/rust/registry/src/index.crates.io-1949cf8c6b5b557f/regex-syntax-0.6.29/src/ast/print.rs

Source
/*!
This module provides a regular expression printer for `Ast`.
*/

use std::fmt;

use crate::ast::visitor::{self, Visitor};
use crate::ast::{self, Ast};

/// A builder for constructing a printer.
///
/// Note that since a printer doesn't have any configuration knobs, this type
/// remains unexported.
#[derive(Clone, Debug)]
struct PrinterBuilder {
    _priv: (),
}

impl Default for PrinterBuilder {
    fn default() -> PrinterBuilder {
        PrinterBuilder::new()
    }
}

impl PrinterBuilder {
    fn new() -> PrinterBuilder {
        PrinterBuilder { _priv: () }
    }

    fn build(&self) -> Printer {
        Printer { _priv: () }
    }
}

/// A printer for a regular expression abstract syntax tree.
///
/// A printer converts an abstract syntax tree (AST) to a regular expression
/// pattern string. This particular printer uses constant stack space and heap
/// space proportional to the size of the AST.
///
/// This printer will not necessarily preserve the original formatting of the
/// regular expression pattern string. For example, all whitespace and comments
/// are ignored.
#[derive(Debug)]
pub struct Printer {
    _priv: (),
}

impl Printer {
    /// Create a new printer.
    pub fn new() -> Printer {
        PrinterBuilder::new().build()
    }

    /// Print the given `Ast` to the given writer. The writer must implement
    /// `fmt::Write`. Typical implementations of `fmt::Write` that can be used
    /// here are a `fmt::Formatter` (which is available in `fmt::Display`
    /// implementations) or a `&mut String`.
    pub fn print<W: fmt::Write>(&mut self, ast: &Ast, wtr: W) -> fmt::Result {
        visitor::visit(ast, Writer { wtr })
    }
}

#[derive(Debug)]
struct Writer<W> {
    wtr: W,
}

impl<W: fmt::Write> Visitor for Writer<W> {
    type Output = ();
    type Err = fmt::Error;

    fn finish(self) -> fmt::Result {
        Ok(())
    }

    fn visit_pre(&mut self, ast: &Ast) -> fmt::Result {
        match *ast {
            Ast::Group(ref x) => self.fmt_group_pre(x),
            Ast::Class(ast::Class::Bracketed(ref x)) => {
                self.fmt_class_bracketed_pre(x)
            }
            _ => Ok(()),
        }
    }

    fn visit_post(&mut self, ast: &Ast) -> fmt::Result {
        use crate::ast::Class;

        match *ast {
            Ast::Empty(_) => Ok(()),
            Ast::Flags(ref x) => self.fmt_set_flags(x),
            Ast::Literal(ref x) => self.fmt_literal(x),
            Ast::Dot(_) => self.wtr.write_str("."),
            Ast::Assertion(ref x) => self.fmt_assertion(x),
            Ast::Class(Class::Perl(ref x)) => self.fmt_class_perl(x),
            Ast::Class(Class::Unicode(ref x)) => self.fmt_class_unicode(x),
            Ast::Class(Class::Bracketed(ref x)) => {
                self.fmt_class_bracketed_post(x)
            }
            Ast::Repetition(ref x) => self.fmt_repetition(x),
            Ast::Group(ref x) => self.fmt_group_post(x),
            Ast::Alternation(_) => Ok(()),
            Ast::Concat(_) => Ok(()),
        }
    }

    fn visit_alternation_in(&mut self) -> fmt::Result {
        self.wtr.write_str("|")
    }

    fn visit_class_set_item_pre(
        &mut self,
        ast: &ast::ClassSetItem,
    ) -> Result<(), Self::Err> {
        match *ast {
            ast::ClassSetItem::Bracketed(ref x) => {
                self.fmt_class_bracketed_pre(x)
            }
            _ => Ok(()),
        }
    }

    fn visit_class_set_item_post(
        &mut self,
        ast: &ast::ClassSetItem,
    ) -> Result<(), Self::Err> {
        use crate::ast::ClassSetItem::*;

        match *ast {
            Empty(_) => Ok(()),
            Literal(ref x) => self.fmt_literal(x),
            Range(ref x) => {
                self.fmt_literal(&x.start)?;
                self.wtr.write_str("-")?;
                self.fmt_literal(&x.end)?;
                Ok(())
            }
            Ascii(ref x) => self.fmt_class_ascii(x),
            Unicode(ref x) => self.fmt_class_unicode(x),
            Perl(ref x) => self.fmt_class_perl(x),
            Bracketed(ref x) => self.fmt_class_bracketed_post(x),
            Union(_) => Ok(()),
        }
    }

    fn visit_class_set_binary_op_in(
        &mut self,
        ast: &ast::ClassSetBinaryOp,
    ) -> Result<(), Self::Err> {
        self.fmt_class_set_binary_op_kind(&ast.kind)
    }
}

impl<W: fmt::Write> Writer<W> {
    fn fmt_group_pre(&mut self, ast: &ast::Group) -> fmt::Result {
        use crate::ast::GroupKind::*;
        match ast.kind {
            CaptureIndex(_) => self.wtr.write_str("("),
            CaptureName(ref x) => {
                self.wtr.write_str("(?P<")?;
                self.wtr.write_str(&x.name)?;
                self.wtr.write_str(">")?;
                Ok(())
            }
            NonCapturing(ref flags) => {
                self.wtr.write_str("(?")?;
                self.fmt_flags(flags)?;
                self.wtr.write_str(":")?;
                Ok(())
            }
        }
    }

