Function nom::character::complete::hex_digit1

pub fn hex_digit1<T, E: ParseError<T>>(input: T) -> IResult<T, T, E> where
    T: InputTakeAtPosition,
    <T as InputTakeAtPosition>::Item: AsChar, 

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

complete version: Will return an error if there’s not enough input data, or the whole input if no terminating token is found (a non hexadecimal digit character).

Example

fn parser(input: &str) -> IResult<&str, &str> {
    hex_digit1(input)
}

assert_eq!(parser("21cZ"), Ok(("Z", "21c")));
assert_eq!(parser("H2"), Err(Err::Error(("H2", ErrorKind::HexDigit))));
assert_eq!(parser(""), Err(Err::Error(("", ErrorKind::HexDigit))));