///////////////////////////////////////////////////////////////////////////////

/// \file regex_primitives.hpp

/// Contains the syntax elements for writing static regular expressions.

//

//  Copyright 2008 Eric Niebler. Distributed under the Boost

//  Software License, Version 1.0. (See accompanying file

//  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

#ifndef BOOST_XPRESSIVE_REGEX_PRIMITIVES_HPP_EAN_10_04_2005

#define BOOST_XPRESSIVE_REGEX_PRIMITIVES_HPP_EAN_10_04_2005

#include <vector>

#include <climits>

#include <boost/config.hpp>

#include <boost/assert.hpp>

#include <boost/mpl/if.hpp>

#include <boost/mpl/and.hpp>

#include <boost/mpl/assert.hpp>

#include <boost/detail/workaround.hpp>

#include <boost/preprocessor/cat.hpp>

#include <boost/xpressive/detail/detail_fwd.hpp>

#include <boost/xpressive/detail/core/matchers.hpp>

#include <boost/xpressive/detail/core/regex_domain.hpp>

#include <boost/xpressive/detail/utility/ignore_unused.hpp>

// Doxygen can't handle proto :-(

#ifndef BOOST_XPRESSIVE_DOXYGEN_INVOKED

# include <boost/proto/core.hpp>

# include <boost/proto/transform/arg.hpp>

# include <boost/proto/transform/when.hpp>

# include <boost/xpressive/detail/core/icase.hpp>

# include <boost/xpressive/detail/static/compile.hpp>

# include <boost/xpressive/detail/static/modifier.hpp>

#endif

namespace boost { namespace xpressive { namespace detail

{

    typedef assert_word_placeholder<word_boundary<mpl::true_> > assert_word_boundary;

    typedef assert_word_placeholder<word_begin> assert_word_begin;

    typedef assert_word_placeholder<word_end> assert_word_end;

    // workaround msvc-7.1 bug with function pointer types

    // within function types:

    #if BOOST_WORKAROUND(BOOST_MSVC, == 1310)

    #define mark_number(x) proto::call<mark_number(x)>

    #define minus_one() proto::make<minus_one()>

    #endif

    struct push_back : proto::callable

    {

        typedef int result_type;

        template<typename Subs>

        int operator ()(Subs &subs, int i) const

        {

            subs.push_back(i);

            return i;

        }

    };

    struct mark_number : proto::callable

    {

        typedef int result_type;

        template<typename Expr>

        int operator ()(Expr const &expr) const

        {

            return expr.mark_number_;

        }

    };

    typedef mpl::int_<-1> minus_one;

    // s1 or -s1

    struct SubMatch

      : proto::or_<

            proto::when<basic_mark_tag,                push_back(proto::_data, mark_number(proto::_value))   >

          , proto::when<proto::negate<basic_mark_tag>, push_back(proto::_data, minus_one())                  >

        >

    {};

    struct SubMatchList

      : proto::or_<SubMatch, proto::comma<SubMatchList, SubMatch> >

    {};

    template<typename Subs>

    typename enable_if<

        mpl::and_<proto::is_expr<Subs>, proto::matches<Subs, SubMatchList> >

      , std::vector<int>

    >::type

    to_vector(Subs const &subs)

    {

        std::vector<int> subs_;

        SubMatchList()(subs, 0, subs_);

        return subs_;

    }

    #if BOOST_WORKAROUND(BOOST_MSVC, == 1310)

    #undef mark_number

    #undef minus_one

    #endif

    // replace "Expr" with "keep(*State) >> Expr"

    struct skip_primitives : proto::transform<skip_primitives>

    {

        template<typename Expr, typename State, typename Data>

        struct impl : proto::transform_impl<Expr, State, Data>

        {

            typedef

                typename proto::shift_right<

                    typename proto::unary_expr<

                        keeper_tag

                      , typename proto::dereference<State>::type

                    >::type

                  , Expr

                >::type

            result_type;

            result_type operator ()(

                typename impl::expr_param expr

              , typename impl::state_param state

              , typename impl::data_param

            ) const

            {

                result_type that = {{{state}}, expr};

                return that;

            }

        };

    };

    struct Primitives

      : proto::or_<

            proto::terminal<proto::_>

          , proto::comma<proto::_, proto::_>

          , proto::subscript<proto::terminal<set_initializer>, proto::_>

          , proto::assign<proto::terminal<set_initializer>, proto::_>

          , proto::assign<proto::terminal<attribute_placeholder<proto::_> >, proto::_>

          , proto::complement<Primitives>

        >

    {};

    struct SkipGrammar

      : proto::or_<

            proto::when<Primitives, skip_primitives>

          , proto::assign<proto::terminal<mark_placeholder>, SkipGrammar>   // don't "skip" mark tags

          , proto::subscript<SkipGrammar, proto::_>                         // don't put skips in actions

          , proto::binary_expr<modifier_tag, proto::_, SkipGrammar>         // don't skip modifiers

          , proto::unary_expr<lookbehind_tag, proto::_>                     // don't skip lookbehinds

          , proto::nary_expr<proto::_, proto::vararg<SkipGrammar> >         // everything else is fair game!

