Function winnow::combinator::not

pub fn not<I: Stream, O, E: ParseError<I>, F>(
    parser: F
) -> impl FnMut(I) -> IResult<I, (), E>where
    F: Parser<I, O, E>,

Succeeds if the child parser returns an error.

Note: This does not advance the Stream

Example

use winnow::combinator::not;
use winnow::character::alpha1;

let mut parser = not(alpha1);

assert_eq!(parser("123"), Ok(("123", ())));
assert_eq!(parser("abcd"), Err(ErrMode::Backtrack(Error::new("abcd", ErrorKind::Not))));