    fn fmt_group_post(&mut self, _ast: &ast::Group) -> fmt::Result {
        self.wtr.write_str(")")
    }

    fn fmt_repetition(&mut self, ast: &ast::Repetition) -> fmt::Result {
        use crate::ast::RepetitionKind::*;
        match ast.op.kind {
            ZeroOrOne if ast.greedy => self.wtr.write_str("?"),
            ZeroOrOne => self.wtr.write_str("??"),
            ZeroOrMore if ast.greedy => self.wtr.write_str("*"),
            ZeroOrMore => self.wtr.write_str("*?"),
            OneOrMore if ast.greedy => self.wtr.write_str("+"),
            OneOrMore => self.wtr.write_str("+?"),
            Range(ref x) => {
                self.fmt_repetition_range(x)?;
                if !ast.greedy {
                    self.wtr.write_str("?")?;
                }
                Ok(())
            }
        }
    }

    fn fmt_repetition_range(
        &mut self,
        ast: &ast::RepetitionRange,
    ) -> fmt::Result {
        use crate::ast::RepetitionRange::*;
        match *ast {
            Exactly(x) => write!(self.wtr, "{{{}}}", x),
            AtLeast(x) => write!(self.wtr, "{{{},}}", x),
            Bounded(x, y) => write!(self.wtr, "{{{},{}}}", x, y),
        }
    }

    fn fmt_literal(&mut self, ast: &ast::Literal) -> fmt::Result {
        use crate::ast::LiteralKind::*;

        match ast.kind {
            Verbatim => self.wtr.write_char(ast.c),
            Punctuation => write!(self.wtr, r"\{}", ast.c),
            Octal => write!(self.wtr, r"\{:o}", ast.c as u32),
            HexFixed(ast::HexLiteralKind::X) => {
                write!(self.wtr, r"\x{:02X}", ast.c as u32)
            }
            HexFixed(ast::HexLiteralKind::UnicodeShort) => {
                write!(self.wtr, r"\u{:04X}", ast.c as u32)
            }
            HexFixed(ast::HexLiteralKind::UnicodeLong) => {
                write!(self.wtr, r"\U{:08X}", ast.c as u32)
            }
            HexBrace(ast::HexLiteralKind::X) => {
                write!(self.wtr, r"\x{{{:X}}}", ast.c as u32)
            }
            HexBrace(ast::HexLiteralKind::UnicodeShort) => {
                write!(self.wtr, r"\u{{{:X}}}", ast.c as u32)
            }
            HexBrace(ast::HexLiteralKind::UnicodeLong) => {
                write!(self.wtr, r"\U{{{:X}}}", ast.c as u32)
            }
            Special(ast::SpecialLiteralKind::Bell) => {
                self.wtr.write_str(r"\a")
            }
            Special(ast::SpecialLiteralKind::FormFeed) => {
                self.wtr.write_str(r"\f")
            }
            Special(ast::SpecialLiteralKind::Tab) => self.wtr.write_str(r"\t"),
            Special(ast::SpecialLiteralKind::LineFeed) => {
                self.wtr.write_str(r"\n")
            }
            Special(ast::SpecialLiteralKind::CarriageReturn) => {
                self.wtr.write_str(r"\r")
            }
            Special(ast::SpecialLiteralKind::VerticalTab) => {
                self.wtr.write_str(r"\v")
            }
            Special(ast::SpecialLiteralKind::Space) => {
                self.wtr.write_str(r"\ ")
            }
        }
    }

    fn fmt_assertion(&mut self, ast: &ast::Assertion) -> fmt::Result {
        use crate::ast::AssertionKind::*;
        match ast.kind {
            StartLine => self.wtr.write_str("^"),
            EndLine => self.wtr.write_str("$"),
            StartText => self.wtr.write_str(r"\A"),
            EndText => self.wtr.write_str(r"\z"),
            WordBoundary => self.wtr.write_str(r"\b"),
            NotWordBoundary => self.wtr.write_str(r"\B"),
        }
    }

    fn fmt_set_flags(&mut self, ast: &ast::SetFlags) -> fmt::Result {
        self.wtr.write_str("(?")?;
        self.fmt_flags(&ast.flags)?;
        self.wtr.write_str(")")?;
        Ok(())
    }

    fn fmt_flags(&mut self, ast: &ast::Flags) -> fmt::Result {
        use crate::ast::{Flag, FlagsItemKind};

        for item in &ast.items {
            match item.kind {
                FlagsItemKind::Negation => self.wtr.write_str("-"),
                FlagsItemKind::Flag(ref flag) => match *flag {
                    Flag::CaseInsensitive => self.wtr.write_str("i"),
                    Flag::MultiLine => self.wtr.write_str("m"),
                    Flag::DotMatchesNewLine => self.wtr.write_str("s"),
                    Flag::SwapGreed => self.wtr.write_str("U"),
                    Flag::Unicode => self.wtr.write_str("u"),
                    Flag::IgnoreWhitespace => self.wtr.write_str("x"),
                },
            }?;
        }
        Ok(())
    }

    fn fmt_class_bracketed_pre(
        &mut self,
        ast: &ast::ClassBracketed,
    ) -> fmt::Result {
        if ast.negated {
            self.wtr.write_str("[^")
        } else {
            self.wtr.write_str("[")
        }
    }

    fn fmt_class_bracketed_post(
        &mut self,
        _ast: &ast::ClassBracketed,
    ) -> fmt::Result {
        self.wtr.write_str("]")
    }

