nom::bytes::complete

Function take_while

Source
pub fn take_while<F, Input, Error: ParseError<Input>>(
    cond: F,
) -> impl Fn(Input) -> IResult<Input, Input, Error>
where Input: InputTakeAtPosition, F: Fn(<Input as InputTakeAtPosition>::Item) -> bool,
Expand description

Returns the longest input slice (if any) that matches the predicate.

The parser will return the longest slice that matches the given predicate (a function that takes the input and returns a bool).

ยงExample

use nom::bytes::complete::take_while;
use nom::character::is_alphabetic;

fn alpha(s: &[u8]) -> IResult<&[u8], &[u8]> {
  take_while(is_alphabetic)(s)
}

assert_eq!(alpha(b"latin123"), Ok((&b"123"[..], &b"latin"[..])));
assert_eq!(alpha(b"12345"), Ok((&b"12345"[..], &b""[..])));
assert_eq!(alpha(b"latin"), Ok((&b""[..], &b"latin"[..])));
assert_eq!(alpha(b""), Ok((&b""[..], &b""[..])));