<T>::ndb_t::compute_node_depth(initialiser_list_);
         }

      private:

         vector_init_iota_constnconst_node(const vector_init_iota_constnconst_node<T>&) exprtk_delete;
         vector_init_iota_constnconst_node<T>& operator=(const vector_init_iota_constnconst_node<T>&) exprtk_delete;

         mutable T* vector_base_;
         const std::size_t size_;
         std::vector<expression_ptr> initialiser_list_;
         T base_value_;
      };

      template <typename T>
      class vector_init_iota_nconstconst_node exprtk_final : public expression_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;

         vector_init_iota_nconstconst_node(T* vector_base,
                                           const std::size_t& size,
                                           const std::vector<expression_ptr>& initialiser_list)
         : vector_base_(vector_base)
         , size_(size)
         , initialiser_list_(initialiser_list)
         {
            assert(valid());
         }

         inline T value() const exprtk_override
         {
            T value = initialiser_list_[0]->value();
            const T increment = initialiser_list_[1]->value();

            for (std::size_t i = 0; i < size_; ++i, value += increment)
            {
               *(vector_base_ + i) = value;
            }

            return *(vector_base_);
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_vecinit;
         }

         inline bool valid() const exprtk_override
         {
            return vector_base_ &&
                   (initialiser_list_.size() == 2) &&
                   (!details::is_constant_node(initialiser_list_[0])) &&
                   (details::is_constant_node(initialiser_list_[1]));
         }

         void collect_nodes(typename expression_node<T>::noderef_list_t& node_delete_list) exprtk_override
         {
            expression_node<T>::ndb_t::collect(initialiser_list_, node_delete_list);
         }

         std::size_t node_depth() const exprtk_override
         {
            return expression_node<T>::ndb_t::compute_node_depth(initialiser_list_);
         }

      private:

         vector_init_iota_nconstconst_node(const vector_init_iota_nconstconst_node<T>&) exprtk_delete;
         vector_init_iota_nconstconst_node<T>& operator=(const vector_init_iota_nconstconst_node<T>&) exprtk_delete;

         mutable T* vector_base_;
         const std::size_t size_;
         std::vector<expression_ptr> initialiser_list_;
      };

      template <typename T>
      class vector_init_iota_nconstnconst_node exprtk_final : public expression_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;

         vector_init_iota_nconstnconst_node(T* vector_base,
                                            const std::size_t& size,
                                            const std::vector<expression_ptr>& initialiser_list)
         : vector_base_(vector_base)
         , size_(size)
         , initialiser_list_(initialiser_list)
         {
            assert(valid());
         }

         inline T value() const exprtk_override
         {
            T value = initialiser_list_[0]->value();
            expression_node<T>& increment = *initialiser_list_[1];

            for (std::size_t i = 0; i < size_; ++i, value += increment.value())
            {
               *(vector_base_ + i) = value;
            }

            return *(vector_base_);
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_vecinit;
         }

         inline bool valid() const exprtk_override
         {
            return vector_base_ &&
                   (initialiser_list_.size() == 2) &&
                   (!details::is_constant_node(initialiser_list_[0])) &&
                   (!details::is_constant_node(initialiser_list_[1]));
         }

         void collect_nodes(typename expression_node<T>::noderef_list_t& node_delete_list) exprtk_override
         {
            expression_node<T>::ndb_t::collect(initialiser_list_, node_delete_list);
         }

         std::size_t node_depth() const exprtk_override
         {
            return expression_node<T>::ndb_t::compute_node_depth(initialiser_list_);
         }

      private:

         vector_init_iota_nconstnconst_node(const vector_init_iota_nconstnconst_node<T>&) exprtk_delete;
         vector_init_iota_nconstnconst_node<T>& operator=(const vector_init_iota_nconstnconst_node<T>&) exprtk_delete;

         mutable T* vector_base_;
         const std::size_t size_;
         std::vector<expression_ptr> initialiser_list_;
      };

      template <typename T>
      class swap_node exprtk_final : public expression_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         typedef variable_node<T>*   variable_node_ptr;

         swap_node(variable_node_ptr var0, variable_node_ptr var1)
         : var0_(var0)
         , var1_(var1)
         {}

         inline T value() const exprtk_override
         {
            std::swap(var0_->ref(),var1_->ref());
            return var1_->ref();
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_swap;
         }

      private:

         variable_node_ptr var0_;
         variable_node_ptr var1_;
      };

      template <typename T>
      class swap_generic_node exprtk_final : public binary_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         typedef ivariable<T>*       ivariable_ptr;

         swap_generic_node(expression_ptr var0, expression_ptr var1)
         : binary_node<T>(details::e_swap, var0, var1)
         , var0_(dynamic_cast<ivariable_ptr>(var0))
         , var1_(dynamic_cast<ivariable_ptr>(var1))
         {}

         inline T value() const exprtk_override
         {
            std::swap(var0_->ref(),var1_->ref());
            return var1_->ref();
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_swap;
         }

      private:

         ivariable_ptr var0_;
         ivariable_ptr var1_;
      };

      template <typename T>
      class swap_vecvec_node exprtk_final
                             : public binary_node     <T>
                             , public vector_interface<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         typedef vector_node    <T>* vector_node_ptr;
         typedef vec_data_store <T>  vds_t;

         using binary_node<T>::branch;

         swap_vecvec_node(expression_ptr branch0,
                          expression_ptr branch1)
         : binary_node<T>(details::e_swap, branch0, branch1)
         , vec0_node_ptr_(0)
         , vec1_node_ptr_(0)
         , initialised_  (false)
         {
            if (is_ivector_node(branch(0)))
            {
               vector_interface<T>* vi = reinterpret_cast<vector_interface<T>*>(0);

               if (0 != (vi = dynamic_cast<vector_interface<T>*>(branch(0))))
               {
                  vec0_node_ptr_ = vi->vec();
                  vds()          = vi->vds();
               }
            }

            if (is_ivector_node(branch(1)))
            {
               vector_interface<T>* vi = reinterpret_cast<vector_interface<T>*>(0);

               if (0 != (vi = dynamic_cast<vector_interface<T>*>(branch(1))))
               {
                  vec1_node_ptr_ = vi->vec();
               }
            }

            if (vec0_node_ptr_ && vec1_node_ptr_)
            {
               initialised_ = size() <= base_size();
            }

            assert(valid());
         }

         inline T value() const exprtk_override
         {
            binary_node<T>::branch(0)->value();
            binary_node<T>::branch(1)->value();

            T* vec0 = vec0_node_ptr_->vds().data();
            T* vec1 = vec1_node_ptr_->vds().data();

            assert(size() <= base_size());
            const std::size_t n = size();

            for (std::size_t i = 0; i < n; ++i)
            {
               std::swap(vec0[i],vec1[i]);
            }

            return vec1_node_ptr_->value();
         }

         vector_node_ptr vec() const exprtk_override
         {
            return vec0_node_ptr_;
         }

         vector_node_ptr vec() exprtk_override
         {
            return vec0_node_ptr_;
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_vecvecswap;
         }

         inline bool valid() const exprtk_override
         {
            return initialised_ && binary_node<T>::valid();
         }

         std::size_t size() const exprtk_override
         {
            return std::min(
               vec0_node_ptr_->vec_holder().size(),
               vec1_node_ptr_->vec_holder().size());
         }

         std::size_t base_size() const exprtk_override
         {
            return std::min(
               vec0_node_ptr_->vec_holder().base_size(),
               vec1_node_ptr_->vec_holder().base_size());
         }

         vds_t& vds() exprtk_override
         {
            return vds_;
         }

         const vds_t& vds() const exprtk_override
         {
            return vds_;
         }

      private:

         vector_node<T>* vec0_node_ptr_;
         vector_node<T>* vec1_node_ptr_;
         bool            initialised_;
         vds_t           vds_;
      };

      #ifndef exprtk_disable_string_capabilities
      template <typename T>
      class stringvar_node exprtk_final
                           : public expression_node <T>
                           , public string_base_node<T>
                           , public range_interface <T>
      {
      public:

         typedef typename range_interface<T>::range_t range_t;

         static std::string null_value;

         explicit stringvar_node()
         : value_(&null_value)
         {}

         explicit stringvar_node(std::string& v)
         : value_(&v)
         {
            rp_.n0_c = std::make_pair<bool,std::size_t>(true,0);
            rp_.n1_c = std::make_pair<bool,std::size_t>(true,v.size());
            rp_.cache.first  = rp_.n0_c.second;
            rp_.cache.second = rp_.n1_c.second;
         }

         inline bool operator <(const stringvar_node<T>& v) const
         {
            return this < (&v);
         }

         inline T value() const exprtk_override
         {
            rp_.n1_c.second  = (*value_).size();
            rp_.cache.second = rp_.n1_c.second;

            return std::numeric_limits<T>::quiet_NaN();
         }

         std::string str() const exprtk_override
         {
            return ref();
         }

         char_cptr base() const exprtk_override
         {
            return &(*value_)[0];
         }

         std::size_t size() const exprtk_override
         {
            return ref().size();
         }

         std::string& ref()
         {
            return (*value_);
         }

         const std::string& ref() const
         {
            return (*value_);
         }

         range_t& range_ref() exprtk_override
         {
            return rp_;
         }

         const range_t& range_ref() const exprtk_override
         {
            return rp_;
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_stringvar;
         }

         void rebase(std::string& s)
         {
            value_ = &s;
            rp_.n0_c = std::make_pair<bool,std::size_t>(true,0);
            rp_.n1_c = std::make_pair<bool,std::size_t>(true,value_->size() - 1);
            rp_.cache.first  = rp_.n0_c.second;
            rp_.cache.second = rp_.n1_c.second;
         }

      private:

         std::string* value_;
         mutable range_t rp_;
      };

      template <typename T>
      std::string stringvar_node<T>::null_value = std::string("");

      template <typename T>
      class string_range_node exprtk_final
                              : public expression_node <T>
                              , public string_base_node<T>
                              , public range_interface <T>
      {
      public:

         typedef typename range_interface<T>::range_t range_t;

         static std::string null_value;

         explicit string_range_node(std::string& v, const range_t& rp)
         : value_(&v)
         , rp_(rp)
         {}

         virtual ~string_range_node()
         {
            rp_.free();
         }

         inline bool operator <(const string_range_node<T>& v) const
         {
            return this < (&v);
         }

         inline T value() const exprtk_override
         {
            return std::numeric_limits<T>::quiet_NaN();
         }

         inline std::string str() const exprtk_override
         {
            return (*value_);
         }

         char_cptr base() const exprtk_override
         {
            return &(*value_)[0];
         }

         std::size_t size() const exprtk_override
         {
            return ref().size();
         }

         inline range_t range() const
         {
            return rp_;
         }

         inline virtual std::string& ref()
         {
            return (*value_);
         }

         inline virtual const std::string& ref() const
         {
            return (*value_);
         }

         inline range_t& range_ref() exprtk_override
         {
            return rp_;
         }

         inline const range_t& range_ref() const exprtk_override
         {
            return rp_;
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_stringvarrng;
         }

      private:

         std::string* value_;
         range_t      rp_;
      };

      template <typename T>
      std::string string_range_node<T>::null_value = std::string("");

      template <typename T>
      class const_string_range_node exprtk_final
                                    : public expression_node <T>
                                    , public string_base_node<T>
                                    , public range_interface <T>
      {
      public:

         typedef typename range_interface<T>::range_t range_t;

         explicit const_string_range_node(const std::string& v, const range_t& rp)
         : value_(v)
         , rp_(rp)
         {}

