Function winnow::multi::length_count

pub fn length_count<I, O, C, N, E, F, G>(f: F, g: G) -> impl Parser<I, C, E>where
    I: Stream,
    N: ToUsize,
    C: Accumulate<O>,
    F: Parser<I, N, E>,
    G: Parser<I, O, E>,
    E: ParseError<I>,

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.

Example

use winnow::Bytes;
use winnow::number::u8;
use winnow::multi::length_count;
use winnow::bytes::tag;

type Stream<'i> = &'i Bytes;

fn stream(b: &[u8]) -> Stream<'_> {
    Bytes::new(b)
}

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

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