        >

    {};

    template<typename Skip>

    struct skip_directive

    {

        typedef typename proto::result_of::as_expr<Skip>::type skip_type;

        skip_directive(Skip const &skip)

          : skip_(proto::as_expr(skip))

        {}

        template<typename Sig>

        struct result {};

        template<typename This, typename Expr>

        struct result<This(Expr)>

        {

            typedef

                SkipGrammar::impl<

                    typename proto::result_of::as_expr<Expr>::type

                  , skip_type const &

                  , mpl::void_ &

                >

            skip_transform;

            typedef

                typename proto::shift_right<

                    typename skip_transform::result_type

                  , typename proto::dereference<skip_type>::type

                >::type

            type;

        };

        template<typename Expr>

        typename result<skip_directive(Expr)>::type

        operator ()(Expr const &expr) const

        {

            mpl::void_ ignore;

            typedef result<skip_directive(Expr)> result_fun;

            typename result_fun::type that = {

                typename result_fun::skip_transform()(proto::as_expr(expr), this->skip_, ignore)

              , {skip_}

            };

            return that;

        }

    private:

        skip_type skip_;

    };

/*

///////////////////////////////////////////////////////////////////////////////

/// INTERNAL ONLY

// BOOST_XPRESSIVE_GLOBAL

//  for defining globals that neither violate the One Definition Rule nor

//  lead to undefined behavior due to global object initialization order.

//#define BOOST_XPRESSIVE_GLOBAL(type, name, init)                                        \

//    namespace detail                                                                    \

//    {                                                                                   \

//        template<int Dummy>                                                             \

//        struct BOOST_PP_CAT(global_pod_, name)                                          \

//        {                                                                               \

//            static type const value;                                                    \

//        private:                                                                        \

//            union type_must_be_pod                                                      \

//            {                                                                           \

//                type t;                                                                 \

//                char ch;                                                                \

//            } u;                                                                        \

//        };                                                                              \

//        template<int Dummy>                                                             \

//        type const BOOST_PP_CAT(global_pod_, name)<Dummy>::value = init;                \

//    }                                                                                   \

//    type const &name = detail::BOOST_PP_CAT(global_pod_, name)<0>::value

*/

} // namespace detail

/// INTERNAL ONLY (for backwards compatibility)

unsigned int const repeat_max = UINT_MAX-1;

///////////////////////////////////////////////////////////////////////////////

/// \brief For infinite repetition of a sub-expression.

///

/// Magic value used with the repeat\<\>() function template

/// to specify an unbounded repeat. Use as: repeat<17, inf>('a').

/// The equivalent in perl is /a{17,}/.

unsigned int const inf = UINT_MAX-1;

/// INTERNAL ONLY (for backwards compatibility)

proto::terminal<detail::epsilon_matcher>::type const epsilon = {{}};

///////////////////////////////////////////////////////////////////////////////

/// \brief Successfully matches nothing.

///

/// Successfully matches a zero-width sequence. nil always succeeds and

/// never consumes any characters.

proto::terminal<detail::epsilon_matcher>::type const nil = {{}};

///////////////////////////////////////////////////////////////////////////////

/// \brief Matches an alpha-numeric character.

///

/// The regex traits are used to determine which characters are alpha-numeric.

/// To match any character that is not alpha-numeric, use ~alnum.

///

/// \attention alnum is equivalent to /[[:alnum:]]/ in perl. ~alnum is equivalent

/// to /[[:^alnum:]]/ in perl.

proto::terminal<detail::posix_charset_placeholder>::type const alnum = {{"alnum", false}};

///////////////////////////////////////////////////////////////////////////////

/// \brief Matches an alphabetic character.

///

/// The regex traits are used to determine which characters are alphabetic.

/// To match any character that is not alphabetic, use ~alpha.

