Function fill 

pub fn fill<'a, I, O, E, F>(f: F, buf: &'a mut [O]) -> impl FnMut(I) + 'a
where
    I: Clone + PartialEq,
    F: Fn(I) -> Result<(I, O), Err<E>> + 'a,
    E: ParseError<I>,

Available on crate feature crypto only.

Runs the embedded parser repeatedly, filling the given slice with results.

This parser fails if the input runs out before the given slice is full.

Arguments

• f The parser to apply.
• buf The slice to fill

use nom::multi::fill;
use nom::bytes::complete::tag;

fn parser(s: &str) -> IResult<&str, [&str; 2]> {
  let mut buf = ["", ""];
  let (rest, ()) = fill(tag("abc"), &mut buf)(s)?;
  Ok((rest, buf))
}

assert_eq!(parser("abcabc"), Ok(("", ["abc", "abc"])));
assert_eq!(parser("abc123"), Err(Err::Error(Error::new("123", ErrorKind::Tag))));
assert_eq!(parser("123123"), Err(Err::Error(Error::new("123123", ErrorKind::Tag))));
assert_eq!(parser(""), Err(Err::Error(Error::new("", ErrorKind::Tag))));
assert_eq!(parser("abcabcabc"), Ok(("abc", ["abc", "abc"])));