Function combine::position

pub fn position<I>() -> Position<I> where
    I: Stream, 

Parser which just returns the current position in the stream.

let result = (position(), token('!'), position())
    .parse(State::new("!"))
    .map(|x| x.0);
assert_eq!(result, Ok((SourcePosition { line: 1, column: 1 },
                       '!',
                       SourcePosition { line: 1, column: 2 })));