///

/// \attention alpha is equivalent to /[[:alpha:]]/ in perl. ~alpha is equivalent

/// to /[[:^alpha:]]/ in perl.

proto::terminal<detail::posix_charset_placeholder>::type const alpha = {{"alpha", false}};

///////////////////////////////////////////////////////////////////////////////

/// \brief Matches a blank (horizonal white-space) character.

///

/// The regex traits are used to determine which characters are blank characters.

/// To match any character that is not blank, use ~blank.

///

/// \attention blank is equivalent to /[[:blank:]]/ in perl. ~blank is equivalent

/// to /[[:^blank:]]/ in perl.

proto::terminal<detail::posix_charset_placeholder>::type const blank = {{"blank", false}};

///////////////////////////////////////////////////////////////////////////////

/// \brief Matches a control character.

///

/// The regex traits are used to determine which characters are control characters.

/// To match any character that is not a control character, use ~cntrl.

///

/// \attention cntrl is equivalent to /[[:cntrl:]]/ in perl. ~cntrl is equivalent

/// to /[[:^cntrl:]]/ in perl.

proto::terminal<detail::posix_charset_placeholder>::type const cntrl = {{"cntrl", false}};

///////////////////////////////////////////////////////////////////////////////

/// \brief Matches a digit character.

///

/// The regex traits are used to determine which characters are digits.

/// To match any character that is not a digit, use ~digit.

///

/// \attention digit is equivalent to /[[:digit:]]/ in perl. ~digit is equivalent

/// to /[[:^digit:]]/ in perl.

proto::terminal<detail::posix_charset_placeholder>::type const digit = {{"digit", false}};

///////////////////////////////////////////////////////////////////////////////

/// \brief Matches a graph character.

///

/// The regex traits are used to determine which characters are graphable.

/// To match any character that is not graphable, use ~graph.

///

/// \attention graph is equivalent to /[[:graph:]]/ in perl. ~graph is equivalent

/// to /[[:^graph:]]/ in perl.

proto::terminal<detail::posix_charset_placeholder>::type const graph = {{"graph", false}};

///////////////////////////////////////////////////////////////////////////////

/// \brief Matches a lower-case character.

///

/// The regex traits are used to determine which characters are lower-case.

/// To match any character that is not a lower-case character, use ~lower.

///

/// \attention lower is equivalent to /[[:lower:]]/ in perl. ~lower is equivalent

/// to /[[:^lower:]]/ in perl.

proto::terminal<detail::posix_charset_placeholder>::type const lower = {{"lower", false}};

///////////////////////////////////////////////////////////////////////////////

/// \brief Matches a printable character.

///

/// The regex traits are used to determine which characters are printable.

/// To match any character that is not printable, use ~print.

///

/// \attention print is equivalent to /[[:print:]]/ in perl. ~print is equivalent

/// to /[[:^print:]]/ in perl.

proto::terminal<detail::posix_charset_placeholder>::type const print = {{"print", false}};

///////////////////////////////////////////////////////////////////////////////

/// \brief Matches a punctuation character.

///

/// The regex traits are used to determine which characters are punctuation.

/// To match any character that is not punctuation, use ~punct.

///

/// \attention punct is equivalent to /[[:punct:]]/ in perl. ~punct is equivalent

/// to /[[:^punct:]]/ in perl.

proto::terminal<detail::posix_charset_placeholder>::type const punct = {{"punct", false}};

///////////////////////////////////////////////////////////////////////////////

/// \brief Matches a space character.

///

/// The regex traits are used to determine which characters are space characters.

/// To match any character that is not white-space, use ~space.

///

/// \attention space is equivalent to /[[:space:]]/ in perl. ~space is equivalent

/// to /[[:^space:]]/ in perl.

proto::terminal<detail::posix_charset_placeholder>::type const space = {{"space", false}};

///////////////////////////////////////////////////////////////////////////////

/// \brief Matches an upper-case character.

///

/// The regex traits are used to determine which characters are upper-case.

/// To match any character that is not upper-case, use ~upper.

///

/// \attention upper is equivalent to /[[:upper:]]/ in perl. ~upper is equivalent

/// to /[[:^upper:]]/ in perl.

proto::terminal<detail::posix_charset_placeholder>::type const upper = {{"upper", false}};

///////////////////////////////////////////////////////////////////////////////

/// \brief Matches a hexadecimal digit character.

///

/// The regex traits are used to determine which characters are hex digits.

/// To match any character that is not a hex digit, use ~xdigit.