    fn fmt_class_set_binary_op_kind(
        &mut self,
        ast: &ast::ClassSetBinaryOpKind,
    ) -> fmt::Result {
        use crate::ast::ClassSetBinaryOpKind::*;
        match *ast {
            Intersection => self.wtr.write_str("&&"),
            Difference => self.wtr.write_str("--"),
            SymmetricDifference => self.wtr.write_str("~~"),
        }
    }

    fn fmt_class_perl(&mut self, ast: &ast::ClassPerl) -> fmt::Result {
        use crate::ast::ClassPerlKind::*;
        match ast.kind {
            Digit if ast.negated => self.wtr.write_str(r"\D"),
            Digit => self.wtr.write_str(r"\d"),
            Space if ast.negated => self.wtr.write_str(r"\S"),
            Space => self.wtr.write_str(r"\s"),
            Word if ast.negated => self.wtr.write_str(r"\W"),
            Word => self.wtr.write_str(r"\w"),
        }
    }

    fn fmt_class_ascii(&mut self, ast: &ast::ClassAscii) -> fmt::Result {
        use crate::ast::ClassAsciiKind::*;
        match ast.kind {
            Alnum if ast.negated => self.wtr.write_str("[:^alnum:]"),
            Alnum => self.wtr.write_str("[:alnum:]"),
            Alpha if ast.negated => self.wtr.write_str("[:^alpha:]"),
            Alpha => self.wtr.write_str("[:alpha:]"),
            Ascii if ast.negated => self.wtr.write_str("[:^ascii:]"),
            Ascii => self.wtr.write_str("[:ascii:]"),
            Blank if ast.negated => self.wtr.write_str("[:^blank:]"),
            Blank => self.wtr.write_str("[:blank:]"),
            Cntrl if ast.negated => self.wtr.write_str("[:^cntrl:]"),
            Cntrl => self.wtr.write_str("[:cntrl:]"),
            Digit if ast.negated => self.wtr.write_str("[:^digit:]"),
            Digit => self.wtr.write_str("[:digit:]"),
            Graph if ast.negated => self.wtr.write_str("[:^graph:]"),
            Graph => self.wtr.write_str("[:graph:]"),
            Lower if ast.negated => self.wtr.write_str("[:^lower:]"),
            Lower => self.wtr.write_str("[:lower:]"),
            Print if ast.negated => self.wtr.write_str("[:^print:]"),
            Print => self.wtr.write_str("[:print:]"),
            Punct if ast.negated => self.wtr.write_str("[:^punct:]"),
            Punct => self.wtr.write_str("[:punct:]"),
            Space if ast.negated => self.wtr.write_str("[:^space:]"),
            Space => self.wtr.write_str("[:space:]"),
            Upper if ast.negated => self.wtr.write_str("[:^upper:]"),
            Upper => self.wtr.write_str("[:upper:]"),
            Word if ast.negated => self.wtr.write_str("[:^word:]"),
            Word => self.wtr.write_str("[:word:]"),
            Xdigit if ast.negated => self.wtr.write_str("[:^xdigit:]"),
            Xdigit => self.wtr.write_str("[:xdigit:]"),
        }
    }

    fn fmt_class_unicode(&mut self, ast: &ast::ClassUnicode) -> fmt::Result {
        use crate::ast::ClassUnicodeKind::*;
        use crate::ast::ClassUnicodeOpKind::*;

        if ast.negated {
            self.wtr.write_str(r"\P")?;
        } else {
            self.wtr.write_str(r"\p")?;
        }
        match ast.kind {
            OneLetter(c) => self.wtr.write_char(c),
            Named(ref x) => write!(self.wtr, "{{{}}}", x),
            NamedValue { op: Equal, ref name, ref value } => {
                write!(self.wtr, "{{{}={}}}", name, value)
            }
            NamedValue { op: Colon, ref name, ref value } => {
                write!(self.wtr, "{{{}:{}}}", name, value)
            }
            NamedValue { op: NotEqual, ref name, ref value } => {
                write!(self.wtr, "{{{}!={}}}", name, value)
            }
        }
    }
}

#[cfg(test)]
mod tests {
    use super::Printer;
    use crate::ast::parse::ParserBuilder;

    fn roundtrip(given: &str) {
        roundtrip_with(|b| b, given);
    }

    fn roundtrip_with<F>(mut f: F, given: &str)
    where
        F: FnMut(&mut ParserBuilder) -> &mut ParserBuilder,
    {
        let mut builder = ParserBuilder::new();
        f(&mut builder);
        let ast = builder.build().parse(given).unwrap();

        let mut printer = Printer::new();
        let mut dst = String::new();
        printer.print(&ast, &mut dst).unwrap();
        assert_eq!(given, dst);
    }

    #[test]
    fn print_literal() {
        roundtrip("a");
        roundtrip(r"\[");
        roundtrip_with(|b| b.octal(true), r"\141");
        roundtrip(r"\x61");
        roundtrip(r"\x7F");
        roundtrip(r"\u0061");
        roundtrip(r"\U00000061");
        roundtrip(r"\x{61}");
        roundtrip(r"\x{7F}");
        roundtrip(r"\u{61}");
        roundtrip(r"\U{61}");

        roundtrip(r"\a");
        roundtrip(r"\f");
        roundtrip(r"\t");
        roundtrip(r"\n");
        roundtrip(r"\r");
        roundtrip(r"\v");
        roundtrip(r"(?x)\ ");
    }

    #[test]
    fn print_dot() {
        roundtrip(".");
    }

    #[test]
    fn print_concat() {
        roundtrip("ab");
        roundtrip("abcde");
        roundtrip("a(bcd)ef");
    }

