On Fri, 24 Mar 2006, Aaron Denney wrote:
Basically, my big objection is that it's hard to define many useful operations on them that are statically safe.
Why not defining the Torsor class you suggested?
Any definition of Num a for instance leaves a whole bunch of unsafe methods, or just plain inapplicable methods, such as "negate".
Yes Num class is quite inappropriate.
Now granted, the numeric hierarchy should be broken up a bit (hmm, I should finish my strawman proposal for Haskell'), but even then I see problems.
Hm, is there something going on? Without breaking compatibility? But class instances become invalid if the hierarchy is modified. If there is some progress towards a refined numeric class hierarchy I want to point again to http://cvs.haskell.org/darcs/numericprelude/ http://cvs.haskell.org/darcs/numericprelude/src/Algebra/Core.lhs I hope I don't annoy you. :-)