///

/// \attention xdigit is equivalent to /[[:xdigit:]]/ in perl. ~xdigit is equivalent

/// to /[[:^xdigit:]]/ in perl.

proto::terminal<detail::posix_charset_placeholder>::type const xdigit = {{"xdigit", false}};

///////////////////////////////////////////////////////////////////////////////

/// \brief Beginning of sequence assertion.

///

/// For the character sequence [begin, end), 'bos' matches the

/// zero-width sub-sequence [begin, begin).

proto::terminal<detail::assert_bos_matcher>::type const bos = {{}};

///////////////////////////////////////////////////////////////////////////////

/// \brief End of sequence assertion.

///

/// For the character sequence [begin, end),

/// 'eos' matches the zero-width sub-sequence [end, end).

///

/// \attention Unlike the perl end of sequence assertion \$, 'eos' will

/// not match at the position [end-1, end-1) if *(end-1) is '\\n'. To

/// get that behavior, use (!_n >> eos).

proto::terminal<detail::assert_eos_matcher>::type const eos = {{}};

///////////////////////////////////////////////////////////////////////////////

/// \brief Beginning of line assertion.

///

/// 'bol' matches the zero-width sub-sequence

/// immediately following a logical newline sequence. The regex traits

/// is used to determine what constitutes a logical newline sequence.

proto::terminal<detail::assert_bol_placeholder>::type const bol = {{}};

///////////////////////////////////////////////////////////////////////////////

/// \brief End of line assertion.

///

/// 'eol' matches the zero-width sub-sequence

/// immediately preceeding a logical newline sequence. The regex traits

/// is used to determine what constitutes a logical newline sequence.

proto::terminal<detail::assert_eol_placeholder>::type const eol = {{}};

///////////////////////////////////////////////////////////////////////////////

/// \brief Beginning of word assertion.

///

/// 'bow' matches the zero-width sub-sequence

/// immediately following a non-word character and preceeding a word character.

/// The regex traits are used to determine what constitutes a word character.

proto::terminal<detail::assert_word_begin>::type const bow = {{}};

///////////////////////////////////////////////////////////////////////////////

/// \brief End of word assertion.

///

/// 'eow' matches the zero-width sub-sequence

/// immediately following a word character and preceeding a non-word character.

/// The regex traits are used to determine what constitutes a word character.

proto::terminal<detail::assert_word_end>::type const eow = {{}};

///////////////////////////////////////////////////////////////////////////////

/// \brief Word boundary assertion.

///

/// '_b' matches the zero-width sub-sequence at the beginning or the end of a word.

/// It is equivalent to (bow | eow). The regex traits are used to determine what

/// constitutes a word character. To match a non-word boundary, use ~_b.

///

/// \attention _b is like \\b in perl. ~_b is like \\B in perl.

proto::terminal<detail::assert_word_boundary>::type const _b = {{}};

///////////////////////////////////////////////////////////////////////////////

/// \brief Matches a word character.

///

/// '_w' matches a single word character. The regex traits are used to determine which

/// characters are word characters. Use ~_w to match a character that is not a word

/// character.

///

/// \attention _w is like \\w in perl. ~_w is like \\W in perl.

proto::terminal<detail::posix_charset_placeholder>::type const _w = {{"w", false}};

///////////////////////////////////////////////////////////////////////////////

/// \brief Matches a digit character.

///

/// '_d' matches a single digit character. The regex traits are used to determine which

/// characters are digits. Use ~_d to match a character that is not a digit

/// character.

///

/// \attention _d is like \\d in perl. ~_d is like \\D in perl.

proto::terminal<detail::posix_charset_placeholder>::type const _d = {{"d", false}};

///////////////////////////////////////////////////////////////////////////////

/// \brief Matches a space character.

///

/// '_s' matches a single space character. The regex traits are used to determine which

/// characters are space characters. Use ~_s to match a character that is not a space

/// character.

///

/// \attention _s is like \\s in perl. ~_s is like \\S in perl.

proto::terminal<detail::posix_charset_placeholder>::type const _s = {{"s", false}};

///////////////////////////////////////////////////////////////////////////////

/// \brief Matches a literal newline character, '\\n'.

///

/// '_n' matches a single newline character, '\\n'. Use ~_n to match a character

/// that is not a newline.

///

/// \attention ~_n is like '.' in perl without the /s modifier.

proto::terminal<char>::type const _n = {'\n'};

///////////////////////////////////////////////////////////////////////////////

/// \brief Matches a logical newline sequence.

///

/// '_ln' matches a logical newline sequence. This can be any character in the

/// line separator class, as determined by the regex traits, or the '\\r\\n' sequence.