    #[test]
    fn print_alternation() {
        roundtrip("a|b");
        roundtrip("a|b|c|d|e");
        roundtrip("|a|b|c|d|e");
        roundtrip("|a|b|c|d|e|");
        roundtrip("a(b|c|d)|e|f");
    }

    #[test]
    fn print_assertion() {
        roundtrip(r"^");
        roundtrip(r"$");
        roundtrip(r"\A");
        roundtrip(r"\z");
        roundtrip(r"\b");
        roundtrip(r"\B");
    }

    #[test]
    fn print_repetition() {
        roundtrip("a?");
        roundtrip("a??");
        roundtrip("a*");
        roundtrip("a*?");
        roundtrip("a+");
        roundtrip("a+?");
        roundtrip("a{5}");
        roundtrip("a{5}?");
        roundtrip("a{5,}");
        roundtrip("a{5,}?");
        roundtrip("a{5,10}");
        roundtrip("a{5,10}?");
    }

    #[test]
    fn print_flags() {
        roundtrip("(?i)");
        roundtrip("(?-i)");
        roundtrip("(?s-i)");
        roundtrip("(?-si)");
        roundtrip("(?siUmux)");
    }

    #[test]
    fn print_group() {
        roundtrip("(?i:a)");
        roundtrip("(?P<foo>a)");
        roundtrip("(a)");
    }

    #[test]
    fn print_class() {
        roundtrip(r"[abc]");
        roundtrip(r"[a-z]");
        roundtrip(r"[^a-z]");
        roundtrip(r"[a-z0-9]");
        roundtrip(r"[-a-z0-9]");
        roundtrip(r"[-a-z0-9]");
        roundtrip(r"[a-z0-9---]");
        roundtrip(r"[a-z&&m-n]");
        roundtrip(r"[[a-z&&m-n]]");
        roundtrip(r"[a-z--m-n]");
        roundtrip(r"[a-z~~m-n]");
        roundtrip(r"[a-z[0-9]]");
        roundtrip(r"[a-z[^0-9]]");

        roundtrip(r"\d");
        roundtrip(r"\D");
        roundtrip(r"\s");
        roundtrip(r"\S");
        roundtrip(r"\w");
        roundtrip(r"\W");

        roundtrip(r"[[:alnum:]]");
        roundtrip(r"[[:^alnum:]]");
        roundtrip(r"[[:alpha:]]");
        roundtrip(r"[[:^alpha:]]");
        roundtrip(r"[[:ascii:]]");
        roundtrip(r"[[:^ascii:]]");
        roundtrip(r"[[:blank:]]");
        roundtrip(r"[[:^blank:]]");
        roundtrip(r"[[:cntrl:]]");
        roundtrip(r"[[:^cntrl:]]");
        roundtrip(r"[[:digit:]]");
        roundtrip(r"[[:^digit:]]");
        roundtrip(r"[[:graph:]]");
        roundtrip(r"[[:^graph:]]");
        roundtrip(r"[[:lower:]]");
        roundtrip(r"[[:^lower:]]");
        roundtrip(r"[[:print:]]");
        roundtrip(r"[[:^print:]]");
        roundtrip(r"[[:punct:]]");
        roundtrip(r"[[:^punct:]]");
        roundtrip(r"[[:space:]]");
        roundtrip(r"[[:^space:]]");
        roundtrip(r"[[:upper:]]");
        roundtrip(r"[[:^upper:]]");
        roundtrip(r"[[:word:]]");
        roundtrip(r"[[:^word:]]");
        roundtrip(r"[[:xdigit:]]");
        roundtrip(r"[[:^xdigit:]]");

        roundtrip(r"\pL");
        roundtrip(r"\PL");
        roundtrip(r"\p{L}");
        roundtrip(r"\P{L}");
        roundtrip(r"\p{X=Y}");
        roundtrip(r"\P{X=Y}");
        roundtrip(r"\p{X:Y}");
        roundtrip(r"\P{X:Y}");
        roundtrip(r"\p{X!=Y}");
        roundtrip(r"\P{X!=Y}");
    }
}

