# Function nom::multi::length_count

source · [−]

    pub fn length_count<I, O, N, E, F, G>(
        f: F,
        g: G
    ) -> impl FnMut(I) -> IResult<I, Vec<O>, E> where
        I: Clone,
        N: ToUsize,
        F: Parser<I, N, E>,
        G: Parser<I, O, E>,
        E: ParseError<I>,

Expand description

Gets a number from the first parser, then applies the second parser that many times.

## Arguments

- `f` The parser to apply to obtain the count.
- `g` The parser to apply repeatedly.

    use nom::number::complete::u8;
    use nom::multi::length_count;
    use nom::bytes::complete::tag;
    use nom::combinator::map;

    fn parser(s: &[u8]) -> IResult<&[u8], Vec<&[u8]>> {
      length_count(map(u8, |i| {
         println!("got number: {}", i);
         i
      }), tag("abc"))(s)
    }

    assert_eq!(parser(&b"\x02abcabcabc"[..]), Ok(((&b"abc"[..], vec![&b"abc"[..], &b"abc"[..]]))));
    assert_eq!(parser(b"\x03123123123"), Err(Err::Error(Error::new(&b"123123123"[..], ErrorKind::Tag))));