Hi, (Relatively new to Haskell here ..) So I have the following: data MyVal = Atom String | Bool Bool And I want to do something like this check :: (Bool -> MyVal) -> MyVal -> True check f (f x) = True check _ _ = False What that means is I want to pass a MyVal constructor and a MyVal, and return True if the second argument was constructed with the first. More generally, I'd like to be able to do genCheck :: (* -> MyVal) -> MyVal -> True genCheck f (f x) = True genCheck _ _ = False So that I can pass in _any_ MyVal constructor and let the function just check if the second argument was constructed with the first, without caring which constructor it is. What is the preferred way to do this, since neither of those functions compile? Cheers, - Dan