/// For the purpose of back-tracking, '\\r\\n' is treated as a unit.

/// To match any one character that is not a logical newline, use ~_ln.

detail::logical_newline_xpression const _ln = {{}};

///////////////////////////////////////////////////////////////////////////////

/// \brief Matches any one character.

///

/// Match any character, similar to '.' in perl syntax with the /s modifier.

/// '_' matches any one character, including the newline.

///

/// \attention To match any character except the newline, use ~_n

proto::terminal<detail::any_matcher>::type const _ = {{}};

///////////////////////////////////////////////////////////////////////////////

/// \brief Reference to the current regex object

///

/// Useful when constructing recursive regular expression objects. The 'self'

/// identifier is a short-hand for the current regex object. For instance,

/// sregex rx = '(' >> (self | nil) >> ')'; will create a regex object that

/// matches balanced parens such as "((()))".

proto::terminal<detail::self_placeholder>::type const self = {{}};

///////////////////////////////////////////////////////////////////////////////

/// \brief Used to create character sets.

///

/// There are two ways to create character sets with the 'set' identifier. The

/// easiest is to create a comma-separated list of the characters in the set,

/// as in (set= 'a','b','c'). This set will match 'a', 'b', or 'c'. The other

/// way is to define the set as an argument to the set subscript operator.

/// For instance, set[ 'a' | range('b','c') | digit ] will match an 'a', 'b',

/// 'c' or a digit character.

///

/// To complement a set, apply the '~' operator. For instance, ~(set= 'a','b','c')

/// will match any character that is not an 'a', 'b', or 'c'.

///

/// Sets can be composed of other, possibly complemented, sets. For instance,

/// set[ ~digit | ~(set= 'a','b','c') ].

detail::set_initializer_type const set = {{}};

///////////////////////////////////////////////////////////////////////////////

/// \brief Sub-match placeholder type, used to create named captures in

/// static regexes.

///

/// \c mark_tag is the type of the global sub-match placeholders \c s0, \c s1, etc.. You

/// can use the \c mark_tag type to create your own sub-match placeholders with

/// more meaningful names. This is roughly equivalent to the "named capture"

/// feature of dynamic regular expressions.

///

/// To create a named sub-match placeholder, initialize it with a unique integer.

/// The integer must only be unique within the regex in which the placeholder

/// is used. Then you can use it within static regexes to created sub-matches

/// by assigning a sub-expression to it, or to refer back to already created

/// sub-matches.

/// 

/// \code

/// mark_tag number(1); // "number" is now equivalent to "s1"

/// // Match a number, followed by a space and the same number again

/// sregex rx = (number = +_d) >> ' ' >> number;

/// \endcode

///

/// After a successful \c regex_match() or \c regex_search(), the sub-match placeholder

/// can be used to index into the <tt>match_results\<\></tt> object to retrieve the

/// corresponding sub-match.

struct mark_tag

  : proto::extends<detail::basic_mark_tag, mark_tag, detail::regex_domain>

{

private:

    typedef proto::extends<detail::basic_mark_tag, mark_tag, detail::regex_domain> base_type;

    static detail::basic_mark_tag make_tag(int mark_nbr)

    {

        detail::basic_mark_tag mark = {{mark_nbr}};

        return mark;

    }

public:

    /// \brief Initialize a mark_tag placeholder

    /// \param mark_nbr An integer that uniquely identifies this \c mark_tag

    /// within the static regexes in which this \c mark_tag will be used.

    /// \pre <tt>mark_nbr \> 0</tt>

    mark_tag(int mark_nbr)

      : base_type(mark_tag::make_tag(mark_nbr))

    {

        // Marks numbers must be integers greater than 0.

        BOOST_ASSERT(mark_nbr > 0);

    }

    /// INTERNAL ONLY

    operator detail::basic_mark_tag const &() const

    {

        return this->proto_base();

    }

    BOOST_PROTO_EXTENDS_USING_ASSIGN_NON_DEPENDENT(mark_tag)

};

// This macro is used when declaring mark_tags that are global because

// it guarantees that they are statically initialized. That avoids

// order-of-initialization bugs. In user code, the simpler: mark_tag s0(0);

// would be preferable.

/// INTERNAL ONLY

#define BOOST_XPRESSIVE_GLOBAL_MARK_TAG(NAME, VALUE)                            \

    boost::xpressive::mark_tag::proto_base_expr const NAME = {{VALUE}}          \

    /**/

///////////////////////////////////////////////////////////////////////////////

/// \brief Sub-match placeholder, like $& in Perl

BOOST_XPRESSIVE_GLOBAL_MARK_TAG(s0, 0);

///////////////////////////////////////////////////////////////////////////////

/// \brief Sub-match placeholder, like $1 in perl.

