On Monday 18 August 2003 19:26, Brandon Michael Moore wrote:
I think what you want are functional dependencies. ...
Bingo! That's what I needed. I had tried something like that before, but I had started from a fundamental misunderstanding: I had assumed that class Vect v a where... would automatically make 'v' a type constructor, and all my experiments using that assumption plus dependencies produced rather useless results. What I have now satisfies all my needs (at least my current needs...), and it works with GHC. Hugs hangs in some places, but I guess that's another problem entirely.
The GHC users guide, the Haskell Wiki, and the paper "Type Classes: Exploring the Design Space" are all good places for more information.
Thanks, I'll look at all that... Konrad.