[Haskell-cafe] Re: Positive integers

[ihope]

On 3/29/06, Aaron Denney <wnoise at ofb.net> wrote:
> (And yes, we desperately need something like class aliases.)

You mean like this?

class Foo a b where
  foo :: a -> b

class Foo a b => Bar a b where

instance Foo a b => Bar a b where

This will make every instance of Foo one of Bar, and make sure every
instance of Bar is an instance of Foo.