This seems similar to my 'supertyping' proposal. The basic gist was that you can declare a superclass (which must have a subset of the members of the original class) after the declaration of the original class... my original message is here: http://repetae.net/john/computer/haskell/supertyping.txt John On Sun, Jan 12, 2003 at 09:37:25AM -0500, Dylan Thurston wrote:
On Wed, Jan 08, 2003 at 02:24:06PM +0100, Marc Ziegert wrote:
--------------------It would be nice to be able to overload class-functions like classes:
instance (+), (-) -> Vector where (+) v1 v2 = ... (-) v1 v2 = ... ...
You seem to be making a general complaint, but there's been extensive discussion about this particular instance. I agree with you that the numeric hierarchy is too coarsely grained right here; do a search on the archives for "numeric prelude" for an extensive discussion.
Your proposals seem interesting, but seem hard to implement/make precise at first glance.
Best, Dylan Thurston
-- --------------------------------------------------------------------------- John Meacham - California Institute of Technology, Alum. - john@foo.net ---------------------------------------------------------------------------