        ~const_string_range_node() exprtk_override
         {
            rp_.free();
         }

         inline T value() const exprtk_override
         {
            return std::numeric_limits<T>::quiet_NaN();
         }

         std::string str() const exprtk_override
         {
            return value_;
         }

         char_cptr base() const exprtk_override
         {
            return value_.data();
         }

         std::size_t size() const exprtk_override
         {
            return value_.size();
         }

         range_t range() const
         {
            return rp_;
         }

         range_t& range_ref() exprtk_override
         {
            return rp_;
         }

         const range_t& range_ref() const exprtk_override
         {
            return rp_;
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_cstringvarrng;
         }

      private:

         const_string_range_node(const const_string_range_node<T>&) exprtk_delete;
         const_string_range_node<T>& operator=(const const_string_range_node<T>&) exprtk_delete;

         const std::string value_;
         range_t rp_;
      };

      template <typename T>
      class generic_string_range_node exprtk_final
                                      : public expression_node <T>
                                      , public string_base_node<T>
                                      , public range_interface <T>
      {
      public:

         typedef expression_node <T>* expression_ptr;
         typedef stringvar_node  <T>* strvar_node_ptr;
         typedef string_base_node<T>* str_base_ptr;
         typedef typename range_interface<T>::range_t range_t;
         typedef range_t*             range_ptr;
         typedef range_interface<T>   irange_t;
         typedef irange_t*            irange_ptr;
         typedef std::pair<expression_ptr,bool>  branch_t;

         generic_string_range_node(expression_ptr str_branch, const range_t& brange)
         : initialised_(false)
         , str_base_ptr_ (0)
         , str_range_ptr_(0)
         , base_range_(brange)
         {
            range_.n0_c = std::make_pair<bool,std::size_t>(true,0);
            range_.n1_c = std::make_pair<bool,std::size_t>(true,0);
            range_.cache.first  = range_.n0_c.second;
            range_.cache.second = range_.n1_c.second;

            construct_branch_pair(branch_, str_branch);

            if (is_generally_string_node(branch_.first))
            {
               str_base_ptr_ = dynamic_cast<str_base_ptr>(branch_.first);

               if (0 == str_base_ptr_)
                  return;

               str_range_ptr_ = dynamic_cast<irange_ptr>(branch_.first);

               if (0 == str_range_ptr_)
                  return;
            }

            initialised_ = (str_base_ptr_ && str_range_ptr_);
            assert(valid());
         }

        ~generic_string_range_node() exprtk_override
         {
            base_range_.free();
         }

         inline T value() const exprtk_override
         {
            branch_.first->value();

            std::size_t str_r0 = 0;
            std::size_t str_r1 = 0;

            std::size_t r0 = 0;
            std::size_t r1 = 0;

            const range_t& range = str_range_ptr_->range_ref();

            const std::size_t base_str_size = str_base_ptr_->size();

            if (
                  range      (str_r0, str_r1, base_str_size         ) &&
                  base_range_(r0    , r1    , base_str_size - str_r0)
               )
            {
               const std::size_t size = r1 - r0;

               range_.n1_c.second  = size;
               range_.cache.second = range_.n1_c.second;

               value_.assign(str_base_ptr_->base() + str_r0 + r0, size);
            }

            return std::numeric_limits<T>::quiet_NaN();
         }

         std::string str() const exprtk_override
         {
            return value_;
         }

         char_cptr base() const exprtk_override
         {
            return &value_[0];
         }

         std::size_t size() const exprtk_override
         {
            return value_.size();
         }

         range_t& range_ref() exprtk_override
         {
            return range_;
         }

         const range_t& range_ref() const exprtk_override
         {
            return range_;
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_strgenrange;
         }

         inline bool valid() const exprtk_override
         {
            return initialised_ && branch_.first;
         }

         void collect_nodes(typename expression_node<T>::noderef_list_t& node_delete_list) exprtk_override
         {
            expression_node<T>::ndb_t::collect(branch_, node_delete_list);
         }

         std::size_t node_depth() const exprtk_override
         {
            return expression_node<T>::ndb_t::compute_node_depth(branch_);
         }

      private:

         bool                initialised_;
         branch_t            branch_;
         str_base_ptr        str_base_ptr_;
         irange_ptr          str_range_ptr_;
         mutable range_t     base_range_;
         mutable range_t     range_;
         mutable std::string value_;
      };

      template <typename T>
      class string_concat_node exprtk_final
                               : public binary_node     <T>
                               , public string_base_node<T>
                               , public range_interface <T>
      {
      public:

         typedef typename range_interface<T>::range_t range_t;
         typedef range_interface<T>   irange_t;
         typedef irange_t*            irange_ptr;
         typedef range_t*             range_ptr;
         typedef expression_node <T>* expression_ptr;
         typedef string_base_node<T>* str_base_ptr;

         using binary_node<T>::branch;

         string_concat_node(const operator_type& opr,
                            expression_ptr branch0,
                            expression_ptr branch1)
         : binary_node<T>(opr, branch0, branch1)
         , initialised_(false)
         , str0_base_ptr_ (0)
         , str1_base_ptr_ (0)
         , str0_range_ptr_(0)
         , str1_range_ptr_(0)
         {
            range_.n0_c = std::make_pair<bool,std::size_t>(true,0);
            range_.n1_c = std::make_pair<bool,std::size_t>(true,0);

            range_.cache.first  = range_.n0_c.second;
            range_.cache.second = range_.n1_c.second;

            if (is_generally_string_node(branch(0)))
            {
               str0_base_ptr_ = dynamic_cast<str_base_ptr>(branch(0));

               if (0 == str0_base_ptr_)
                  return;

               str0_range_ptr_ = dynamic_cast<irange_ptr>(branch(0));

               if (0 == str0_range_ptr_)
                  return;
            }

            if (is_generally_string_node(branch(1)))
            {
               str1_base_ptr_ = dynamic_cast<str_base_ptr>(branch(1));

               if (0 == str1_base_ptr_)
                  return;

               str1_range_ptr_ = dynamic_cast<irange_ptr>(branch(1));

               if (0 == str1_range_ptr_)
                  return;
            }

            initialised_ = str0_base_ptr_  &&
                           str1_base_ptr_  &&
                           str0_range_ptr_ &&
                           str1_range_ptr_ ;

            assert(valid());
         }

         inline T value() const exprtk_override
         {
            branch(0)->value();
            branch(1)->value();

            std::size_t str0_r0 = 0;
            std::size_t str0_r1 = 0;

            std::size_t str1_r0 = 0;
            std::size_t str1_r1 = 0;

            const range_t& range0 = str0_range_ptr_->range_ref();
            const range_t& range1 = str1_range_ptr_->range_ref();

            if (
                  range0(str0_r0, str0_r1, str0_base_ptr_->size()) &&
                  range1(str1_r0, str1_r1, str1_base_ptr_->size())
               )
            {
               const std::size_t size0 = (str0_r1 - str0_r0);
               const std::size_t size1 = (str1_r1 - str1_r0);

               value_.assign(str0_base_ptr_->base() + str0_r0, size0);
               value_.append(str1_base_ptr_->base() + str1_r0, size1);

               range_.n1_c.second  = value_.size();
               range_.cache.second = range_.n1_c.second;
            }

            return std::numeric_limits<T>::quiet_NaN();
         }

         std::string str() const exprtk_override
         {
            return value_;
         }

         char_cptr base() const exprtk_override
         {
            return &value_[0];
         }

         std::size_t size() const exprtk_override
         {
            return value_.size();
         }

         range_t& range_ref() exprtk_override
         {
            return range_;
         }

         const range_t& range_ref() const exprtk_override
         {
            return range_;
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_strconcat;
         }

         inline bool valid() const exprtk_override
         {
            return initialised_ && binary_node<T>::valid();
         }

      private:

         bool                initialised_;
         str_base_ptr        str0_base_ptr_;
         str_base_ptr        str1_base_ptr_;
         irange_ptr          str0_range_ptr_;
         irange_ptr          str1_range_ptr_;
         mutable range_t     range_;
         mutable std::string value_;
      };

      template <typename T>
      class swap_string_node exprtk_final
                             : public binary_node     <T>
                             , public string_base_node<T>
                             , public range_interface <T>
      {
      public:

         typedef typename range_interface<T>::range_t range_t;
         typedef range_t*             range_ptr;
         typedef range_interface<T>   irange_t;
         typedef irange_t*            irange_ptr;
         typedef expression_node <T>* expression_ptr;
         typedef stringvar_node  <T>* strvar_node_ptr;
         typedef string_base_node<T>* str_base_ptr;

         using binary_node<T>::branch;

         swap_string_node(expression_ptr branch0, expression_ptr branch1)
         : binary_node<T>(details::e_swap, branch0, branch1)
         , initialised_(false)
         , str0_node_ptr_(0)
         , str1_node_ptr_(0)
         {
            if (is_string_node(branch(0)))
            {
               str0_node_ptr_ = static_cast<strvar_node_ptr>(branch(0));
            }

            if (is_string_node(branch(1)))
            {
               str1_node_ptr_ = static_cast<strvar_node_ptr>(branch(1));
            }

            initialised_ = (str0_node_ptr_ && str1_node_ptr_);
            assert(valid());
         }

         inline T value() const exprtk_override
         {
            branch(0)->value();
            branch(1)->value();

            std::swap(str0_node_ptr_->ref(), str1_node_ptr_->ref());

            return std::numeric_limits<T>::quiet_NaN();
         }

         std::string str() const exprtk_override
         {
            return str0_node_ptr_->str();
         }

         char_cptr base() const exprtk_override
         {
           return str0_node_ptr_->base();
         }

         std::size_t size() const exprtk_override
         {
            return str0_node_ptr_->size();
         }

         range_t& range_ref() exprtk_override
         {
            return str0_node_ptr_->range_ref();
         }

         const range_t& range_ref() const exprtk_override
         {
            return str0_node_ptr_->range_ref();
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_strswap;
         }

         inline bool valid() const exprtk_override
         {
            return initialised_ && binary_node<T>::valid();
         }

      private:

         bool initialised_;
         strvar_node_ptr str0_node_ptr_;
         strvar_node_ptr str1_node_ptr_;
      };

      template <typename T>
      class swap_genstrings_node exprtk_final : public binary_node<T>
      {
      public:

         typedef typename range_interface<T>::range_t range_t;
         typedef range_t*             range_ptr;
         typedef range_interface<T>   irange_t;
         typedef irange_t*            irange_ptr;
         typedef expression_node <T>* expression_ptr;
         typedef string_base_node<T>* str_base_ptr;

         using binary_node<T>::branch;

         swap_genstrings_node(expression_ptr branch0,
                              expression_ptr branch1)
         : binary_node<T>(details::e_default, branch0, branch1)
         , str0_base_ptr_ (0)
         , str1_base_ptr_ (0)
         , str0_range_ptr_(0)
         , str1_range_ptr_(0)
         , initialised_(false)
         {
            if (is_generally_string_node(branch(0)))
            {
               str0_base_ptr_ = dynamic_cast<str_base_ptr>(branch(0));

               if (0 == str0_base_ptr_)
                  return;

               irange_ptr range = dynamic_cast<irange_ptr>(branch(0));

               if (0 == range)
                  return;

               str0_range_ptr_ = &(range->range_ref());
            }

            if (is_generally_string_node(branch(1)))
            {
               str1_base_ptr_ = dynamic_cast<str_base_ptr>(branch(1));

               if (0 == str1_base_ptr_)
                  return;

               irange_ptr range = dynamic_cast<irange_ptr>(branch(1));

               if (0 == range)
                  return;

               str1_range_ptr_ = &(range->range_ref());
            }

            initialised_ = str0_base_ptr_  &&
                           str1_base_ptr_  &&
                           str0_range_ptr_ &&
                           str1_range_ptr_ ;

            assert(valid());
         }

         inline T value() const exprtk_override
         {
            branch(0)->value();
            branch(1)->value();

            std::size_t str0_r0 = 0;
            std::size_t str0_r1 = 0;

            std::size_t str1_r0 = 0;
            std::size_t str1_r1 = 0;

            const range_t& range0 = (*str0_range_ptr_);
            const range_t& range1 = (*str1_range_ptr_);

            if (
                  range0(str0_r0, str0_r1, str0_base_ptr_->size()) &&
                  range1(str1_r0, str1_r1, str1_base_ptr_->size())
               )
            {
               const std::size_t size0    = range0.cache_size();
               const std::size_t size1    = range1.cache_size();
               const std::size_t max_size = std::min(size0,size1);

               char_ptr s0 = const_cast<char_ptr>(str0_base_ptr_->base() + str0_r0);
               char_ptr s1 = const_cast<char_ptr>(str1_base_ptr_->base() + str1_r0);

               loop_unroll::details lud(max_size);
               char_cptr upper_bound = s0 + lud.upper_bound;

               while (s0 < upper_bound)
               {
                  #define exprtk_loop(N)   \
                  std::swap(s0[N], s1[N]); \

                  exprtk_loop( 0) exprtk_loop( 1)
                  exprtk_loop( 2) exprtk_loop( 3)
                  #ifndef exprtk_disable_superscalar_unroll
                  exprtk_loop( 4) exprtk_loop( 5)
                  exprtk_loop( 6) exprtk_loop( 7)
                  exprtk_loop( 8) exprtk_loop( 9)
                  exprtk_loop(10) exprtk_loop(11)
                  exprtk_loop(12) exprtk_loop(13)
                  exprtk_loop(14) exprtk_loop(15)
                  #endif

                  s0 += lud.batch_size;
                  s1 += lud.batch_size;
               }

               int i = 0;

               switch (lud.remainder)
               {
                  #define case_stmt(N)                       \
                  case N : { std::swap(s0[i], s1[i]); ++i; } \
                  exprtk_fallthrough                         \

