Function chumsky::primitive::filter

pub fn filter<I, F: Fn(&I) -> bool, E>(f: F) -> Filter<F, E>

A parser that accepts only inputs that match the given predicate.

The output type of this parser is I, the input that was found.

Examples

let lowercase = filter::<_, _, Cheap<char>>(char::is_ascii_lowercase)
    .repeated().at_least(1)
    .then_ignore(end())
    .collect::<String>();

assert_eq!(lowercase.parse("hello"), Ok("hello".to_string()));
assert!(lowercase.parse("Hello").is_err());