Coverage Report

Created: 2025-12-28 06:31

Line	Count	Source
1		/*!
2		This module provides a regular expression printer for `Ast`.
3		*/
4
5		use std::fmt;
6
7		use crate::ast::visitor::{self, Visitor};
8		use crate::ast::{self, Ast};
9
10		/// A builder for constructing a printer.
11		///
12		/// Note that since a printer doesn't have any configuration knobs, this type
13		/// remains unexported.
14		#[derive(Clone, Debug)]
15		struct PrinterBuilder {
16		_priv: (),
17		}
18
19		impl Default for PrinterBuilder {
20	0	fn default() -> PrinterBuilder {
21	0	PrinterBuilder::new()
22	0	}
23		}
24
25		impl PrinterBuilder {
26	0	fn new() -> PrinterBuilder {
27	0	PrinterBuilder { _priv: () }
28	0	}
29
30	0	fn build(&self) -> Printer {
31	0	Printer { _priv: () }
32	0	}
33		}
34
35		/// A printer for a regular expression abstract syntax tree.
36		///
37		/// A printer converts an abstract syntax tree (AST) to a regular expression
38		/// pattern string. This particular printer uses constant stack space and heap
39		/// space proportional to the size of the AST.
40		///
41		/// This printer will not necessarily preserve the original formatting of the
42		/// regular expression pattern string. For example, all whitespace and comments
43		/// are ignored.
44		#[derive(Debug)]
45		pub struct Printer {
46		_priv: (),
47		}
48
49		impl Printer {
50		/// Create a new printer.
51	0	pub fn new() -> Printer {
52	0	PrinterBuilder::new().build()
53	0	}
54
55		/// Print the given `Ast` to the given writer. The writer must implement
56		/// `fmt::Write`. Typical implementations of `fmt::Write` that can be used
57		/// here are a `fmt::Formatter` (which is available in `fmt::Display`
58		/// implementations) or a `&mut String`.
59	0	pub fn print<W: fmt::Write>(&mut self, ast: &Ast, wtr: W) -> fmt::Result {
60	0	visitor::visit(ast, Writer { wtr })
61	0	}
62		}
63
64		#[derive(Debug)]
65		struct Writer<W> {
66		wtr: W,
67		}
68
69		impl<W: fmt::Write> Visitor for Writer<W> {
70		type Output = ();
71		type Err = fmt::Error;
72
73	0	fn finish(self) -> fmt::Result {
74	0	Ok(())
75	0	}
76
77	0	fn visit_pre(&mut self, ast: &Ast) -> fmt::Result {
78	0	match *ast {
79	0	Ast::Group(ref x) => self.fmt_group_pre(x),
80	0	Ast::Class(ast::Class::Bracketed(ref x)) => {
81	0	self.fmt_class_bracketed_pre(x)
82		}
83	0	_ => Ok(()),
84		}
85	0	}
86
87	0	fn visit_post(&mut self, ast: &Ast) -> fmt::Result {
88		use crate::ast::Class;
89
90	0	match *ast {
91	0	Ast::Empty(_) => Ok(()),
92	0	Ast::Flags(ref x) => self.fmt_set_flags(x),
93	0	Ast::Literal(ref x) => self.fmt_literal(x),
94	0	Ast::Dot(_) => self.wtr.write_str("."),
95	0	Ast::Assertion(ref x) => self.fmt_assertion(x),
96	0	Ast::Class(Class::Perl(ref x)) => self.fmt_class_perl(x),
97	0	Ast::Class(Class::Unicode(ref x)) => self.fmt_class_unicode(x),
98	0	Ast::Class(Class::Bracketed(ref x)) => {
99	0	self.fmt_class_bracketed_post(x)
100		}
101	0	Ast::Repetition(ref x) => self.fmt_repetition(x),
102	0	Ast::Group(ref x) => self.fmt_group_post(x),
103	0	Ast::Alternation(_) => Ok(()),
104	0	Ast::Concat(_) => Ok(()),
105		}
106	0	}
107
108	0	fn visit_alternation_in(&mut self) -> fmt::Result {
109	0	self.wtr.write_str("\|")
110	0	}
111
112	0	fn visit_class_set_item_pre(
113	0	&mut self,
114	0	ast: &ast::ClassSetItem,
115	0	) -> Result<(), Self::Err> {
116	0	match *ast {
117	0	ast::ClassSetItem::Bracketed(ref x) => {
118	0	self.fmt_class_bracketed_pre(x)
119		}
120	0	_ => Ok(()),
121		}
122	0	}
123
124	0	fn visit_class_set_item_post(
125	0	&mut self,
126	0	ast: &ast::ClassSetItem,
127	0	) -> Result<(), Self::Err> {
128		use crate::ast::ClassSetItem::*;
129
130	0	match *ast {
131	0	Empty(_) => Ok(()),
132	0	Literal(ref x) => self.fmt_literal(x),
133	0	Range(ref x) => {
134	0	self.fmt_literal(&x.start)?;
135	0	self.wtr.write_str("-")?;
136	0	self.fmt_literal(&x.end)?;
137	0	Ok(())
138		}
139	0	Ascii(ref x) => self.fmt_class_ascii(x),
140	0	Unicode(ref x) => self.fmt_class_unicode(x),
141	0	Perl(ref x) => self.fmt_class_perl(x),
142	0	Bracketed(ref x) => self.fmt_class_bracketed_post(x),
143	0	Union(_) => Ok(()),
144		}
145	0	}
146
147	0	fn visit_class_set_binary_op_in(