                  #ifndef exprtk_disable_superscalar_unroll
                  case_stmt(15) case_stmt(14)
                  case_stmt(13) case_stmt(12)
                  case_stmt(11) case_stmt(10)
                  case_stmt( 9) case_stmt( 8)
                  case_stmt( 7) case_stmt( 6)
                  case_stmt( 5) case_stmt( 4)
                  #endif
                  case_stmt( 3) case_stmt( 2)
                  case_stmt( 1)
                  default: break;
               }

               #undef exprtk_loop
               #undef case_stmt
            }

            return std::numeric_limits<T>::quiet_NaN();
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_strswap;
         }

         inline bool valid() const exprtk_override
         {
            return initialised_ && binary_node<T>::valid();
         }

      private:

         swap_genstrings_node(const swap_genstrings_node<T>&) exprtk_delete;
         swap_genstrings_node<T>& operator=(const swap_genstrings_node<T>&) exprtk_delete;

         str_base_ptr str0_base_ptr_;
         str_base_ptr str1_base_ptr_;
         range_ptr    str0_range_ptr_;
         range_ptr    str1_range_ptr_;
         bool         initialised_;
      };

      template <typename T>
      class stringvar_size_node exprtk_final : public expression_node<T>
      {
      public:

         static const std::string null_value;

         explicit stringvar_size_node()
         : value_(&null_value)
         {}

         explicit stringvar_size_node(std::string& v)
         : value_(&v)
         {}

         inline T value() const exprtk_override
         {
            return T((*value_).size());
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_stringvarsize;
         }

      private:

         const std::string* value_;
      };

      template <typename T>
      const std::string stringvar_size_node<T>::null_value = std::string("");

      template <typename T>
      class string_size_node exprtk_final : public expression_node<T>
      {
      public:

         typedef expression_node <T>* expression_ptr;
         typedef string_base_node<T>* str_base_ptr;
         typedef std::pair<expression_ptr,bool>  branch_t;

         explicit string_size_node(expression_ptr branch)
         : str_base_ptr_(0)
         {
            construct_branch_pair(branch_, branch);

            if (is_generally_string_node(branch_.first))
            {
               str_base_ptr_ = dynamic_cast<str_base_ptr>(branch_.first);
            }

            assert(valid());
         }

         inline T value() const exprtk_override
         {
            branch_.first->value();
            return T(str_base_ptr_->size());
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_stringsize;
         }

         inline bool valid() const exprtk_override
         {
            return str_base_ptr_;
         }

         void collect_nodes(typename expression_node<T>::noderef_list_t& node_delete_list) exprtk_override
         {
            expression_node<T>::ndb_t::collect(branch_, node_delete_list);
         }

         std::size_t node_depth() const exprtk_override
         {
            return expression_node<T>::ndb_t::compute_node_depth(branch_);
         }

      private:

         branch_t     branch_;
         str_base_ptr str_base_ptr_;
      };

      struct asn_assignment
      {
         static inline void execute(std::string& s, char_cptr data, const std::size_t size)
         { s.assign(data,size); }
      };

      struct asn_addassignment
      {
         static inline void execute(std::string& s, char_cptr data, const std::size_t size)
         { s.append(data,size); }
      };

      template <typename T, typename AssignmentProcess = asn_assignment>
      class assignment_string_node exprtk_final
                                   : public binary_node     <T>
                                   , public string_base_node<T>
                                   , public range_interface <T>
      {
      public:

         typedef typename range_interface<T>::range_t range_t;
         typedef range_t*             range_ptr;
         typedef range_interface <T>  irange_t;
         typedef irange_t*            irange_ptr;
         typedef expression_node <T>* expression_ptr;
         typedef stringvar_node  <T>* strvar_node_ptr;
         typedef string_base_node<T>* str_base_ptr;

         using binary_node<T>::branch;

         assignment_string_node(const operator_type& opr,
                                expression_ptr branch0,
                                expression_ptr branch1)
         : binary_node<T>(opr, branch0, branch1)
         , initialised_(false)
         , str0_base_ptr_ (0)
         , str1_base_ptr_ (0)
         , str0_node_ptr_ (0)
         , str1_range_ptr_(0)
         {
            if (is_string_node(branch(0)))
            {
               str0_node_ptr_ = static_cast<strvar_node_ptr>(branch(0));
               str0_base_ptr_ = dynamic_cast<str_base_ptr>(branch(0));
            }

            if (is_generally_string_node(branch(1)))
            {
               str1_base_ptr_ = dynamic_cast<str_base_ptr>(branch(1));

               if (0 == str1_base_ptr_)
                  return;

               irange_ptr range = dynamic_cast<irange_ptr>(branch(1));

               if (0 == range)
                  return;

               str1_range_ptr_ = &(range->range_ref());
            }

            initialised_ = str0_base_ptr_  &&
                           str1_base_ptr_  &&
                           str0_node_ptr_  &&
                           str1_range_ptr_ ;

            assert(valid());
         }

         inline T value() const exprtk_override
         {
            branch(1)->value();

            std::size_t r0 = 0;
            std::size_t r1 = 0;

            const range_t& range = (*str1_range_ptr_);

            if (range(r0, r1, str1_base_ptr_->size()))
            {
               AssignmentProcess::execute(
                  str0_node_ptr_->ref(),
                  str1_base_ptr_->base() + r0, (r1 - r0));

               branch(0)->value();
            }

            return std::numeric_limits<T>::quiet_NaN();
         }

         std::string str() const exprtk_override
         {
            return str0_node_ptr_->str();
         }

         char_cptr base() const exprtk_override
         {
           return str0_node_ptr_->base();
         }

         std::size_t size() const exprtk_override
         {
            return str0_node_ptr_->size();
         }

         range_t& range_ref() exprtk_override
         {
            return str0_node_ptr_->range_ref();
         }

         const range_t& range_ref() const exprtk_override
         {
            return str0_node_ptr_->range_ref();
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_strass;
         }

         inline bool valid() const exprtk_override
         {
            return initialised_ && binary_node<T>::valid();
         }

      private:

         bool            initialised_;
         str_base_ptr    str0_base_ptr_;
         str_base_ptr    str1_base_ptr_;
         strvar_node_ptr str0_node_ptr_;
         range_ptr       str1_range_ptr_;
      };

      template <typename T, typename AssignmentProcess = asn_assignment>
      class assignment_string_range_node exprtk_final
                                         : public binary_node     <T>
                                         , public string_base_node<T>
                                         , public range_interface <T>
      {
      public:

         typedef typename range_interface<T>::range_t range_t;
         typedef range_t*              range_ptr;
         typedef range_interface  <T>  irange_t;
         typedef irange_t*             irange_ptr;
         typedef expression_node  <T>* expression_ptr;
         typedef stringvar_node   <T>* strvar_node_ptr;
         typedef string_range_node<T>* str_rng_node_ptr;
         typedef string_base_node <T>* str_base_ptr;

         using binary_node<T>::branch;

         assignment_string_range_node(const operator_type& opr,
                                      expression_ptr branch0,
                                      expression_ptr branch1)
         : binary_node<T>(opr, branch0, branch1)
         , initialised_(false)
         , str0_base_ptr_    (0)
         , str1_base_ptr_    (0)
         , str0_rng_node_ptr_(0)
         , str0_range_ptr_   (0)
         , str1_range_ptr_   (0)
         {
            if (is_string_range_node(branch(0)))
            {
               str0_rng_node_ptr_ = static_cast<str_rng_node_ptr>(branch(0));
               str0_base_ptr_     = dynamic_cast<str_base_ptr>(branch(0));
               irange_ptr range   = dynamic_cast<irange_ptr>(branch(0));

               if (0 == range)
                  return;

               str0_range_ptr_ = &(range->range_ref());
            }

            if (is_generally_string_node(branch(1)))
            {
               str1_base_ptr_ = dynamic_cast<str_base_ptr>(branch(1));

               if (0 == str1_base_ptr_)
                  return;

               irange_ptr range = dynamic_cast<irange_ptr>(branch(1));

               if (0 == range)
                  return;

               str1_range_ptr_ = &(range->range_ref());
            }

            initialised_ = str0_base_ptr_     &&
                           str1_base_ptr_     &&
                           str0_rng_node_ptr_ &&
                           str0_range_ptr_    &&
                           str1_range_ptr_    ;

            assert(valid());
         }

         inline T value() const exprtk_override
         {
            branch(0)->value();
            branch(1)->value();

            std::size_t s0_r0 = 0;
            std::size_t s0_r1 = 0;

            std::size_t s1_r0 = 0;
            std::size_t s1_r1 = 0;

            const range_t& range0 = (*str0_range_ptr_);
            const range_t& range1 = (*str1_range_ptr_);

            if (
                  range0(s0_r0, s0_r1, str0_base_ptr_->size()) &&
                  range1(s1_r0, s1_r1, str1_base_ptr_->size())
               )
            {
               const std::size_t size = std::min((s0_r1 - s0_r0), (s1_r1 - s1_r0));

               std::copy(
                  str1_base_ptr_->base() + s1_r0,
                  str1_base_ptr_->base() + s1_r0 + size,
                  const_cast<char_ptr>(base() + s0_r0));
            }

            return std::numeric_limits<T>::quiet_NaN();
         }

         std::string str() const exprtk_override
         {
            return str0_base_ptr_->str();
         }

         char_cptr base() const exprtk_override
         {
            return str0_base_ptr_->base();
         }

         std::size_t size() const exprtk_override
         {
            return str0_base_ptr_->size();
         }

         range_t& range_ref() exprtk_override
         {
            return str0_rng_node_ptr_->range_ref();
         }

         const range_t& range_ref() const exprtk_override
         {
            return str0_rng_node_ptr_->range_ref();
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_strass;
         }

         inline bool valid() const exprtk_override
         {
            return initialised_ && binary_node<T>::valid();
         }

      private:

         bool             initialised_;
         str_base_ptr     str0_base_ptr_;
         str_base_ptr     str1_base_ptr_;
         str_rng_node_ptr str0_rng_node_ptr_;
         range_ptr        str0_range_ptr_;
         range_ptr        str1_range_ptr_;
      };

      template <typename T>
      class conditional_string_node exprtk_final
                                    : public trinary_node    <T>
                                    , public string_base_node<T>
                                    , public range_interface <T>
      {
      public:

         typedef typename range_interface<T>::range_t range_t;
         typedef range_t*             range_ptr;
         typedef range_interface <T>  irange_t;
         typedef irange_t*            irange_ptr;
         typedef expression_node <T>* expression_ptr;
         typedef string_base_node<T>* str_base_ptr;

         conditional_string_node(expression_ptr condition,
                                 expression_ptr consequent,
                                 expression_ptr alternative)
         : trinary_node<T>(details::e_default, consequent, alternative, condition)
         , initialised_(false)
         , str0_base_ptr_ (0)
         , str1_base_ptr_ (0)
         , str0_range_ptr_(0)
         , str1_range_ptr_(0)
         , condition_  (condition  )
         , consequent_ (consequent )
         , alternative_(alternative)
         {
            range_.n0_c = std::make_pair<bool,std::size_t>(true,0);
            range_.n1_c = std::make_pair<bool,std::size_t>(true,0);

            range_.cache.first  = range_.n0_c.second;
            range_.cache.second = range_.n1_c.second;

