Function nom::bytes::streaming::take_while_m_n

pub fn take_while_m_n<F, Input, Error: ParseError<Input>>(
    m: usize, 
    n: usize, 
    cond: F
) -> impl Fn(Input) -> IResult<Input, Input, Error> where
    Input: InputTake + InputIter + InputLength + Slice<RangeFrom<usize>>,
    F: Fn(<Input as InputIter>::Item) -> bool, 

Returns the longest (m <= len <= n) input slice 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)

It will return an Err::Error((_, ErrorKind::TakeWhileMN)) if the pattern wasn’t met

Streaming Specific

Streaming version will return a Err::Incomplete(Needed::Size(1)) if the pattern reaches the end of the input or is too short.

Example

use nom::bytes::streaming::take_while_m_n;
use nom::character::is_alphabetic;

fn short_alpha(s: &[u8]) -> IResult<&[u8], &[u8]> {
  take_while_m_n(3, 6, is_alphabetic)(s)
}

assert_eq!(short_alpha(b"latin123"), Ok((&b"123"[..], &b"latin"[..])));
assert_eq!(short_alpha(b"lengthy"), Ok((&b"y"[..], &b"length"[..])));
assert_eq!(short_alpha(b"latin"), Err(Err::Incomplete(Needed::Size(1))));
assert_eq!(short_alpha(b"ed"), Err(Err::Incomplete(Needed::Size(1))));
assert_eq!(short_alpha(b"12345"), Err(Err::Error((&b"12345"[..], ErrorKind::TakeWhileMN))));