Re: [Haskell-cafe] typeclass question

| class ToRenderable a b where | toRenderable :: a -> Renderable b

But the above is, I think, too general for my needs. I don't want to be able to generate Renderables of different type b for a single input type a.

Sounds like a functional dependency (class ToReadable a b | a -> b )

Also, MPTC take me out of the world of haskell 98, which I was trying to avoid.

Why. "Everyone does it", and MPTC will be in Haskell-Prime (but FD may be not) http://hackage.haskell.org/trac/haskell-prime/wiki/MultiParamTypeClassesDile... J.W.