That only works for type constructors (or similar encapsulation functions), but not for any sort of a -> b functions, i.e. (+1).
>How about this: > >liftTup :: (forall a. a -> f a) -> (x, y) -> (f x, f y) >liftTup f (x,y) = (f x, f y) > >Or ghc can infer the type if you write it like this: > >liftTup (f::forall a.a ->f a) (x::x,y::y) = (f x::f x, f y::f y) > >or simply: > >liftTup (f::forall a.a ->f a) (x,y) = (f x, f y) > > >It works too! (ghci -fglasgow-exts) > >> liftTup Just (1, 'c') >(Just 1,Just 'c') > >Duncan > >_______________________________________________ >Haskell mailing list >[EMAIL PROTECTED] >http://www.haskell.org/mailman/listinfo/haskell > _______________________________________________ Haskell mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell
