Function combine::range::take_while

pub fn take_while<I, F>(f: F) -> TakeWhile<I, F> where
    I: RangeStream,
    F: FnMut(I::Item) -> bool, 

Zero-copy parser which reads a range of 0 or more tokens which satisfy f.

let mut parser = take_while(|c: char| c.is_digit(10));
let result = parser.parse("123abc");
assert_eq!(result, Ok(("123", "abc")));
let result = parser.parse("abc");
assert_eq!(result, Ok(("", "abc")));