            if (is_generally_string_node(trinary_node<T>::branch_[0].first))
            {
               str0_base_ptr_ = dynamic_cast<str_base_ptr>(trinary_node<T>::branch_[0].first);

               if (0 == str0_base_ptr_)
                  return;

               str0_range_ptr_ = dynamic_cast<irange_ptr>(trinary_node<T>::branch_[0].first);

               if (0 == str0_range_ptr_)
                  return;
            }

            if (is_generally_string_node(trinary_node<T>::branch_[1].first))
            {
               str1_base_ptr_ = dynamic_cast<str_base_ptr>(trinary_node<T>::branch_[1].first);

               if (0 == str1_base_ptr_)
                  return;

               str1_range_ptr_ = dynamic_cast<irange_ptr>(trinary_node<T>::branch_[1].first);

               if (0 == str1_range_ptr_)
                  return;
            }

            initialised_ = str0_base_ptr_  &&
                           str1_base_ptr_  &&
                           str0_range_ptr_ &&
                           str1_range_ptr_ ;

            assert(valid());
         }

         inline T value() const exprtk_override
         {
            std::size_t r0 = 0;
            std::size_t r1 = 0;

            if (is_true(condition_))
            {
               consequent_->value();

               const range_t& range = str0_range_ptr_->range_ref();

               if (range(r0, r1, str0_base_ptr_->size()))
               {
                  const std::size_t size = (r1 - r0);

                  value_.assign(str0_base_ptr_->base() + r0, size);

                  range_.n1_c.second  = value_.size();
                  range_.cache.second = range_.n1_c.second;

                  return T(1);
               }
            }
            else
            {
               alternative_->value();

               const range_t& range = str1_range_ptr_->range_ref();

               if (range(r0, r1, str1_base_ptr_->size()))
               {
                  const std::size_t size = (r1 - r0);

                  value_.assign(str1_base_ptr_->base() + r0, size);

                  range_.n1_c.second  = value_.size();
                  range_.cache.second = range_.n1_c.second;

                  return T(0);
               }
            }

            return std::numeric_limits<T>::quiet_NaN();
         }

         std::string str() const exprtk_override
         {
            return value_;
         }

         char_cptr base() const exprtk_override
         {
            return &value_[0];
         }

         std::size_t size() const exprtk_override
         {
            return value_.size();
         }

         range_t& range_ref() exprtk_override
         {
            return range_;
         }

         const range_t& range_ref() const exprtk_override
         {
            return range_;
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_strcondition;
         }

         inline bool valid() const exprtk_override
         {
            return
               initialised_                         &&
               condition_  && condition_  ->valid() &&
               consequent_ && consequent_ ->valid() &&
               alternative_&& alternative_->valid() ;
         }

      private:

         bool initialised_;
         str_base_ptr str0_base_ptr_;
         str_base_ptr str1_base_ptr_;
         irange_ptr   str0_range_ptr_;
         irange_ptr   str1_range_ptr_;
         mutable range_t     range_;
         mutable std::string value_;

         expression_ptr condition_;
         expression_ptr consequent_;
         expression_ptr alternative_;
      };

      template <typename T>
      class cons_conditional_str_node exprtk_final
                                      : public binary_node     <T>
                                      , public string_base_node<T>
                                      , public range_interface <T>
      {
      public:

         typedef typename range_interface<T>::range_t range_t;
         typedef range_t*             range_ptr;
         typedef range_interface <T>  irange_t;
         typedef irange_t*            irange_ptr;
         typedef expression_node <T>* expression_ptr;
         typedef string_base_node<T>* str_base_ptr;

         using binary_node<T>::branch;

         cons_conditional_str_node(expression_ptr condition,
                                   expression_ptr consequent)
         : binary_node<T>(details::e_default, consequent, condition)
         , initialised_(false)
         , str0_base_ptr_ (0)
         , str0_range_ptr_(0)
         , condition_ (condition )
         , consequent_(consequent)
         {
            range_.n0_c = std::make_pair<bool,std::size_t>(true,0);
            range_.n1_c = std::make_pair<bool,std::size_t>(true,0);

            range_.cache.first  = range_.n0_c.second;
            range_.cache.second = range_.n1_c.second;

            if (is_generally_string_node(branch(0)))
            {
               str0_base_ptr_ = dynamic_cast<str_base_ptr>(branch(0));

               if (0 == str0_base_ptr_)
                  return;

               str0_range_ptr_ = dynamic_cast<irange_ptr>(branch(0));

               if (0 == str0_range_ptr_)
                  return;
            }

            initialised_ = str0_base_ptr_ && str0_range_ptr_ ;
            assert(valid());
         }

         inline T value() const exprtk_override
         {
            if (is_true(condition_))
            {
               consequent_->value();

               const range_t& range = str0_range_ptr_->range_ref();

               std::size_t r0 = 0;
               std::size_t r1 = 0;

               if (range(r0, r1, str0_base_ptr_->size()))
               {
                  const std::size_t size = (r1 - r0);

                  value_.assign(str0_base_ptr_->base() + r0, size);

                  range_.n1_c.second  = value_.size();
                  range_.cache.second = range_.n1_c.second;

                  return T(1);
               }
            }

            return std::numeric_limits<T>::quiet_NaN();
         }

         std::string str() const
         {
            return value_;
         }

         char_cptr base() const
         {
            return &value_[0];
         }

         std::size_t size() const
         {
            return value_.size();
         }

         range_t& range_ref()
         {
            return range_;
         }

         const range_t& range_ref() const
         {
            return range_;
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_strccondition;
         }

         inline bool valid() const exprtk_override
         {
            return
               initialised_                         &&
               condition_  && condition_  ->valid() &&
               consequent_ && consequent_ ->valid() ;
         }

      private:

         bool initialised_;
         str_base_ptr str0_base_ptr_;
         irange_ptr   str0_range_ptr_;
         mutable range_t     range_;
         mutable std::string value_;

         expression_ptr condition_;
         expression_ptr consequent_;
      };

      template <typename T, typename VarArgFunction>
      class str_vararg_node exprtk_final
                            : public expression_node <T>
                            , public string_base_node<T>
                            , public range_interface <T>
      {
      public:

         typedef typename range_interface<T>::range_t range_t;
         typedef range_t*             range_ptr;
         typedef range_interface <T>  irange_t;
         typedef irange_t*            irange_ptr;
         typedef expression_node <T>* expression_ptr;
         typedef string_base_node<T>* str_base_ptr;
         typedef std::pair<expression_ptr,bool> branch_t;

         template <typename Allocator,
                   template <typename, typename> class Sequence>
         explicit str_vararg_node(const Sequence<expression_ptr,Allocator>& arg_list)
         : initialised_(false)
         , str_base_ptr_ (0)
         , str_range_ptr_(0)
         {
            construct_branch_pair(final_node_, const_cast<expression_ptr>(arg_list.back()));

            if (0 == final_node_.first)
               return;
            else if (!is_generally_string_node(final_node_.first))
               return;

            str_base_ptr_ = dynamic_cast<str_base_ptr>(final_node_.first);

            if (0 == str_base_ptr_)
               return;

            str_range_ptr_ = dynamic_cast<irange_ptr>(final_node_.first);

            if (0 == str_range_ptr_)
               return;

            if (arg_list.size() > 1)
            {
               const std::size_t arg_list_size = arg_list.size() - 1;

               arg_list_.resize(arg_list_size);

               for (std::size_t i = 0; i < arg_list_size; ++i)
               {
                  if (arg_list[i] && arg_list[i]->valid())
                  {
                     construct_branch_pair(arg_list_[i], arg_list[i]);
                  }
                  else
                  {
                     arg_list_.clear();
                     return;
                  }
               }

               initialised_ = true;
            }

            initialised_ &= str_base_ptr_ && str_range_ptr_;
            assert(valid());
         }

         inline T value() const exprtk_override
         {
            if (!arg_list_.empty())
            {
               VarArgFunction::process(arg_list_);
            }

            final_node_.first->value();

            return std::numeric_limits<T>::quiet_NaN();
         }

         std::string str() const exprtk_override
         {
            return str_base_ptr_->str();
         }

         char_cptr base() const exprtk_override
         {
            return str_base_ptr_->base();
         }

         std::size_t size() const exprtk_override
         {
            return str_base_ptr_->size();
         }

         range_t& range_ref() exprtk_override
         {
            return str_range_ptr_->range_ref();
         }

         const range_t& range_ref() const exprtk_override
         {
            return str_range_ptr_->range_ref();
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_stringvararg;
         }

         inline bool valid() const exprtk_override
         {
            return
               initialised_ &&
               final_node_.first && final_node_.first->valid();
         }

         void collect_nodes(typename expression_node<T>::noderef_list_t& node_delete_list) exprtk_override
         {
            expression_node<T>::ndb_t::collect(final_node_ , node_delete_list);
            expression_node<T>::ndb_t::collect(arg_list_   , node_delete_list);
         }

         std::size_t node_depth() const exprtk_override
         {
            return std::max(
               expression_node<T>::ndb_t::compute_node_depth(final_node_),
               expression_node<T>::ndb_t::compute_node_depth(arg_list_  ));
         }

      private:

         bool                  initialised_;
         branch_t              final_node_;
         str_base_ptr          str_base_ptr_;
         irange_ptr            str_range_ptr_;
         std::vector<branch_t> arg_list_;
      };
      #endif

      template <typename T>
      class assert_node exprtk_final : public expression_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         typedef std::pair<expression_ptr,bool> branch_t;
         typedef string_base_node<T>* str_base_ptr;
         typedef assert_check::assert_context assert_context_t;

         assert_node(expression_ptr   assert_condition_node,
                     expression_ptr   assert_message_node,
                     assert_check_ptr assert_check,
                     assert_context_t context)
         : assert_message_str_base_(0)
         , assert_check_(assert_check)
         , context_(context)
         {
            construct_branch_pair(assert_condition_node_, assert_condition_node);
            construct_branch_pair(assert_message_node_  , assert_message_node  );

            #ifndef exprtk_disable_string_capabilities
            if (
                  assert_message_node_.first &&
                  details::is_generally_string_node(assert_message_node_.first)
               )
            {
               assert_message_str_base_ = dynamic_cast<str_base_ptr>(assert_message_node_.first);
            }
            #endif

            assert(valid());
         }

         inline T value() const exprtk_override
         {
            if (details::is_true(assert_condition_node_.first->value()))
            {
               return T(1);
            }

            #ifndef exprtk_disable_string_capabilities
            if (assert_message_node_.first)
            {
               assert_message_node_.first->value();
               assert(assert_message_str_base_);
               context_.message = assert_message_str_base_->str();
            }
            #endif

            assert_check_->handle_assert(context_);
            return T(0);
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_assert;
         }

         inline bool valid() const exprtk_override
         {
            return (
                     assert_check_ &&
                     assert_condition_node_.first &&
                     assert_condition_node_.first->valid()
                   ) &&
                   (
                     (0 == assert_message_node_.first) ||
                     (
                       assert_message_node_.first &&
                       assert_message_str_base_   &&
                       assert_message_node_.first->valid() &&
                       details::is_generally_string_node(assert_message_node_.first)
                     )
                   );
         }

         void collect_nodes(typename expression_node<T>::noderef_list_t& node_delete_list) exprtk_override
         {
            expression_node<T>::ndb_t::collect(assert_condition_node_, node_delete_list);
            expression_node<T>::ndb_t::collect(assert_message_node_  , node_delete_list);
         }

         std::size_t node_depth() const exprtk_override
         {
            return expression_node<T>::ndb_t::compute_node_depth
               (assert_condition_node_, assert_message_node_);
         }

      private:

         branch_t         assert_condition_node_;
         branch_t         assert_message_node_;
         str_base_ptr     assert_message_str_base_;
         assert_check_ptr assert_check_;
         mutable assert_context_t context_;
      };

      template <typename T, std::size_t N>
      inline T axn(const T a, const T x)
      {
         // a*x^n
         return a * exprtk::details::numeric::fast_exp<T,N>::result(x);
      }

      template <typename T, std::size_t N>
      inline T axnb(const T a, const T x, const T b)
      {
         // a*x^n+b
         return a * exprtk::details::numeric::fast_exp<T,N>::result(x) + b;
      }

      template <typename T>
      struct sf_base
      {
         typedef typename details::functor_t<T>::Type Type;
         typedef typename details::functor_t<T> functor_t;
         typedef typename functor_t::qfunc_t quaternary_functor_t;
         typedef typename functor_t::tfunc_t trinary_functor_t;
         typedef typename functor_t::bfunc_t binary_functor_t;
         typedef typename functor_t::ufunc_t unary_functor_t;
      };

