Function hex_digit0

pub fn hex_digit0<T, E: ParseError<T>>(input: T) -> IResult<T, T, E>
where
    T: InputTakeAtPosition,
    <T as InputTakeAtPosition>::Item: AsChar,

Recognizes zero or more ASCII hexadecimal numerical characters: 0-9, A-F, a-f

Complete version: Will return the whole input if no terminating token is found (a non hexadecimal digit character).

Example

fn parser(input: &str) -> IResult<&str, &str> {
    hex_digit0(input)
}

assert_eq!(parser("21cZ"), Ok(("Z", "21c")));
assert_eq!(parser("Z21c"), Ok(("Z21c", "")));
assert_eq!(parser(""), Ok(("", "")));