148	0	&mut self,
149	0	ast: &ast::ClassSetBinaryOp,
150	0	) -> Result<(), Self::Err> {
151	0	self.fmt_class_set_binary_op_kind(&ast.kind)
152	0	}
153		}
154
155		impl<W: fmt::Write> Writer<W> {
156	0	fn fmt_group_pre(&mut self, ast: &ast::Group) -> fmt::Result {
157		use crate::ast::GroupKind::*;
158	0	match ast.kind {
159	0	CaptureIndex(_) => self.wtr.write_str("("),
160	0	CaptureName(ref x) => {
161	0	self.wtr.write_str("(?P<")?;
162	0	self.wtr.write_str(&x.name)?;
163	0	self.wtr.write_str(">")?;
164	0	Ok(())
165		}
166	0	NonCapturing(ref flags) => {
167	0	self.wtr.write_str("(?")?;
168	0	self.fmt_flags(flags)?;
169	0	self.wtr.write_str(":")?;
170	0	Ok(())
171		}
172		}
173	0	}
174
175	0	fn fmt_group_post(&mut self, _ast: &ast::Group) -> fmt::Result {
176	0	self.wtr.write_str(")")
177	0	}
178
179	0	fn fmt_repetition(&mut self, ast: &ast::Repetition) -> fmt::Result {
180		use crate::ast::RepetitionKind::*;
181	0	match ast.op.kind {
182	0	ZeroOrOne if ast.greedy => self.wtr.write_str("?"),
183	0	ZeroOrOne => self.wtr.write_str("??"),
184	0	ZeroOrMore if ast.greedy => self.wtr.write_str("*"),
185	0	ZeroOrMore => self.wtr.write_str("*?"),
186	0	OneOrMore if ast.greedy => self.wtr.write_str("+"),
187	0	OneOrMore => self.wtr.write_str("+?"),
188	0	Range(ref x) => {
189	0	self.fmt_repetition_range(x)?;
190	0	if !ast.greedy {
191	0	self.wtr.write_str("?")?;
192	0	}
193	0	Ok(())
194		}
195		}
196	0	}
197
198	0	fn fmt_repetition_range(
199	0	&mut self,
200	0	ast: &ast::RepetitionRange,
201	0	) -> fmt::Result {
202		use crate::ast::RepetitionRange::*;
203	0	match *ast {
204	0	Exactly(x) => write!(self.wtr, "{{{}}}", x),
205	0	AtLeast(x) => write!(self.wtr, "{{{},}}", x),
206	0	Bounded(x, y) => write!(self.wtr, "{{{},{}}}", x, y),
207		}
208	0	}
209
210	0	fn fmt_literal(&mut self, ast: &ast::Literal) -> fmt::Result {
211		use crate::ast::LiteralKind::*;
212
213	0	match ast.kind {
214	0	Verbatim => self.wtr.write_char(ast.c),
215	0	Punctuation => write!(self.wtr, r"\{}", ast.c),
216	0	Octal => write!(self.wtr, r"\{:o}", ast.c as u32),
217		HexFixed(ast::HexLiteralKind::X) => {
218	0	write!(self.wtr, r"\x{:02X}", ast.c as u32)
219		}
220		HexFixed(ast::HexLiteralKind::UnicodeShort) => {
221	0	write!(self.wtr, r"\u{:04X}", ast.c as u32)
222		}
223		HexFixed(ast::HexLiteralKind::UnicodeLong) => {
224	0	write!(self.wtr, r"\U{:08X}", ast.c as u32)
225		}
226		HexBrace(ast::HexLiteralKind::X) => {
227	0	write!(self.wtr, r"\x{{{:X}}}", ast.c as u32)
228		}
229		HexBrace(ast::HexLiteralKind::UnicodeShort) => {
230	0	write!(self.wtr, r"\u{{{:X}}}", ast.c as u32)
231		}
232		HexBrace(ast::HexLiteralKind::UnicodeLong) => {
233	0	write!(self.wtr, r"\U{{{:X}}}", ast.c as u32)
234		}
235		Special(ast::SpecialLiteralKind::Bell) => {
236	0	self.wtr.write_str(r"\a")
237		}
238		Special(ast::SpecialLiteralKind::FormFeed) => {
239	0	self.wtr.write_str(r"\f")
240		}
241	0	Special(ast::SpecialLiteralKind::Tab) => self.wtr.write_str(r"\t"),
242		Special(ast::SpecialLiteralKind::LineFeed) => {
243	0	self.wtr.write_str(r"\n")
244		}
245		Special(ast::SpecialLiteralKind::CarriageReturn) => {
246	0	self.wtr.write_str(r"\r")
247		}
248		Special(ast::SpecialLiteralKind::VerticalTab) => {
249	0	self.wtr.write_str(r"\v")
250		}
251		Special(ast::SpecialLiteralKind::Space) => {
252	0	self.wtr.write_str(r"\ ")
253		}
254		}
255	0	}
256
257	0	fn fmt_assertion(&mut self, ast: &ast::Assertion) -> fmt::Result {
258		use crate::ast::AssertionKind::*;
259	0	match ast.kind {
260	0	StartLine => self.wtr.write_str("^"),
261	0	EndLine => self.wtr.write_str("$"),
262	0	StartText => self.wtr.write_str(r"\A"),
263	0	EndText => self.wtr.write_str(r"\z"),
264	0	WordBoundary => self.wtr.write_str(r"\b"),
265	0	NotWordBoundary => self.wtr.write_str(r"\B"),
266		}
267	0	}
268
269	0	fn fmt_set_flags(&mut self, ast: &ast::SetFlags) -> fmt::Result {
270	0	self.wtr.write_str("(?")?;
271	0	self.fmt_flags(&ast.flags)?;
272	0	self.wtr.write_str(")")?;
273	0	Ok(())
274	0	}
275
276	0	fn fmt_flags(&mut self, ast: &ast::Flags) -> fmt::Result {
277		use crate::ast::{Flag, FlagsItemKind};
278
279	0	for item in &ast.items {
280	0	match item.kind {
