Function lip::either

pub fn either<'a, A, P: 'a, S: Clone + 'a>(
    parser1: P, 
    parser2: P
) -> BoxedParser<'a, A, S> where
    P: Parser<'a, A, S>, 

Choose either the left parser or the right parser to parse.

For choosing between more than two parsers, use one_of!