///

/// To create a sub-match, assign a sub-expression to the sub-match placeholder.

/// For instance, (s1= _) will match any one character and remember which

/// character was matched in the 1st sub-match. Later in the pattern, you can

/// refer back to the sub-match. For instance,  (s1= _) >> s1  will match any

/// character, and then match the same character again.

///

/// After a successful regex_match() or regex_search(), the sub-match placeholders

/// can be used to index into the match_results\<\> object to retrieve the Nth

/// sub-match.

BOOST_XPRESSIVE_GLOBAL_MARK_TAG(s1, 1);

BOOST_XPRESSIVE_GLOBAL_MARK_TAG(s2, 2);

BOOST_XPRESSIVE_GLOBAL_MARK_TAG(s3, 3);

BOOST_XPRESSIVE_GLOBAL_MARK_TAG(s4, 4);

BOOST_XPRESSIVE_GLOBAL_MARK_TAG(s5, 5);

BOOST_XPRESSIVE_GLOBAL_MARK_TAG(s6, 6);

BOOST_XPRESSIVE_GLOBAL_MARK_TAG(s7, 7);

BOOST_XPRESSIVE_GLOBAL_MARK_TAG(s8, 8);

BOOST_XPRESSIVE_GLOBAL_MARK_TAG(s9, 9);

// NOTE: For the purpose of xpressive's documentation, make icase() look like an

// ordinary function. In reality, it is a function object defined in detail/icase.hpp

// so that it can serve double-duty as regex_constants::icase, the syntax_option_type.

#ifdef BOOST_XPRESSIVE_DOXYGEN_INVOKED

///////////////////////////////////////////////////////////////////////////////

/// \brief Makes a sub-expression case-insensitive.

///

/// Use icase() to make a sub-expression case-insensitive. For instance,

/// "foo" >> icase(set['b'] >> "ar") will match "foo" exactly followed by

/// "bar" irrespective of case.

template<typename Expr> detail::unspecified icase(Expr const &expr) { return 0; }

#endif

///////////////////////////////////////////////////////////////////////////////

/// \brief Makes a literal into a regular expression.

///

/// Use as_xpr() to turn a literal into a regular expression. For instance,

/// "foo" >> "bar" will not compile because both operands to the right-shift

/// operator are const char*, and no such operator exists. Use as_xpr("foo") >> "bar"

/// instead.

///

/// You can use as_xpr() with character literals in addition to string literals.

/// For instance, as_xpr('a') will match an 'a'. You can also complement a

/// character literal, as with ~as_xpr('a'). This will match any one character

/// that is not an 'a'.

#ifdef BOOST_XPRESSIVE_DOXYGEN_INVOKED

template<typename Literal> detail::unspecified as_xpr(Literal const &literal) { return 0; }

#else

proto::functional::as_expr<> const as_xpr = {};

#endif

///////////////////////////////////////////////////////////////////////////////

/// \brief Embed a regex object by reference.

///

/// \param rex The basic_regex object to embed by reference.

template<typename BidiIter>

inline typename proto::terminal<reference_wrapper<basic_regex<BidiIter> const> >::type const

by_ref(basic_regex<BidiIter> const &rex)

{

    reference_wrapper<basic_regex<BidiIter> const> ref(rex);

    return proto::terminal<reference_wrapper<basic_regex<BidiIter> const> >::type::make(ref);

}

///////////////////////////////////////////////////////////////////////////////

/// \brief Match a range of characters.

///

/// Match any character in the range [ch_min, ch_max].

///

/// \param ch_min The lower end of the range to match.

/// \param ch_max The upper end of the range to match.

template<typename Char>

inline typename proto::terminal<detail::range_placeholder<Char> >::type const

range(Char ch_min, Char ch_max)

{

    detail::range_placeholder<Char> that = {ch_min, ch_max, false};

    return proto::terminal<detail::range_placeholder<Char> >::type::make(that);

}

///////////////////////////////////////////////////////////////////////////////

/// \brief Make a sub-expression optional. Equivalent to !as_xpr(expr).

///

/// \param expr The sub-expression to make optional.

template<typename Expr>

typename proto::result_of::make_expr<

    proto::tag::logical_not

  , proto::default_domain

  , Expr const &

>::type const

optional(Expr const &expr)

{

    return proto::make_expr<

        proto::tag::logical_not

      , proto::default_domain

    >(boost::ref(expr));

}

///////////////////////////////////////////////////////////////////////////////

/// \brief Repeat a sub-expression multiple times.