      #define define_sfop3(NN, OP0, OP1)                 \
      template <typename T>                              \
      struct sf##NN##_op : public sf_base<T>             \
      {                                                  \
         typedef typename sf_base<T>::Type const Type;   \
         static inline T process(Type x, Type y, Type z) \
         {                                               \
            return (OP0);                                \
         }                                               \
         static inline std::string id()                  \
         {                                               \
            return (OP1);                                \
         }                                               \
      };                                                 \

      define_sfop3(00,(x + y) / z       ,"(t+t)/t")
      define_sfop3(01,(x + y) * z       ,"(t+t)*t")
      define_sfop3(02,(x + y) - z       ,"(t+t)-t")
      define_sfop3(03,(x + y) + z       ,"(t+t)+t")
      define_sfop3(04,(x - y) + z       ,"(t-t)+t")
      define_sfop3(05,(x - y) / z       ,"(t-t)/t")
      define_sfop3(06,(x - y) * z       ,"(t-t)*t")
      define_sfop3(07,(x * y) + z       ,"(t*t)+t")
      define_sfop3(08,(x * y) - z       ,"(t*t)-t")
      define_sfop3(09,(x * y) / z       ,"(t*t)/t")
      define_sfop3(10,(x * y) * z       ,"(t*t)*t")
      define_sfop3(11,(x / y) + z       ,"(t/t)+t")
      define_sfop3(12,(x / y) - z       ,"(t/t)-t")
      define_sfop3(13,(x / y) / z       ,"(t/t)/t")
      define_sfop3(14,(x / y) * z       ,"(t/t)*t")
      define_sfop3(15,x / (y + z)       ,"t/(t+t)")
      define_sfop3(16,x / (y - z)       ,"t/(t-t)")
      define_sfop3(17,x / (y * z)       ,"t/(t*t)")
      define_sfop3(18,x / (y / z)       ,"t/(t/t)")
      define_sfop3(19,x * (y + z)       ,"t*(t+t)")
      define_sfop3(20,x * (y - z)       ,"t*(t-t)")
      define_sfop3(21,x * (y * z)       ,"t*(t*t)")
      define_sfop3(22,x * (y / z)       ,"t*(t/t)")
      define_sfop3(23,x - (y + z)       ,"t-(t+t)")
      define_sfop3(24,x - (y - z)       ,"t-(t-t)")
      define_sfop3(25,x - (y / z)       ,"t-(t/t)")
      define_sfop3(26,x - (y * z)       ,"t-(t*t)")
      define_sfop3(27,x + (y * z)       ,"t+(t*t)")
      define_sfop3(28,x + (y / z)       ,"t+(t/t)")
      define_sfop3(29,x + (y + z)       ,"t+(t+t)")
      define_sfop3(30,x + (y - z)       ,"t+(t-t)")
      define_sfop3(31,(axnb<T,2>(x,y,z)),"       ")
      define_sfop3(32,(axnb<T,3>(x,y,z)),"       ")
      define_sfop3(33,(axnb<T,4>(x,y,z)),"       ")
      define_sfop3(34,(axnb<T,5>(x,y,z)),"       ")
      define_sfop3(35,(axnb<T,6>(x,y,z)),"       ")
      define_sfop3(36,(axnb<T,7>(x,y,z)),"       ")
      define_sfop3(37,(axnb<T,8>(x,y,z)),"       ")
      define_sfop3(38,(axnb<T,9>(x,y,z)),"       ")
      define_sfop3(39,x * numeric::log(y)   + z,"")
      define_sfop3(40,x * numeric::log(y)   - z,"")
      define_sfop3(41,x * numeric::log10(y) + z,"")
      define_sfop3(42,x * numeric::log10(y) - z,"")
      define_sfop3(43,x * numeric::sin(y) + z  ,"")
      define_sfop3(44,x * numeric::sin(y) - z  ,"")
      define_sfop3(45,x * numeric::cos(y) + z  ,"")
      define_sfop3(46,x * numeric::cos(y) - z  ,"")
      define_sfop3(47,details::is_true(x) ? y : z,"")

      #define define_sfop4(NN, OP0, OP1)                         \
      template <typename T>                                      \
      struct sf##NN##_op : public sf_base<T>                     \
      {                                                          \
         typedef typename sf_base<T>::Type const Type;           \
         static inline T process(Type x, Type y, Type z, Type w) \
         {                                                       \
            return (OP0);                                        \
         }                                                       \
         static inline std::string id()                          \
         {                                                       \
            return (OP1);                                        \
         }                                                       \
      };                                                         \

      define_sfop4(48,(x + ((y + z) / w)),"t+((t+t)/t)")
      define_sfop4(49,(x + ((y + z) * w)),"t+((t+t)*t)")
      define_sfop4(50,(x + ((y - z) / w)),"t+((t-t)/t)")
      define_sfop4(51,(x + ((y - z) * w)),"t+((t-t)*t)")
      define_sfop4(52,(x + ((y * z) / w)),"t+((t*t)/t)")
      define_sfop4(53,(x + ((y * z) * w)),"t+((t*t)*t)")
      define_sfop4(54,(x + ((y / z) + w)),"t+((t/t)+t)")
      define_sfop4(55,(x + ((y / z) / w)),"t+((t/t)/t)")
      define_sfop4(56,(x + ((y / z) * w)),"t+((t/t)*t)")
      define_sfop4(57,(x - ((y + z) / w)),"t-((t+t)/t)")
      define_sfop4(58,(x - ((y + z) * w)),"t-((t+t)*t)")
      define_sfop4(59,(x - ((y - z) / w)),"t-((t-t)/t)")
      define_sfop4(60,(x - ((y - z) * w)),"t-((t-t)*t)")
      define_sfop4(61,(x - ((y * z) / w)),"t-((t*t)/t)")
      define_sfop4(62,(x - ((y * z) * w)),"t-((t*t)*t)")
      define_sfop4(63,(x - ((y / z) / w)),"t-((t/t)/t)")
      define_sfop4(64,(x - ((y / z) * w)),"t-((t/t)*t)")
      define_sfop4(65,(((x + y) * z) - w),"((t+t)*t)-t")
      define_sfop4(66,(((x - y) * z) - w),"((t-t)*t)-t")
      define_sfop4(67,(((x * y) * z) - w),"((t*t)*t)-t")
      define_sfop4(68,(((x / y) * z) - w),"((t/t)*t)-t")
      define_sfop4(69,(((x + y) / z) - w),"((t+t)/t)-t")
      define_sfop4(70,(((x - y) / z) - w),"((t-t)/t)-t")
      define_sfop4(71,(((x * y) / z) - w),"((t*t)/t)-t")
      define_sfop4(72,(((x / y) / z) - w),"((t/t)/t)-t")
      define_sfop4(73,((x * y) + (z * w)),"(t*t)+(t*t)")
      define_sfop4(74,((x * y) - (z * w)),"(t*t)-(t*t)")
      define_sfop4(75,((x * y) + (z / w)),"(t*t)+(t/t)")
      define_sfop4(76,((x * y) - (z / w)),"(t*t)-(t/t)")
      define_sfop4(77,((x / y) + (z / w)),"(t/t)+(t/t)")
      define_sfop4(78,((x / y) - (z / w)),"(t/t)-(t/t)")
      define_sfop4(79,((x / y) - (z * w)),"(t/t)-(t*t)")
      define_sfop4(80,(x / (y + (z * w))),"t/(t+(t*t))")
      define_sfop4(81,(x / (y - (z * w))),"t/(t-(t*t))")
      define_sfop4(82,(x * (y + (z * w))),"t*(t+(t*t))")
      define_sfop4(83,(x * (y - (z * w))),"t*(t-(t*t))")

      define_sfop4(84,(axn<T,2>(x,y) + axn<T,2>(z,w)),"")
      define_sfop4(85,(axn<T,3>(x,y) + axn<T,3>(z,w)),"")
      define_sfop4(86,(axn<T,4>(x,y) + axn<T,4>(z,w)),"")
      define_sfop4(87,(axn<T,5>(x,y) + axn<T,5>(z,w)),"")
      define_sfop4(88,(axn<T,6>(x,y) + axn<T,6>(z,w)),"")
      define_sfop4(89,(axn<T,7>(x,y) + axn<T,7>(z,w)),"")
      define_sfop4(90,(axn<T,8>(x,y) + axn<T,8>(z,w)),"")
      define_sfop4(91,(axn<T,9>(x,y) + axn<T,9>(z,w)),"")
      define_sfop4(92,((details::is_true(x) && details::is_true(y)) ? z : w),"")
      define_sfop4(93,((details::is_true(x) || details::is_true(y)) ? z : w),"")
      define_sfop4(94,((x <  y) ? z : w),"")
      define_sfop4(95,((x <= y) ? z : w),"")
      define_sfop4(96,((x >  y) ? z : w),"")
      define_sfop4(97,((x >= y) ? z : w),"")
      define_sfop4(98,(details::is_true(numeric::equal(x,y)) ? z : w),"")
      define_sfop4(99,(x * numeric::sin(y) + z * numeric::cos(w)),"")

