[Haskell-cafe] Playing with ATs again

[Andrew Coppin]

Victor Nazarov wrote:
> I think it is more simple like:
>
> class Bijection a b where
>   ...
>
> type LeftToRight a = (Bijection a b) => b
> type RightToLeft b = (Bijection a b) => a
>   

Hmm, yes... That looks like it could work.