Matt Harden
zip :: ZipFunctor f => f a -> f b -> f (a,b) zip = zipWith (,) zip3 :: ZipFunctor f => f a -> f b -> f c -> f (a,b,c) zip3 = zipWith3 (,,)
One can easily create ZipFunctor instances for trees and other data structures. I can provide examples if you like. With multiple parameter type classes (MPTCs, they are not in Haskell 98) as well as functional dependencies (also not in h98), one can also create a "Zippable" class to generalize the zip function over multiple tuple types and eliminate zip3, zip4, etc.
can you explain how you do that ?? (i dont know what is functional dependencies, but i think i understand multiple parameter type classes and i dont see how do make something that avoid to define a zip3 zip4 ....