281	0	FlagsItemKind::Negation => self.wtr.write_str("-"),
282	0	FlagsItemKind::Flag(ref flag) => match *flag {
283	0	Flag::CaseInsensitive => self.wtr.write_str("i"),
284	0	Flag::MultiLine => self.wtr.write_str("m"),
285	0	Flag::DotMatchesNewLine => self.wtr.write_str("s"),
286	0	Flag::SwapGreed => self.wtr.write_str("U"),
287	0	Flag::Unicode => self.wtr.write_str("u"),
288	0	Flag::IgnoreWhitespace => self.wtr.write_str("x"),
289		},
290	0	}?;
291		}
292	0	Ok(())
293	0	}
294
295	0	fn fmt_class_bracketed_pre(
296	0	&mut self,
297	0	ast: &ast::ClassBracketed,
298	0	) -> fmt::Result {
299	0	if ast.negated {
300	0	self.wtr.write_str("[^")
301		} else {
302	0	self.wtr.write_str("[")
303		}
304	0	}
305
306	0	fn fmt_class_bracketed_post(
307	0	&mut self,
308	0	_ast: &ast::ClassBracketed,
309	0	) -> fmt::Result {
310	0	self.wtr.write_str("]")
311	0	}
312
313	0	fn fmt_class_set_binary_op_kind(
314	0	&mut self,
315	0	ast: &ast::ClassSetBinaryOpKind,
316	0	) -> fmt::Result {
317		use crate::ast::ClassSetBinaryOpKind::*;
318	0	match *ast {
319	0	Intersection => self.wtr.write_str("&&"),
320	0	Difference => self.wtr.write_str("--"),
321	0	SymmetricDifference => self.wtr.write_str("~~"),
322		}
323	0	}
324
325	0	fn fmt_class_perl(&mut self, ast: &ast::ClassPerl) -> fmt::Result {
326		use crate::ast::ClassPerlKind::*;
327	0	match ast.kind {
328	0	Digit if ast.negated => self.wtr.write_str(r"\D"),
329	0	Digit => self.wtr.write_str(r"\d"),
330	0	Space if ast.negated => self.wtr.write_str(r"\S"),
331	0	Space => self.wtr.write_str(r"\s"),
332	0	Word if ast.negated => self.wtr.write_str(r"\W"),
333	0	Word => self.wtr.write_str(r"\w"),
334		}
335	0	}
336
337	0	fn fmt_class_ascii(&mut self, ast: &ast::ClassAscii) -> fmt::Result {
338		use crate::ast::ClassAsciiKind::*;
339	0	match ast.kind {
340	0	Alnum if ast.negated => self.wtr.write_str("[:^alnum:]"),
341	0	Alnum => self.wtr.write_str("[:alnum:]"),
342	0	Alpha if ast.negated => self.wtr.write_str("[:^alpha:]"),
343	0	Alpha => self.wtr.write_str("[:alpha:]"),
344	0	Ascii if ast.negated => self.wtr.write_str("[:^ascii:]"),
345	0	Ascii => self.wtr.write_str("[:ascii:]"),
346	0	Blank if ast.negated => self.wtr.write_str("[:^blank:]"),
347	0	Blank => self.wtr.write_str("[:blank:]"),
348	0	Cntrl if ast.negated => self.wtr.write_str("[:^cntrl:]"),
349	0	Cntrl => self.wtr.write_str("[:cntrl:]"),
350	0	Digit if ast.negated => self.wtr.write_str("[:^digit:]"),
351	0	Digit => self.wtr.write_str("[:digit:]"),
352	0	Graph if ast.negated => self.wtr.write_str("[:^graph:]"),
353	0	Graph => self.wtr.write_str("[:graph:]"),
354	0	Lower if ast.negated => self.wtr.write_str("[:^lower:]"),
355	0	Lower => self.wtr.write_str("[:lower:]"),
356	0	Print if ast.negated => self.wtr.write_str("[:^print:]"),
357	0	Print => self.wtr.write_str("[:print:]"),
358	0	Punct if ast.negated => self.wtr.write_str("[:^punct:]"),
359	0	Punct => self.wtr.write_str("[:punct:]"),
360	0	Space if ast.negated => self.wtr.write_str("[:^space:]"),
361	0	Space => self.wtr.write_str("[:space:]"),
362	0	Upper if ast.negated => self.wtr.write_str("[:^upper:]"),
363	0	Upper => self.wtr.write_str("[:upper:]"),
364	0	Word if ast.negated => self.wtr.write_str("[:^word:]"),
365	0	Word => self.wtr.write_str("[:word:]"),
366	0	Xdigit if ast.negated => self.wtr.write_str("[:^xdigit:]"),
367	0	Xdigit => self.wtr.write_str("[:xdigit:]"),
368		}
369	0	}
370
371	0	fn fmt_class_unicode(&mut self, ast: &ast::ClassUnicode) -> fmt::Result {
372		use crate::ast::ClassUnicodeKind::*;
373		use crate::ast::ClassUnicodeOpKind::*;
374
375	0	if ast.negated {
376	0	self.wtr.write_str(r"\P")?;
377		} else {
378	0	self.wtr.write_str(r"\p")?;
379		}
380	0	match ast.kind {
381	0	OneLetter(c) => self.wtr.write_char(c),
382	0	Named(ref x) => write!(self.wtr, "{{{}}}", x),
383	0	NamedValue { op: Equal, ref name, ref value } => {
384	0	write!(self.wtr, "{{{}={}}}", name, value)
385		}
386	0	NamedValue { op: Colon, ref name, ref value } => {
387	0	write!(self.wtr, "{{{}:{}}}", name, value)
388		}
389	0	NamedValue { op: NotEqual, ref name, ref value } => {
390	0	write!(self.wtr, "{{{}!={}}}", name, value)
391		}
392		}
393	0	}
