Hi, suppose there are two (identical) classes:
> class Res a b | a -> b where > getRes :: a -> b and > class Res2 t where > type Member t > getRes2 :: t -> Member t It is easy to automatically make every instance of Res2 an instance of res: > instance Res2 a => Res a (Member a) where > getRes x = getRes2 x However, declaring every instance of Res an instance of Res2 seems impossible, as the following doesn't compile > instance Res a b => Res2 a where > type Member a = b > getRes2 x = getRes x Question is: How to do this? The reason I need it is because I use a library which uses functional dependencies, but my classes shall be type families. Regards, Henning _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
