+

Crate regex_syntax + + [−] + + [src]

+

This crate provides a regular expression parser and an abstract syntax for +regular expressions. The abstract syntax is defined by the Expr type. The +concrete syntax is enumerated in the +regex +crate documentation.

+ +

Note that since this crate is first and foremost an implementation detail for +the regex crate, it may experience more frequent breaking changes. It is +exposed as a separate crate so that others may use it to do analysis on regular +expressions or even build their own matching engine.

+ +

Example: parsing an expression

+

Parsing a regular expression can be done with the Expr::parse function.

+

+use regex_syntax::Expr;
+
+assert_eq!(Expr::parse(r"ab|yz").unwrap(), Expr::Alternate(vec![
+    Expr::Literal { chars: vec!['a', 'b'], casei: false },
+    Expr::Literal { chars: vec!['y', 'z'], casei: false },
+]));
+

+ +

Example: inspecting an error

+

The parser in this crate provides very detailed error values. For example, +if an invalid character class range is given:

+

+use regex_syntax::{Expr, ErrorKind};
+
+let err = Expr::parse(r"[z-a]").unwrap_err();
+assert_eq!(err.position(), 4);
+assert_eq!(err.kind(), &ErrorKind::InvalidClassRange {
+    start: 'z',
+    end: 'a',
+});
+

+ +

Or unbalanced parentheses:

+

+use regex_syntax::{Expr, ErrorKind};
+
+let err = Expr::parse(r"ab(cd").unwrap_err();
+assert_eq!(err.position(), 2);
+assert_eq!(err.kind(), &ErrorKind::UnclosedParen);
+

+

Structs

+ + + + + + + + + + + + + + + +

CharClass	+ A character class. + +
ClassRange	+ A single inclusive range in a character class. + +
Error	+ A parse error. + +

Enums

+ + + + + + + + + + + + + + + +

ErrorKind	+ The specific type of parse error that can occur. + +
Expr	+ A regular expression abstract syntax tree. + +
Repeater	+ The type of a repeat operator expression. + +