394		}
395
396		#[cfg(test)]
397		mod tests {
398		use super::Printer;
399		use crate::ast::parse::ParserBuilder;
400
401		fn roundtrip(given: &str) {
402		roundtrip_with(\|b\| b, given);
403		}
404
405		fn roundtrip_with<F>(mut f: F, given: &str)
406		where
407		F: FnMut(&mut ParserBuilder) -> &mut ParserBuilder,
408		{
409		let mut builder = ParserBuilder::new();
410		f(&mut builder);
411		let ast = builder.build().parse(given).unwrap();
412
413		let mut printer = Printer::new();
414		let mut dst = String::new();
415		printer.print(&ast, &mut dst).unwrap();
416		assert_eq!(given, dst);
417		}
418
419		#[test]
420		fn print_literal() {
421		roundtrip("a");
422		roundtrip(r"\[");
423		roundtrip_with(\|b\| b.octal(true), r"\141");
424		roundtrip(r"\x61");
425		roundtrip(r"\x7F");
426		roundtrip(r"\u0061");
427		roundtrip(r"\U00000061");
428		roundtrip(r"\x{61}");
429		roundtrip(r"\x{7F}");
430		roundtrip(r"\u{61}");
431		roundtrip(r"\U{61}");
432
433		roundtrip(r"\a");
434		roundtrip(r"\f");
435		roundtrip(r"\t");
436		roundtrip(r"\n");
437		roundtrip(r"\r");
438		roundtrip(r"\v");
439		roundtrip(r"(?x)\ ");
440		}
441
442		#[test]
443		fn print_dot() {
444		roundtrip(".");
445		}
446
447		#[test]
448		fn print_concat() {
449		roundtrip("ab");
450		roundtrip("abcde");
451		roundtrip("a(bcd)ef");
452		}
453
454		#[test]
455		fn print_alternation() {
456		roundtrip("a\|b");
457		roundtrip("a\|b\|c\|d\|e");
458		roundtrip("\|a\|b\|c\|d\|e");
459		roundtrip("\|a\|b\|c\|d\|e\|");
460		roundtrip("a(b\|c\|d)\|e\|f");
461		}
462
463		#[test]
464		fn print_assertion() {
465		roundtrip(r"^");
466		roundtrip(r"$");
467		roundtrip(r"\A");
468		roundtrip(r"\z");
469		roundtrip(r"\b");
470		roundtrip(r"\B");
471		}
472
473		#[test]
474		fn print_repetition() {
475		roundtrip("a?");
476		roundtrip("a??");
477		roundtrip("a*");
478		roundtrip("a*?");
479		roundtrip("a+");
480		roundtrip("a+?");
481		roundtrip("a{5}");
482		roundtrip("a{5}?");
483		roundtrip("a{5,}");
484		roundtrip("a{5,}?");
485		roundtrip("a{5,10}");
486		roundtrip("a{5,10}?");
487		}
488
489		#[test]
490		fn print_flags() {
491		roundtrip("(?i)");
492		roundtrip("(?-i)");
493		roundtrip("(?s-i)");
494		roundtrip("(?-si)");
495		roundtrip("(?siUmux)");
496		}
497
498		#[test]
499		fn print_group() {
500		roundtrip("(?i:a)");
501		roundtrip("(?P<foo>a)");
502		roundtrip("(a)");
503		}
504
505		#[test]
506		fn print_class() {
507		roundtrip(r"[abc]");
508		roundtrip(r"[a-z]");
509		roundtrip(r"[^a-z]");
510		roundtrip(r"[a-z0-9]");
511		roundtrip(r"[-a-z0-9]");
512		roundtrip(r"[-a-z0-9]");
513		roundtrip(r"[a-z0-9---]");
514		roundtrip(r"[a-z&&m-n]");
515		roundtrip(r"[[a-z&&m-n]]");
516		roundtrip(r"[a-z--m-n]");
517		roundtrip(r"[a-z~~m-n]");
518		roundtrip(r"[a-z[0-9]]");
519		roundtrip(r"[a-z[^0-9]]");
520
521		roundtrip(r"\d");
522		roundtrip(r"\D");
523		roundtrip(r"\s");
524		roundtrip(r"\S");
525		roundtrip(r"\w");
526		roundtrip(r"\W");
527
528		roundtrip(r"[[:alnum:]]");
529		roundtrip(r"[[:^alnum:]]");
530		roundtrip(r"[[:alpha:]]");
531		roundtrip(r"[[:^alpha:]]");
532		roundtrip(r"[[:ascii:]]");
533		roundtrip(r"[[:^ascii:]]");
534		roundtrip(r"[[:blank:]]");
535		roundtrip(r"[[:^blank:]]");
536		roundtrip(r"[[:cntrl:]]");
537		roundtrip(r"[[:^cntrl:]]");
538		roundtrip(r"[[:digit:]]");
539		roundtrip(r"[[:^digit:]]");
540		roundtrip(r"[[:graph:]]");
541		roundtrip(r"[[:^graph:]]");
542		roundtrip(r"[[:lower:]]");
543		roundtrip(r"[[:^lower:]]");
544		roundtrip(r"[[:print:]]");
545		roundtrip(r"[[:^print:]]");
546		roundtrip(r"[[:punct:]]");
547		roundtrip(r"[[:^punct:]]");
548		roundtrip(r"[[:space:]]");
549		roundtrip(r"[[:^space:]]");
550		roundtrip(r"[[:upper:]]");
551		roundtrip(r"[[:^upper:]]");
552		roundtrip(r"[[:word:]]");
553		roundtrip(r"[[:^word:]]");
554		roundtrip(r"[[:xdigit:]]");
555		roundtrip(r"[[:^xdigit:]]");
556
557		roundtrip(r"\pL");
558		roundtrip(r"\PL");
559		roundtrip(r"\p{L}");
560		roundtrip(r"\P{L}");
561		roundtrip(r"\p{X=Y}");
562		roundtrip(r"\P{X=Y}");
563		roundtrip(r"\p{X:Y}");
564		roundtrip(r"\P{X:Y}");
565		roundtrip(r"\p{X!=Y}");
566		roundtrip(r"\P{X!=Y}");
567		}
568		}