Function gchemol_parser::parsers::not

pub fn not<I, O, E, F>(parser: F) -> impl Fn(I) where
    E: ParseError<I>,
    F: Fn(I) -> Result<(I, O), Err<E>>,
    I: Clone, 

succeeds if the child parser returns an error

use nom::combinator::not;
use nom::character::complete::alpha1;

let parser = not(alpha1);

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