      define_sfop4(ext00,((x + y) - (z * w)),"(t+t)-(t*t)")
      define_sfop4(ext01,((x + y) - (z / w)),"(t+t)-(t/t)")
      define_sfop4(ext02,((x + y) + (z * w)),"(t+t)+(t*t)")
      define_sfop4(ext03,((x + y) + (z / w)),"(t+t)+(t/t)")
      define_sfop4(ext04,((x - y) + (z * w)),"(t-t)+(t*t)")
      define_sfop4(ext05,((x - y) + (z / w)),"(t-t)+(t/t)")
      define_sfop4(ext06,((x - y) - (z * w)),"(t-t)-(t*t)")
      define_sfop4(ext07,((x - y) - (z / w)),"(t-t)-(t/t)")
      define_sfop4(ext08,((x + y) - (z - w)),"(t+t)-(t-t)")
      define_sfop4(ext09,((x + y) + (z - w)),"(t+t)+(t-t)")
      define_sfop4(ext10,((x + y) + (z + w)),"(t+t)+(t+t)")
      define_sfop4(ext11,((x + y) * (z - w)),"(t+t)*(t-t)")
      define_sfop4(ext12,((x + y) / (z - w)),"(t+t)/(t-t)")
      define_sfop4(ext13,((x - y) - (z + w)),"(t-t)-(t+t)")
      define_sfop4(ext14,((x - y) + (z + w)),"(t-t)+(t+t)")
      define_sfop4(ext15,((x - y) * (z + w)),"(t-t)*(t+t)")
      define_sfop4(ext16,((x - y) / (z + w)),"(t-t)/(t+t)")
      define_sfop4(ext17,((x * y) - (z + w)),"(t*t)-(t+t)")
      define_sfop4(ext18,((x / y) - (z + w)),"(t/t)-(t+t)")
      define_sfop4(ext19,((x * y) + (z + w)),"(t*t)+(t+t)")
      define_sfop4(ext20,((x / y) + (z + w)),"(t/t)+(t+t)")
      define_sfop4(ext21,((x * y) + (z - w)),"(t*t)+(t-t)")
      define_sfop4(ext22,((x / y) + (z - w)),"(t/t)+(t-t)")
      define_sfop4(ext23,((x * y) - (z - w)),"(t*t)-(t-t)")
      define_sfop4(ext24,((x / y) - (z - w)),"(t/t)-(t-t)")
      define_sfop4(ext25,((x + y) * (z * w)),"(t+t)*(t*t)")
      define_sfop4(ext26,((x + y) * (z / w)),"(t+t)*(t/t)")
      define_sfop4(ext27,((x + y) / (z * w)),"(t+t)/(t*t)")
      define_sfop4(ext28,((x + y) / (z / w)),"(t+t)/(t/t)")
      define_sfop4(ext29,((x - y) / (z * w)),"(t-t)/(t*t)")
      define_sfop4(ext30,((x - y) / (z / w)),"(t-t)/(t/t)")
      define_sfop4(ext31,((x - y) * (z * w)),"(t-t)*(t*t)")
      define_sfop4(ext32,((x - y) * (z / w)),"(t-t)*(t/t)")
      define_sfop4(ext33,((x * y) * (z + w)),"(t*t)*(t+t)")
      define_sfop4(ext34,((x / y) * (z + w)),"(t/t)*(t+t)")
      define_sfop4(ext35,((x * y) / (z + w)),"(t*t)/(t+t)")
      define_sfop4(ext36,((x / y) / (z + w)),"(t/t)/(t+t)")
      define_sfop4(ext37,((x * y) / (z - w)),"(t*t)/(t-t)")
      define_sfop4(ext38,((x / y) / (z - w)),"(t/t)/(t-t)")
      define_sfop4(ext39,((x * y) * (z - w)),"(t*t)*(t-t)")
      define_sfop4(ext40,((x * y) / (z * w)),"(t*t)/(t*t)")
      define_sfop4(ext41,((x / y) * (z / w)),"(t/t)*(t/t)")
      define_sfop4(ext42,((x / y) * (z - w)),"(t/t)*(t-t)")
      define_sfop4(ext43,((x * y) * (z * w)),"(t*t)*(t*t)")
      define_sfop4(ext44,(x + (y * (z / w))),"t+(t*(t/t))")
      define_sfop4(ext45,(x - (y * (z / w))),"t-(t*(t/t))")
      define_sfop4(ext46,(x + (y / (z * w))),"t+(t/(t*t))")
      define_sfop4(ext47,(x - (y / (z * w))),"t-(t/(t*t))")
      define_sfop4(ext48,(((x - y) - z) * w),"((t-t)-t)*t")
      define_sfop4(ext49,(((x - y) - z) / w),"((t-t)-t)/t")
      define_sfop4(ext50,(((x - y) + z) * w),"((t-t)+t)*t")
      define_sfop4(ext51,(((x - y) + z) / w),"((t-t)+t)/t")
      define_sfop4(ext52,((x + (y - z)) * w),"(t+(t-t))*t")
      define_sfop4(ext53,((x + (y - z)) / w),"(t+(t-t))/t")
      define_sfop4(ext54,((x + y) / (z + w)),"(t+t)/(t+t)")
      define_sfop4(ext55,((x - y) / (z - w)),"(t-t)/(t-t)")
      define_sfop4(ext56,((x + y) * (z + w)),"(t+t)*(t+t)")
      define_sfop4(ext57,((x - y) * (z - w)),"(t-t)*(t-t)")
      define_sfop4(ext58,((x - y) + (z - w)),"(t-t)+(t-t)")
      define_sfop4(ext59,((x - y) - (z - w)),"(t-t)-(t-t)")
      define_sfop4(ext60,((x / y) + (z * w)),"(t/t)+(t*t)")
      define_sfop4(ext61,(((x * y) * z) / w),"((t*t)*t)/t")

      #undef define_sfop3
      #undef define_sfop4

      template <typename T, typename SpecialFunction>
      class sf3_node exprtk_final : public trinary_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;

         sf3_node(const operator_type& opr,
                  expression_ptr branch0,
                  expression_ptr branch1,
                  expression_ptr branch2)
         : trinary_node<T>(opr, branch0, branch1, branch2)
         {}

         inline T value() const exprtk_override
         {
            const T x = trinary_node<T>::branch_[0].first->value();
            const T y = trinary_node<T>::branch_[1].first->value();
            const T z = trinary_node<T>::branch_[2].first->value();

            return SpecialFunction::process(x, y, z);
         }
      };

      template <typename T, typename SpecialFunction>
      class sf4_node exprtk_final : public quaternary_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;

         sf4_node(const operator_type& opr,
                  expression_ptr branch0,
                  expression_ptr branch1,
                  expression_ptr branch2,
                  expression_ptr branch3)
         : quaternary_node<T>(opr, branch0, branch1, branch2, branch3)
         {}

         inline T value() const exprtk_override
         {
            const T x = quaternary_node<T>::branch_[0].first->value();
            const T y = quaternary_node<T>::branch_[1].first->value();
            const T z = quaternary_node<T>::branch_[2].first->value();
            const T w = quaternary_node<T>::branch_[3].first->value();

            return SpecialFunction::process(x, y, z, w);
         }
      };

      template <typename T, typename SpecialFunction>
      class sf3_var_node exprtk_final : public expression_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;

         sf3_var_node(const T& v0, const T& v1, const T& v2)
         : v0_(v0)
         , v1_(v1)
         , v2_(v2)
         {}

         inline T value() const exprtk_override
         {
            return SpecialFunction::process(v0_, v1_, v2_);
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_trinary;
         }

      private:

         sf3_var_node(const sf3_var_node<T,SpecialFunction>&) exprtk_delete;
         sf3_var_node<T,SpecialFunction>& operator=(const sf3_var_node<T,SpecialFunction>&) exprtk_delete;

         const T& v0_;
         const T& v1_;
         const T& v2_;
      };

      template <typename T, typename SpecialFunction>
      class sf4_var_node exprtk_final : public expression_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;

         sf4_var_node(const T& v0, const T& v1, const T& v2, const T& v3)
         : v0_(v0)
         , v1_(v1)
         , v2_(v2)
         , v3_(v3)
         {}

         inline T value() const exprtk_override
         {
            return SpecialFunction::process(v0_, v1_, v2_, v3_);
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_trinary;
         }

      private:

         sf4_var_node(const sf4_var_node<T,SpecialFunction>&) exprtk_delete;
         sf4_var_node<T,SpecialFunction>& operator=(const sf4_var_node<T,SpecialFunction>&) exprtk_delete;

         const T& v0_;
         const T& v1_;
         const T& v2_;
         const T& v3_;
      };

      template <typename T, typename VarArgFunction>
      class vararg_node exprtk_final : public expression_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         typedef std::pair<expression_ptr,bool> branch_t;

         template <typename Allocator,
                   template <typename, typename> class Sequence>
         explicit vararg_node(const Sequence<expression_ptr,Allocator>& arg_list)
         : initialised_(false)
         {
            arg_list_.resize(arg_list.size());

            for (std::size_t i = 0; i < arg_list.size(); ++i)
            {
               if (arg_list[i] && arg_list[i]->valid())
               {
                  construct_branch_pair(arg_list_[i],arg_list[i]);
               }
               else
               {
                  arg_list_.clear();
                  return;
               }
            }

            initialised_ = (arg_list_.size() == arg_list.size());
            assert(valid());
         }

         inline T value() const exprtk_override
         {
            return VarArgFunction::process(arg_list_);
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_vararg;
         }

         inline bool valid() const exprtk_override
         {
            return initialised_;
         }

         void collect_nodes(typename expression_node<T>::noderef_list_t& node_delete_list) exprtk_override
         {
            expression_node<T>::ndb_t::collect(arg_list_, node_delete_list);
         }

         std::size_t node_depth() const exprtk_override
         {
            return expression_node<T>::ndb_t::compute_node_depth(arg_list_);
         }

         std::size_t size() const
         {
            return arg_list_.size();
         }

         expression_ptr operator[](const std::size_t& index) const
         {
            return arg_list_[index].first;
         }

      private:

         std::vector<branch_t> arg_list_;
         bool initialised_;
      };

      template <typename T, typename VarArgFunction>
      class vararg_varnode exprtk_final : public expression_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;

         template <typename Allocator,
                   template <typename, typename> class Sequence>
         explicit vararg_varnode(const Sequence<expression_ptr,Allocator>& arg_list)
         : initialised_(false)
         {
            arg_list_.resize(arg_list.size());

            for (std::size_t i = 0; i < arg_list.size(); ++i)
            {
               if (arg_list[i] && arg_list[i]->valid() && is_variable_node(arg_list[i]))
               {
                  variable_node<T>* var_node_ptr = static_cast<variable_node<T>*>(arg_list[i]);
                  arg_list_[i] = (&var_node_ptr->ref());
               }
               else
               {
                  arg_list_.clear();
                  return;
               }
            }

            initialised_ = (arg_list.size() == arg_list_.size());
            assert(valid());
         }

         inline T value() const exprtk_override
         {
            return VarArgFunction::process(arg_list_);
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_vararg;
         }

         inline bool valid() const exprtk_override
         {
            return initialised_;
         }

      private:

         std::vector<const T*> arg_list_;
         bool initialised_;
      };

      template <typename T, typename VecFunction>
      class vectorize_node exprtk_final : public expression_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         typedef std::pair<expression_ptr,bool> branch_t;

         explicit vectorize_node(const expression_ptr v)
         : ivec_ptr_(0)
         {
            construct_branch_pair(v_, v);

            if (is_ivector_node(v_.first))
            {
               ivec_ptr_ = dynamic_cast<vector_interface<T>*>(v_.first);
            }
         }

         inline T value() const exprtk_override
         {
            v_.first->value();
            return VecFunction::process(ivec_ptr_);
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_vecfunc;
         }

         inline bool valid() const exprtk_override
         {
            return ivec_ptr_ && v_.first && v_.first->valid();
         }

         void collect_nodes(typename expression_node<T>::noderef_list_t& node_delete_list) exprtk_override
         {
            expression_node<T>::ndb_t::collect(v_, node_delete_list);
         }

         std::size_t node_depth() const exprtk_override
         {
            return expression_node<T>::ndb_t::compute_node_depth(v_);
         }

      private:

         vector_interface<T>* ivec_ptr_;
         branch_t                    v_;
      };

      template <typename T>
      class assignment_node exprtk_final : public binary_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         using binary_node<T>::branch;

         assignment_node(const operator_type& opr,
                         expression_ptr branch0,
                         expression_ptr branch1)
         : binary_node<T>(opr, branch0, branch1)
         , var_node_ptr_(0)
         {
            if (is_variable_node(branch(0)))
            {
               var_node_ptr_ = static_cast<variable_node<T>*>(branch(0));
            }
         }

         inline T value() const exprtk_override
         {
            T& result = var_node_ptr_->ref();
               result = branch(1)->value();

            return result;
         }

         inline bool valid() const exprtk_override
         {
            return var_node_ptr_ && binary_node<T>::valid();
         }

      private:

         variable_node<T>* var_node_ptr_;
      };

      template <typename T>
      class assignment_vec_elem_node exprtk_final : public binary_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         using binary_node<T>::branch;

         assignment_vec_elem_node(const operator_type& opr,
                                  expression_ptr branch0,
                                  expression_ptr branch1)
         : binary_node<T>(opr, branch0, branch1)
         , vec_node_ptr_(0)
         {
            if (is_vector_elem_node(branch(0)))
            {
               vec_node_ptr_ = static_cast<vector_elem_node<T>*>(branch(0));
            }

            assert(valid());
         }

         inline T value() const exprtk_override
         {
            T& result = vec_node_ptr_->ref();
               result = branch(1)->value();

            return result;
         }

         inline bool valid() const exprtk_override
         {
            return vec_node_ptr_ && binary_node<T>::valid();
         }

      private:

         vector_elem_node<T>* vec_node_ptr_;
      };

      template <typename T>
      class assignment_vec_elem_rtc_node exprtk_final : public binary_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         using binary_node<T>::branch;

         assignment_vec_elem_rtc_node(const operator_type& opr,
                                      expression_ptr branch0,
                                      expression_ptr branch1)
         : binary_node<T>(opr, branch0, branch1)
         , vec_node_ptr_(0)
         {
            if (is_vector_elem_rtc_node(branch(0)))
            {
               vec_node_ptr_ = static_cast<vector_elem_rtc_node<T>*>(branch(0));
            }

            assert(valid());
         }

         inline T value() const exprtk_override
         {
            T& result = vec_node_ptr_->ref();
               result = branch(1)->value();

            return result;
         }

         inline bool valid() const exprtk_override
         {
            return vec_node_ptr_ && binary_node<T>::valid();
         }

      private:

         vector_elem_rtc_node<T>* vec_node_ptr_;
      };

