I'm learning how to use typeclasses for the first time, and I tried something like so: [CODE] data Point a = Point a a getX (Point a _) = a getY (Point _ a) = a instance Eq Point where (==) a b = getX a == getX b && getY a == getY b [/CODE] But when I try to load this in GHCI I get: [CODE] `Point' is not applied to enough type arguments The first argument of `Eq' should have kind `*', but `Point' has kind `* -> *' In the instance declaration for `Eq Point' [/CODE] This seems to be saying that Eq requires a concrete argument, which I suppose I can understand. I can fix this by changing "data Point a = Point a a" into "data Point = Point Int Int" or something like that, but that seems kind of lame: what if I want to leave my Point type more generic? (Maybe sometimes I'll need a Point Int, and other times I'll need a Point Float, or some other weird combination I haven't thought of yet.) Instead of changing the "data" declaration, can I change the "instance" declaration somehow so that it just defines an instance for a particular Point sub-type? I tried some variations like "instance Eq (Point Float)" but I haven't been able to come up with anything yet that satisfies the compiler. -- frigidcode.com theologia.indicium.us