I would guess that the reason is that it hasn't been implemented yet... ...still it does seem to be a real shame if nothing in this area can make it into Haskell' .... (and it's not just Num .... Monad inheriting from Functor etc) ...it's a lot less sexy than something like TF, but I think it'd add a huge amount of value from the pragmatic point of view. --Ben On 21 Apr 2008, at 19:40, Jacques Carette wrote:
I tried to see the discussion that led to class aliases being rejected as a proposal, but could not find links on the Wiki. In fact, in Trac (#101) that proposal is still a 'maybe', but with no updates. Is there a competing proposal that got accepted?
[Without a mechanism like class aliases, breaking up Num into a hierarchy of proper mathematical concepts becomes too unwieldly to be realistic. This is a real stumbling block for anyone trying to use the class system to encode fine-grained mathematical concepts.]
Jacques _______________________________________________ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime