On Tue, May 28, 2013 at 09:09:48PM +0200, Johannes Gerer wrote: > What about these two very simple type classes. Are they equivalent? [...] > class Pointed f where > pure :: a -> f a > > class Unit f where > unit :: f a a > > newtype UnitPointed f a = UnitPointed f a a > instance Unit f => Pointed (UnitPointed f) where > pure f = UnitPointed unit > > newtype Kleisli f a b = Kleisli (a -> f b) > instance Pointed f => Unit (Kleisli f) where > unit = Kleisli pure
This is implausible, since "pure f" does not depend on "f". _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
