Macro peel_ip::prelude::not

macro_rules! not {
    ( $ i : expr , $ submac : ident ! ( $ ( $ args : tt ) * ) ) => { ... };
    ( $ i : expr , $ f : expr ) => { ... };
}

not!(I -> IResult<I,O>) => I -> IResult<I, O> returns a result only if the embedded parser returns Error or Incomplete does not consume the input

named!(not_e, do_parse!(
    res: tag!("abc")      >>
         not!(char!('e')) >>
    (res)
));

let r = not_e(&b"abcd"[..]);
assert_eq!(r, Done(&b"d"[..], &b"abc"[..]));

let r2 = not_e(&b"abce"[..]);
assert_eq!(r2, Error(error_position!(ErrorKind::Not, &b"e"[..])));