Import 'regex-syntax' package vesion 0.6.17
* Add OWNERS
Bug: 152884384
Test: make
Change-Id: I760a69ffc851039ceaff58980deece308a426aed
diff --git a/src/ast/print.rs b/src/ast/print.rs
new file mode 100644
index 0000000..1b9bc41
--- /dev/null
+++ b/src/ast/print.rs
@@ -0,0 +1,569 @@
+/*!
+This module provides a regular expression printer for `Ast`.
+*/
+
+use std::fmt;
+
+use ast::visitor::{self, Visitor};
+use 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 { printer: self, wtr: wtr })
+ }
+}
+
+#[derive(Debug)]
+struct Writer<'p, W> {
+ printer: &'p mut Printer,
+ wtr: W,
+}
+
+impl<'p, W: fmt::Write> Visitor for Writer<'p, 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 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 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<'p, W: fmt::Write> Writer<'p, W> {
+ fn fmt_group_pre(&mut self, ast: &ast::Group) -> fmt::Result {
+ use 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 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 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 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 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 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 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 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 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 ast::ClassUnicodeKind::*;
+ use 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 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}");
+ }
+}