On Feb 13, 2009, at 1:38 PM, Daniel Fischer wrote:
? Well, still easy, we must unify with (a -> b) -> c -> [d], only one possibility, fine. Or is it? What if we have another 'take' in scope? Say take :: Int -> Set a -> Set a ? Oops. So, where draw the line?
You draw the line exactly when you cannot perform unambiguous typing.
Bottom line, allowing that sort of overloading would at least be very ad-hoccish, and probably a bad thing.
Why? All existing programs would type check and run without modification. So if you really like type class abuse and a billion pseudonyms for '+' (among others), then you would still have the option of developing in that style. On the other hand, if you wanted the machine to do what a human can (which is, deciding in completely unambiguous cases which of several definitions to use), then you'd be able to use name overloading and make some programs a lot more readable. Regards, John A. De Goes N-BRAIN, Inc. The Evolution of Collaboration http://www.n-brain.net | 877-376-2724 x 101