      template <typename T>
      class assignment_rebasevec_elem_node exprtk_final : public binary_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         using expression_node<T>::branch;

         assignment_rebasevec_elem_node(const operator_type& opr,
                                        expression_ptr branch0,
                                        expression_ptr branch1)
         : binary_node<T>(opr, branch0, branch1)
         , rbvec_node_ptr_(0)
         {
            if (is_rebasevector_elem_node(branch(0)))
            {
               rbvec_node_ptr_ = static_cast<rebasevector_elem_node<T>*>(branch(0));
            }

            assert(valid());
         }

         inline T value() const exprtk_override
         {
            T& result = rbvec_node_ptr_->ref();
               result = branch(1)->value();

            return result;
         }

         inline bool valid() const exprtk_override
         {
            return rbvec_node_ptr_ && binary_node<T>::valid();
         }

      private:

         rebasevector_elem_node<T>* rbvec_node_ptr_;
      };

      template <typename T>
      class assignment_rebasevec_elem_rtc_node exprtk_final : public binary_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         using expression_node<T>::branch;

         assignment_rebasevec_elem_rtc_node(const operator_type& opr,
                                            expression_ptr branch0,
                                            expression_ptr branch1)
         : binary_node<T>(opr, branch0, branch1)
         , rbvec_node_ptr_(0)
         {
            if (is_rebasevector_elem_rtc_node(branch(0)))
            {
               rbvec_node_ptr_ = static_cast<rebasevector_elem_rtc_node<T>*>(branch(0));
            }

            assert(valid());
         }

         inline T value() const exprtk_override
         {
            T& result = rbvec_node_ptr_->ref();
               result = branch(1)->value();

            return result;
         }

         inline bool valid() const exprtk_override
         {
            return rbvec_node_ptr_ && binary_node<T>::valid();
         }

      private:

         rebasevector_elem_rtc_node<T>* rbvec_node_ptr_;
      };

      template <typename T>
      class assignment_rebasevec_celem_node exprtk_final : public binary_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         using binary_node<T>::branch;

         assignment_rebasevec_celem_node(const operator_type& opr,
                                         expression_ptr branch0,
                                         expression_ptr branch1)
         : binary_node<T>(opr, branch0, branch1)
         , rbvec_node_ptr_(0)
         {
            if (is_rebasevector_celem_node(branch(0)))
            {
               rbvec_node_ptr_ = static_cast<rebasevector_celem_node<T>*>(branch(0));
            }

            assert(valid());
         }

         inline T value() const exprtk_override
         {
            T& result = rbvec_node_ptr_->ref();
               result = branch(1)->value();

            return result;
         }

         inline bool valid() const exprtk_override
         {
            return rbvec_node_ptr_ && binary_node<T>::valid();
         }

      private:

         rebasevector_celem_node<T>* rbvec_node_ptr_;
      };

      template <typename T>
      class assignment_vec_node exprtk_final
                                : public binary_node     <T>
                                , public vector_interface<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         typedef vector_node<T>*     vector_node_ptr;
         typedef vec_data_store<T>   vds_t;

         using binary_node<T>::branch;

         assignment_vec_node(const operator_type& opr,
                             expression_ptr branch0,
                             expression_ptr branch1)
         : binary_node<T>(opr, branch0, branch1)
         , vec_node_ptr_(0)
         {
            if (is_vector_node(branch(0)))
            {
               vec_node_ptr_ = static_cast<vector_node<T>*>(branch(0));
               vds()         = vec_node_ptr_->vds();
            }

            assert(valid());
         }

         inline T value() const exprtk_override
         {
            const T v = branch(1)->value();

            T* vec = vds().data();

            loop_unroll::details lud(size());
            const T* upper_bound = vec + lud.upper_bound;

            while (vec < upper_bound)
            {
               #define exprtk_loop(N) \
               vec[N] = v;            \

               exprtk_loop( 0) exprtk_loop( 1)
               exprtk_loop( 2) exprtk_loop( 3)
               #ifndef exprtk_disable_superscalar_unroll
               exprtk_loop( 4) exprtk_loop( 5)
               exprtk_loop( 6) exprtk_loop( 7)
               exprtk_loop( 8) exprtk_loop( 9)
               exprtk_loop(10) exprtk_loop(11)
               exprtk_loop(12) exprtk_loop(13)
               exprtk_loop(14) exprtk_loop(15)
               #endif

               vec += lud.batch_size;
            }

            switch (lud.remainder)
            {
               #define case_stmt(N) \
               case N : *vec++ = v; \
               exprtk_fallthrough   \

               #ifndef exprtk_disable_superscalar_unroll
               case_stmt(15) case_stmt(14)
               case_stmt(13) case_stmt(12)
               case_stmt(11) case_stmt(10)
               case_stmt( 9) case_stmt( 8)
               case_stmt( 7) case_stmt( 6)
               case_stmt( 5) case_stmt( 4)
               #endif
               case_stmt( 3) case_stmt( 2)
               case 1 : *vec++ = v;
            }

            #undef exprtk_loop
            #undef case_stmt

            return vec_node_ptr_->value();
         }

         vector_node_ptr vec() const exprtk_override
         {
            return vec_node_ptr_;
         }

         vector_node_ptr vec() exprtk_override
         {
            return vec_node_ptr_;
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_vecvalass;
         }

         inline bool valid() const exprtk_override
         {
            return
               vec_node_ptr_ &&
               (vds().size() <= vec_node_ptr_->vec_holder().base_size()) &&
               binary_node<T>::valid();
         }

         std::size_t size() const exprtk_override
         {
            return vec_node_ptr_->vec_holder().size();
         }

         std::size_t base_size() const exprtk_override
         {
            return vec_node_ptr_->vec_holder().base_size();
         }

         vds_t& vds() exprtk_override
         {
            return vds_;
         }

         const vds_t& vds() const exprtk_override
         {
            return vds_;
         }

      private:

         vector_node<T>* vec_node_ptr_;
         vds_t           vds_;
      };

      template <typename T>
      class assignment_vecvec_node exprtk_final
                                   : public binary_node     <T>
                                   , public vector_interface<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         typedef vector_node<T>*     vector_node_ptr;
         typedef vec_data_store<T>   vds_t;

         using binary_node<T>::branch;

         assignment_vecvec_node(const operator_type& opr,
                                expression_ptr branch0,
                                expression_ptr branch1)
         : binary_node<T>(opr, branch0, branch1)
         , vec0_node_ptr_(0)
         , vec1_node_ptr_(0)
         , initialised_(false)
         , src_is_ivec_(false)
         {
            if (is_vector_node(branch(0)))
            {
               vec0_node_ptr_ = static_cast<vector_node<T>*>(branch(0));
               vds()          = vec0_node_ptr_->vds();
            }

            if (is_vector_node(branch(1)))
            {
               vec1_node_ptr_ = static_cast<vector_node<T>*>(branch(1));
               vds_t::match_sizes(vds(),vec1_node_ptr_->vds());
            }
            else if (is_ivector_node(branch(1)))
            {
               vector_interface<T>* vi = reinterpret_cast<vector_interface<T>*>(0);

               if (0 != (vi = dynamic_cast<vector_interface<T>*>(branch(1))))
               {
                  vec1_node_ptr_ = vi->vec();

                  if (!vi->side_effect())
                  {
                     vi->vds()    = vds();
                     src_is_ivec_ = true;
                  }
                  else
                     vds_t::match_sizes(vds(),vi->vds());
               }
            }

            initialised_ =
               vec0_node_ptr_               &&
               vec1_node_ptr_               &&
               (size() <= base_size())      &&
               (vds_.size() <= base_size()) &&
               binary_node<T>::valid();

            assert(valid());
         }

         inline T value() const exprtk_override
         {
            branch(1)->value();

            if (src_is_ivec_)
               return vec0_node_ptr_->value();

            T* vec0 = vec0_node_ptr_->vds().data();
            T* vec1 = vec1_node_ptr_->vds().data();

            loop_unroll::details lud(size());
            const T* upper_bound = vec0 + lud.upper_bound;

            while (vec0 < upper_bound)
            {
               #define exprtk_loop(N) \
               vec0[N] = vec1[N];     \

               exprtk_loop( 0) exprtk_loop( 1)
               exprtk_loop( 2) exprtk_loop( 3)
               #ifndef exprtk_disable_superscalar_unroll
               exprtk_loop( 4) exprtk_loop( 5)
               exprtk_loop( 6) exprtk_loop( 7)
               exprtk_loop( 8) exprtk_loop( 9)
               exprtk_loop(10) exprtk_loop(11)
               exprtk_loop(12) exprtk_loop(13)
               exprtk_loop(14) exprtk_loop(15)
               #endif

               vec0 += lud.batch_size;
               vec1 += lud.batch_size;
            }

            switch (lud.remainder)
            {
               #define case_stmt(N,fall_through) \
               case N : *vec0++ = *vec1++;       \
               fall_through                      \

               #ifndef exprtk_disable_superscalar_unroll
               case_stmt(15, exprtk_fallthrough) case_stmt(14, exprtk_fallthrough)
               case_stmt(13, exprtk_fallthrough) case_stmt(12, exprtk_fallthrough)
               case_stmt(11, exprtk_fallthrough) case_stmt(10, exprtk_fallthrough)
               case_stmt( 9, exprtk_fallthrough) case_stmt( 8, exprtk_fallthrough)
               case_stmt( 7, exprtk_fallthrough) case_stmt( 6, exprtk_fallthrough)
               case_stmt( 5, exprtk_fallthrough) case_stmt( 4, exprtk_fallthrough)
               #endif
               case_stmt( 3, exprtk_fallthrough) case_stmt( 2, exprtk_fallthrough)
               case_stmt( 1, (void)0;)
            }

            #undef exprtk_loop
            #undef case_stmt

            return vec0_node_ptr_->value();
         }

         vector_node_ptr vec() exprtk_override
         {
            return vec0_node_ptr_;
         }

         vector_node_ptr vec() const exprtk_override
         {
            return vec0_node_ptr_;
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_vecvecass;
         }

         inline bool valid() const exprtk_override
         {
            return initialised_;
         }

         std::size_t size() const exprtk_override
         {
            return std::min(
               vec0_node_ptr_->vec_holder().size(),
               vec1_node_ptr_->vec_holder().size());
         }

         std::size_t base_size() const exprtk_override
         {
            return std::min(
               vec0_node_ptr_->vec_holder().base_size(),
               vec1_node_ptr_->vec_holder().base_size());
         }

         vds_t& vds() exprtk_override
         {
            return vds_;
         }

         const vds_t& vds() const exprtk_override
         {
            return vds_;
         }

      private:

         vector_node<T>* vec0_node_ptr_;
         vector_node<T>* vec1_node_ptr_;
         bool            initialised_;
         bool            src_is_ivec_;
         vds_t           vds_;
      };

      template <typename T, typename Operation>
      class assignment_op_node exprtk_final : public binary_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         using binary_node<T>::branch;

         assignment_op_node(const operator_type& opr,
                            expression_ptr branch0,
                            expression_ptr branch1)
         : binary_node<T>(opr, branch0, branch1)
         , var_node_ptr_(0)
         {
            if (is_variable_node(branch(0)))
            {
               var_node_ptr_ = static_cast<variable_node<T>*>(branch(0));
            }

            assert(valid());
         }

         inline T value() const exprtk_override
         {
            T& v = var_node_ptr_->ref();
            v = Operation::process(v,branch(1)->value());

            return v;
         }

         inline bool valid() const exprtk_override
         {
            return var_node_ptr_ && binary_node<T>::valid();
         }

      private:

         variable_node<T>* var_node_ptr_;
      };

      template <typename T, typename Operation>
      class assignment_vec_elem_op_node exprtk_final : public binary_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         using binary_node<T>::branch;

         assignment_vec_elem_op_node(const operator_type& opr,
                                     expression_ptr branch0,
                                     expression_ptr branch1)
         : binary_node<T>(opr, branch0, branch1)
         , vec_node_ptr_(0)
         {
            if (is_vector_elem_node(branch(0)))
            {
               vec_node_ptr_ = static_cast<vector_elem_node<T>*>(branch(0));
            }