///

/// There are two forms of the repeat\<\>() function template. To match a

/// sub-expression N times, use repeat\<N\>(expr). To match a sub-expression

/// from M to N times, use repeat\<M,N\>(expr).

///

/// The repeat\<\>() function creates a greedy quantifier. To make the quantifier

/// non-greedy, apply the unary minus operator, as in -repeat\<M,N\>(expr).

///

/// \param expr The sub-expression to repeat.

template<unsigned int Min, unsigned int Max, typename Expr>

typename proto::result_of::make_expr<

    detail::generic_quant_tag<Min, Max>

  , proto::default_domain

  , Expr const &

>::type const

repeat(Expr const &expr)

{

    return proto::make_expr<

        detail::generic_quant_tag<Min, Max>

      , proto::default_domain

    >(boost::ref(expr));

}

/// \overload

///

template<unsigned int Count, typename Expr2>

typename proto::result_of::make_expr<

    detail::generic_quant_tag<Count, Count>

  , proto::default_domain

  , Expr2 const &

>::type const

repeat(Expr2 const &expr2)

{

    return proto::make_expr<

        detail::generic_quant_tag<Count, Count>

      , proto::default_domain

    >(boost::ref(expr2));

}

///////////////////////////////////////////////////////////////////////////////

/// \brief Create an independent sub-expression.

///

/// Turn off back-tracking for a sub-expression. Any branches or repeats within

/// the sub-expression will match only one way, and no other alternatives are

/// tried.

///

/// \attention keep(expr) is equivalent to the perl (?>...) extension.

///

/// \param expr The sub-expression to modify.

template<typename Expr>

typename proto::result_of::make_expr<

    detail::keeper_tag

  , proto::default_domain

  , Expr const &

>::type const

keep(Expr const &expr)

{

    return proto::make_expr<

        detail::keeper_tag

      , proto::default_domain

    >(boost::ref(expr));

}

///////////////////////////////////////////////////////////////////////////////

/// \brief Look-ahead assertion.

///

/// before(expr) succeeds if the expr sub-expression would match at the current

/// position in the sequence, but expr is not included in the match. For instance,

/// before("foo") succeeds if we are before a "foo". Look-ahead assertions can be

/// negated with the bit-compliment operator.

///

/// \attention before(expr) is equivalent to the perl (?=...) extension.

/// ~before(expr) is a negative look-ahead assertion, equivalent to the

/// perl (?!...) extension.

///

/// \param expr The sub-expression to put in the look-ahead assertion.

template<typename Expr>

typename proto::result_of::make_expr<

    detail::lookahead_tag

  , proto::default_domain

  , Expr const &

>::type const

before(Expr const &expr)

{

    return proto::make_expr<

        detail::lookahead_tag

      , proto::default_domain

    >(boost::ref(expr));

}

///////////////////////////////////////////////////////////////////////////////

/// \brief Look-behind assertion.

///

/// after(expr) succeeds if the expr sub-expression would match at the current

/// position minus N in the sequence, where N is the width of expr. expr is not included in

/// the match. For instance,  after("foo") succeeds if we are after a "foo". Look-behind

/// assertions can be negated with the bit-complement operator.

///

/// \attention after(expr) is equivalent to the perl (?<=...) extension.

/// ~after(expr) is a negative look-behind assertion, equivalent to the

/// perl (?<!...) extension.

///

/// \param expr The sub-expression to put in the look-ahead assertion.

///

/// \pre expr cannot match a variable number of characters.

template<typename Expr>

typename proto::result_of::make_expr<

    detail::lookbehind_tag

  , proto::default_domain

  , Expr const &

>::type const

after(Expr const &expr)

{

    return proto::make_expr<

        detail::lookbehind_tag

      , proto::default_domain

    >(boost::ref(expr));

}

///////////////////////////////////////////////////////////////////////////////

/// \brief Specify a regex traits or a std::locale.

///

/// imbue() instructs the regex engine to use the specified traits or locale

/// when matching the regex. The entire expression must use the same traits/locale.

