Macro abortable_parser::not

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

Turns a matcher into it’s inverse, only succeeding if the the matcher returns a Fail. Does not consume it’s input and only returns ().

let tok = not!(iter, text_token!("bar"));
assert!(tok.is_complete());
if let Result::Complete(i, o) = tok {
    assert_eq!(i.get_offset(), 0);
    assert_eq!(o, ());
}