Function regex

pub fn regex<'h, Input, Re, Error>(
    re: Re,
) -> RegexParser<'h, Input, Re::Output, Error>
where
    Input: StreamIsPartial + Stream + Offset + Clone,
    Re: RegexPattern,
    Re::Output: Regex<Haystack<'h> = <Input as Stream>::Slice>,
    Re::Error: Debug,
    Error: ParserError<Input> + 'static,

Creates a parser that matches input using a regular expression.

This parser takes a regular expression pattern (implementing RegexPattern) and returns a parser that attempts to match from the beginning of the input. If the regular expression does not match at position 0, the parser fails.

Internally, this uses a precompiled Regex from the [regex] crate and supports both complete and partial input modes via the StreamIsPartial trait.

Panics

Panics if the regex pattern fails to compile.

Example

use winnow::prelude::*;
use winnow_regex::regex;

fn digits<'i>(s: &mut &'i str) -> ModalResult<&'i str> {
    regex(r"^\d+").parse_next(s)
}

assert_eq!(digits.parse_peek("42abc"), Ok(("abc", "42")));
assert!(digits.parse_peek("abc42").is_err());

// Example with precompiled regex
fn word<'i>(s: &mut &'i str) -> ModalResult<&'i str> {
    let re = regex::Regex::new(r"^\w+").unwrap();
    regex(re).parse_next(s)
}

assert_eq!(word.parse_peek("hello world"), Ok((" world", "hello")));
assert!(word.parse_peek("!hello").is_err());