/// For instance, the following specifies a locale for use with a regex:

///   std::locale loc;

///   sregex rx = imbue(loc)(+digit);

///

/// \param loc The std::locale or regex traits object.

template<typename Locale>

inline detail::modifier_op<detail::locale_modifier<Locale> > const

imbue(Locale const &loc)

{

    detail::modifier_op<detail::locale_modifier<Locale> > mod =

    {

        detail::locale_modifier<Locale>(loc)

      , regex_constants::ECMAScript

    };

    return mod;

}

proto::terminal<detail::attribute_placeholder<mpl::int_<1> > >::type const a1 = {{}};

proto::terminal<detail::attribute_placeholder<mpl::int_<2> > >::type const a2 = {{}};

proto::terminal<detail::attribute_placeholder<mpl::int_<3> > >::type const a3 = {{}};

proto::terminal<detail::attribute_placeholder<mpl::int_<4> > >::type const a4 = {{}};

proto::terminal<detail::attribute_placeholder<mpl::int_<5> > >::type const a5 = {{}};

proto::terminal<detail::attribute_placeholder<mpl::int_<6> > >::type const a6 = {{}};

proto::terminal<detail::attribute_placeholder<mpl::int_<7> > >::type const a7 = {{}};

proto::terminal<detail::attribute_placeholder<mpl::int_<8> > >::type const a8 = {{}};

proto::terminal<detail::attribute_placeholder<mpl::int_<9> > >::type const a9 = {{}};

///////////////////////////////////////////////////////////////////////////////

/// \brief Specify which characters to skip when matching a regex.

///

/// <tt>skip()</tt> instructs the regex engine to skip certain characters when matching

/// a regex. It is most useful for writing regexes that ignore whitespace.

/// For instance, the following specifies a regex that skips whitespace and

/// punctuation:

///

/// \code

/// // A sentence is one or more words separated by whitespace

/// // and punctuation.

/// sregex word = +alpha;

/// sregex sentence = skip(set[_s | punct])( +word );

/// \endcode

///

/// The way it works in the above example is to insert

/// <tt>keep(*set[_s | punct])</tt> before each primitive within the regex.

/// A "primitive" includes terminals like strings, character sets and nested

/// regexes. A final <tt>*set[_s | punct]</tt> is added to the end of the

/// regex. The regex <tt>sentence</tt> specified above is equivalent to

/// the following:

///

/// \code

/// sregex sentence = +( keep(*set[_s | punct]) >> word )

///                        >> *set[_s | punct];

/// \endcode

///

/// \attention Skipping does not affect how nested regexes are handled because

/// they are treated atomically. String literals are also treated

/// atomically; that is, no skipping is done within a string literal. So

/// <tt>skip(_s)("this that")</tt> is not the same as

/// <tt>skip(_s)("this" >> as_xpr("that"))</tt>. The first will only match

/// when there is only one space between "this" and "that". The second will

/// skip any and all whitespace between "this" and "that".

///

/// \param skip A regex that specifies which characters to skip.

template<typename Skip>

detail::skip_directive<Skip> skip(Skip const &skip)

{

    return detail::skip_directive<Skip>(skip);

}

namespace detail

{

    inline void ignore_unused_regex_primitives()

    {

        detail::ignore_unused(repeat_max);

        detail::ignore_unused(inf);

        detail::ignore_unused(epsilon);

        detail::ignore_unused(nil);

        detail::ignore_unused(alnum);

        detail::ignore_unused(bos);

        detail::ignore_unused(eos);

        detail::ignore_unused(bol);

        detail::ignore_unused(eol);

        detail::ignore_unused(bow);

        detail::ignore_unused(eow);

        detail::ignore_unused(_b);

        detail::ignore_unused(_w);

        detail::ignore_unused(_d);

        detail::ignore_unused(_s);

        detail::ignore_unused(_n);

        detail::ignore_unused(_ln);

        detail::ignore_unused(_);

        detail::ignore_unused(self);

        detail::ignore_unused(set);

        detail::ignore_unused(s0);

        detail::ignore_unused(s1);

        detail::ignore_unused(s2);

        detail::ignore_unused(s3);

        detail::ignore_unused(s4);

        detail::ignore_unused(s5);

        detail::ignore_unused(s6);

        detail::ignore_unused(s7);

        detail::ignore_unused(s8);

        detail::ignore_unused(s9);

        detail::ignore_unused(a1);

        detail::ignore_unused(a2);

        detail::ignore_unused(a3);

        detail::ignore_unused(a4);

        detail::ignore_unused(a5);

        detail::ignore_unused(a6);

        detail::ignore_unused(a7);

        detail::ignore_unused(a8);

        detail::ignore_unused(a9);

        detail::ignore_unused(as_xpr);

    }

}

}} // namespace boost::xpressive

#endif