Macro nom::not

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

not!(I -> IResult<I,O>) => I -> IResult<I, ()> returns a result only if the embedded parser returns Error or Err(Err::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, Ok((&b"d"[..], &b"abc"[..])));

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