diff options
Diffstat (limited to 'third_party/rust/regex-syntax/src/ast/print.rs')
| -rw-r--r-- | third_party/rust/regex-syntax/src/ast/print.rs | 568 |
1 files changed, 568 insertions, 0 deletions
diff --git a/third_party/rust/regex-syntax/src/ast/print.rs b/third_party/rust/regex-syntax/src/ast/print.rs new file mode 100644 index 0000000000..045de2eaf2 --- /dev/null +++ b/third_party/rust/regex-syntax/src/ast/print.rs @@ -0,0 +1,568 @@ +/*! +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}"); + } +} |