On Tue, Mar 13, 2007 at 11:12:40AM +0000, Neil Mitchell wrote:
As for Stefan's ordNub, I think it is a great idea to add along with sortNub - this really does give people a nicer set of Nub functions. My only worry is that the dependency on State and Set will make the implementation have cyclic dependency fun.
once we have ordNub, we can create lots of RULES like the following {-# RULES "nub/ordNub" nub = ordNub :: [String] -> [String] #-} {-# RULES "nub/ordNub" nub = ordNub :: [Int] -> [Int] #-} {-# RULES "nub/ordNub" nub = ordNub :: [Integer] -> [Integer] #-} actually, we probably want one that uses IntMap for ints. it is signifigantly faster. I don't suppose there is a way to match a RULE to a class constraint? I don't see how it would be implemented in any easy way since classes get desugared away pretty early... but it would be an interesting feature.. {-# RULES "nub/ordNub" forall (a::*) . Ord a => nub = ordNub :: [a] -> [a] #-} or something... John -- John Meacham - ⑆repetae.net⑆john⑈