            assert(valid());
         }

         inline T value() const exprtk_override
         {
            T& v = vec_node_ptr_->ref();
               v = Operation::process(v,branch(1)->value());

            return v;
         }

         inline bool valid() const exprtk_override
         {
            return vec_node_ptr_ && binary_node<T>::valid();
         }

      private:

         vector_elem_node<T>* vec_node_ptr_;
      };

      template <typename T, typename Operation>
      class assignment_vec_elem_op_rtc_node exprtk_final : public binary_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         using binary_node<T>::branch;

         assignment_vec_elem_op_rtc_node(const operator_type& opr,
                                         expression_ptr branch0,
                                         expression_ptr branch1)
         : binary_node<T>(opr, branch0, branch1)
         , vec_node_ptr_(0)
         {
            if (is_vector_elem_rtc_node(branch(0)))
            {
               vec_node_ptr_ = static_cast<vector_elem_rtc_node<T>*>(branch(0));
            }

            assert(valid());
         }

         inline T value() const exprtk_override
         {
            T& v = vec_node_ptr_->ref();
               v = Operation::process(v,branch(1)->value());

            return v;
         }

         inline bool valid() const exprtk_override
         {
            return vec_node_ptr_ && binary_node<T>::valid();
         }

      private:

         vector_elem_rtc_node<T>* vec_node_ptr_;
      };

      template <typename T, typename Operation>
      class assignment_vec_celem_op_rtc_node exprtk_final : public binary_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         using binary_node<T>::branch;

         assignment_vec_celem_op_rtc_node(const operator_type& opr,
                                          expression_ptr branch0,
                                          expression_ptr branch1)
         : binary_node<T>(opr, branch0, branch1)
         , vec_node_ptr_(0)
         {
            if (is_vector_celem_rtc_node(branch(0)))
            {
               vec_node_ptr_ = static_cast<vector_celem_rtc_node<T>*>(branch(0));
            }

            assert(valid());
         }

         inline T value() const exprtk_override
         {
            T& v = vec_node_ptr_->ref();
               v = Operation::process(v,branch(1)->value());

            return v;
         }

         inline bool valid() const exprtk_override
         {
            return vec_node_ptr_ && binary_node<T>::valid();
         }

      private:

         vector_celem_rtc_node<T>* vec_node_ptr_;
      };

      template <typename T, typename Operation>
      class assignment_rebasevec_elem_op_node exprtk_final : public binary_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         using binary_node<T>::branch;

         assignment_rebasevec_elem_op_node(const operator_type& opr,
                                           expression_ptr branch0,
                                           expression_ptr branch1)
         : binary_node<T>(opr, branch0, branch1)
         , rbvec_node_ptr_(0)
         {
            if (is_rebasevector_elem_node(branch(0)))
            {
               rbvec_node_ptr_ = static_cast<rebasevector_elem_node<T>*>(branch(0));
            }

            assert(valid());
         }

         inline T value() const exprtk_override
         {
            T& v = rbvec_node_ptr_->ref();
               v = Operation::process(v,branch(1)->value());

            return v;
         }

         inline bool valid() const exprtk_override
         {
            return rbvec_node_ptr_ && binary_node<T>::valid();
         }

      private:

         rebasevector_elem_node<T>* rbvec_node_ptr_;
      };

      template <typename T, typename Operation>
      class assignment_rebasevec_celem_op_node exprtk_final : public binary_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         using binary_node<T>::branch;

         assignment_rebasevec_celem_op_node(const operator_type& opr,
                                            expression_ptr branch0,
                                            expression_ptr branch1)
         : binary_node<T>(opr, branch0, branch1)
         , rbvec_node_ptr_(0)
         {
            if (is_rebasevector_celem_node(branch(0)))
            {
               rbvec_node_ptr_ = static_cast<rebasevector_celem_node<T>*>(branch(0));
            }

            assert(valid());
         }

         inline T value() const exprtk_override
         {
            T& v = rbvec_node_ptr_->ref();
               v = Operation::process(v,branch(1)->value());

            return v;
         }

         inline bool valid() const exprtk_override
         {
            return rbvec_node_ptr_ && binary_node<T>::valid();
         }

      private:

         rebasevector_celem_node<T>* rbvec_node_ptr_;
      };

      template <typename T, typename Operation>
      class assignment_rebasevec_elem_op_rtc_node exprtk_final : public binary_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         using binary_node<T>::branch;

         assignment_rebasevec_elem_op_rtc_node(const operator_type& opr,
                                               expression_ptr branch0,
                                               expression_ptr branch1)
         : binary_node<T>(opr, branch0, branch1)
         , rbvec_node_ptr_(0)
         {
            if (is_rebasevector_elem_rtc_node(branch(0)))
            {
               rbvec_node_ptr_ = static_cast<rebasevector_elem_rtc_node<T>*>(branch(0));
            }

            assert(valid());
         }

         inline T value() const exprtk_override
         {
            T& v = rbvec_node_ptr_->ref();
               v = Operation::process(v,branch(1)->value());

            return v;
         }

         inline bool valid() const exprtk_override
         {
            return rbvec_node_ptr_ && binary_node<T>::valid();
         }

      private:

         rebasevector_elem_rtc_node<T>* rbvec_node_ptr_;
      };

      template <typename T, typename Operation>
      class assignment_rebasevec_celem_op_rtc_node exprtk_final : public binary_node<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         using binary_node<T>::branch;

         assignment_rebasevec_celem_op_rtc_node(const operator_type& opr,
                                                expression_ptr branch0,
                                                expression_ptr branch1)
         : binary_node<T>(opr, branch0, branch1)
         , rbvec_node_ptr_(0)
         {
            if (is_rebasevector_celem_rtc_node(branch(0)))
            {
               rbvec_node_ptr_ = static_cast<rebasevector_celem_rtc_node<T>*>(branch(0));
            }

            assert(valid());
         }

         inline T value() const exprtk_override
         {
            T& v = rbvec_node_ptr_->ref();
               v = Operation::process(v,branch(1)->value());

            return v;
         }

         inline bool valid() const exprtk_override
         {
            return rbvec_node_ptr_ && binary_node<T>::valid();
         }

      private:

         rebasevector_celem_rtc_node<T>* rbvec_node_ptr_;
      };

      template <typename T, typename Operation>
      class assignment_vec_op_node exprtk_final
                                   : public binary_node     <T>
                                   , public vector_interface<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         typedef vector_node<T>*     vector_node_ptr;
         typedef vec_data_store<T>   vds_t;

         using binary_node<T>::branch;

         assignment_vec_op_node(const operator_type& opr,
                                expression_ptr branch0,
                                expression_ptr branch1)
         : binary_node<T>(opr, branch0, branch1)
         , vec_node_ptr_(0)
         {
            if (is_vector_node(branch(0)))
            {
               vec_node_ptr_ = static_cast<vector_node<T>*>(branch(0));
               vds()         = vec_node_ptr_->vds();
            }

            assert(valid());
         }

         inline T value() const exprtk_override
         {
            const T v = branch(1)->value();

            T* vec = vds().data();

            loop_unroll::details lud(size());
            const T* upper_bound = vec + lud.upper_bound;

            while (vec < upper_bound)
            {
               #define exprtk_loop(N)       \
               Operation::assign(vec[N],v); \

               exprtk_loop( 0) exprtk_loop( 1)
               exprtk_loop( 2) exprtk_loop( 3)
               #ifndef exprtk_disable_superscalar_unroll
               exprtk_loop( 4) exprtk_loop( 5)
               exprtk_loop( 6) exprtk_loop( 7)
               exprtk_loop( 8) exprtk_loop( 9)
               exprtk_loop(10) exprtk_loop(11)
               exprtk_loop(12) exprtk_loop(13)
               exprtk_loop(14) exprtk_loop(15)
               #endif

               vec += lud.batch_size;
            }

            switch (lud.remainder)
            {
               #define case_stmt(N,fall_through)     \
               case N : Operation::assign(*vec++,v); \
               fall_through                          \

               #ifndef exprtk_disable_superscalar_unroll
               case_stmt(15, exprtk_fallthrough) case_stmt(14, exprtk_fallthrough)
               case_stmt(13, exprtk_fallthrough) case_stmt(12, exprtk_fallthrough)
               case_stmt(11, exprtk_fallthrough) case_stmt(10, exprtk_fallthrough)
               case_stmt( 9, exprtk_fallthrough) case_stmt( 8, exprtk_fallthrough)
               case_stmt( 7, exprtk_fallthrough) case_stmt( 6, exprtk_fallthrough)
               case_stmt( 5, exprtk_fallthrough) case_stmt( 4, exprtk_fallthrough)
               #endif
               case_stmt( 3, exprtk_fallthrough) case_stmt( 2, exprtk_fallthrough)
               case_stmt( 1, (void)0;)
            }

            #undef exprtk_loop
            #undef case_stmt

            return vec_node_ptr_->value();
         }

         vector_node_ptr vec() const exprtk_override
         {
            return vec_node_ptr_;
         }

         vector_node_ptr vec() exprtk_override
         {
            return vec_node_ptr_;
         }

         inline typename expression_node<T>::node_type type() const exprtk_override
         {
            return expression_node<T>::e_vecopvalass;
         }

         inline bool valid() const exprtk_override
         {
            return
               vec_node_ptr_           &&
               (size() <= base_size()) &&
               binary_node<T>::valid() ;
         }

         std::size_t size() const exprtk_override
         {
            return vec_node_ptr_->vec_holder().size();
         }

         std::size_t base_size() const exprtk_override
         {
            return vec_node_ptr_->vec_holder().base_size();
         }

         vds_t& vds() exprtk_override
         {
            return vds_;
         }

         const vds_t& vds() const exprtk_override
         {
            return vds_;
         }

         bool side_effect() const exprtk_override
         {
            return true;
         }

      private:

         vector_node<T>* vec_node_ptr_;
         vds_t           vds_;
      };

      template <typename T, typename Operation>
      class assignment_vecvec_op_node exprtk_final
                                      : public binary_node     <T>
                                      , public vector_interface<T>
      {
      public:

         typedef expression_node<T>* expression_ptr;
         typedef vector_node<T>*     vector_node_ptr;
         typedef vec_data_store<T>   vds_t;

         using binary_node<T>::branch;

         assignment_vecvec_op_node(const operator_type& opr,
                                   expression_ptr branch0,
                                   expression_ptr branch1)
         : binary_node<T>(opr, branch0, branch1)
         , vec0_node_ptr_(0)
         , vec1_node_ptr_(0)
         , initialised_(false)
         {
            if (is_vector_node(branch(0)))
            {
               vec0_node_ptr_ = static_cast<vector_node<T>*>(branch(0));
               vds()          = vec0_node_ptr_->vds();
            }

            if (is_vector_node(branch(1)))
            {
               vec1_node_ptr_ = static_cast<vector_node<T>*>(branch(1));
               vec1_node_ptr_->vds() = vds();
            }
            else if (is_ivector_node(branch(1)))
            {
               vector_interface<T>* vi = reinterpret_cast<vector_interface<T>*>(0);

               if (0 != (vi = dynamic_cast<vector_interface<T>*>(branch(1))))
               {
                  vec1_node_ptr_ = vi->vec();
                  vec1_node_ptr_->vds() = vi->vds();
               }
               else
                  vds_t::match_sizes(vds(),vec1_node_ptr_->vds());
            }

            initialised_ =
               vec0_node_ptr_          &&
               vec1_node_ptr_          &&
               (size() <= base_size()) &&
               binary_node<T>::valid();

            assert(valid());
         }

         inline T value() const exprtk_override
         {
            branch(0)->value();
            branch(1)->value();

                  T* vec0 = vec0_node_ptr_->vds().data();
            const T* vec1 = vec1_node_ptr_->vds().data();

            loop_unroll::details lud(size());
            const T* upper_bound = vec0 + lud.upper_bound;

            while (vec0 < upper_bound)
            {
               #define exprtk_loop(N)                          \
               vec0[N] = Operation::process(vec0[N], vec1[N]); \

               exprtk_loop( 0) exprtk_loop( 1)
               exprtk_loop( 2) exprtk_loop( 3)
               #ifndef exprtk_disable_superscalar_unroll
               exprtk_loop( 4) 

Coverage Report

Created: 2025-06-09 06:31