On Mon, Dec 18, 2006 at 06:52:41PM -0800, Iavor Diatchki wrote: > Hi David, > > I don't think you need functional dependencies or associated > type synonyms to get your example to work. In the past, > I have used the abstraction that you are describing (I call it > an "indexed monad" and it has a nice categorical definition).
The trouble is that your solution doesn't allow you to use do-notation with the IxMonad. And if you did allow yourself to use do-notation by rebinding (>>=), etc, then you wouldn't be able to use ordinary monads with do-notation in the same module. That's what makes things tricky, since an IxMonad is different-kinded from Monad, so you can't make a monad an instance of IxMonad. David _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
