Hi there, I'm learning haskell for weeks and I'm trying to write a parser using haskell. First I create a datatype: newtype Parser a = P (String -> [(a, String)]) I create a function called `bind` : bind :: Parser a -> ( a -> Parser b) -> Parser b bind f g = P $ \s -> concatMap (\(a, s') -> parse (g a) s') $ parse f s and then: instance Monad Parser where (>>=) = bind that's looks cool, than I write a function liftToken :: (Char -> [a]) -> Parser a liftToken f = P g where g [] = [] g (c:cs) = f c >>= (\x -> return (x, cs)) It works well, then I change this function to liftToken :: (Char -> [a]) -> Parser a liftToken f = P g where g [] = [] g (c:cs) = f c `bind` (\x -> return (x, cs)) GHC throw errors: regular.hs|153 col 14 error| • Couldn't match expected type ‘Parser t0’ with actual type ‘[a]’ • In the first argument of ‘bind’, namely ‘f c’ In the expression: f c `bind` (\ x -> return (x, cs)) In an equation for ‘g’: g (c : cs) = f c `bind` (\ x -> return (x, cs)) • Relevant bindings include f :: Char -> [a] (bound at regular.hs:151:11) liftToken :: (Char -> [a]) -> Parser a (bound at regular.hs:151:1) That's really confusing, why I can use (>>=) but I can't use `bind`? Is there any difference between them?