On Thu, May 01, 2008 at 03:42:53PM +0100, Simon Peyton-Jones wrote:
| Yeah, I disagree here, mainly because I don't want to conflate | superclasses with class aliases. I feel they have different uses, even | though they can sometimes achieve the same thing.
Fair enough. But the strange syntax
class alias Num a = Eq a => (Additive a, Multiplicative a)
*does* seem so say that the (Eq a) behaves in a superclass way, and (Additive a, Multiplicative a) behave in a class-alias way, as it were. That seems inconsistent with the design goal you describe above.
Wolfgang suggested the alternate syntax class alias Eq a => Num a = (Additive a, Multiplicative a) where .... The correct reading being: if 'Eq a' then 'Num a' is an alias for (Additive a,Multiplicative a) I think I am coming around to his point of view, do you think this makes it clearer? John -- John Meacham - ⑆repetae.net⑆john⑈