Hello all, I just hit a sticking point when trying to parse something like data Exp = Lit Int -- literal integer | Plus Exp Exp where something like "1+2" should be parsed to "Plus (Lit 1) (Lit 2)". When I try to parse "1+2" my parser enters an infinite loop. I can understand why: it thinks "hmm, this expression could be a plus, but then it must start with an expression, lets check". and it tries to parse expression again and again considers Plus. When I change the rules, so it first checks for "Lit", it does parse the "1" just fine, but then gives up, because the remainder is not an expression anymore, but just a "+2". My parser is written in the style shown in Graham Hutton's book: Parser a :: String -> (a, String). I believe I am missing something obvious, but I can't see it. -- Martin