On 2006-03-24, Henning Thielemann <[EMAIL PROTECTED]> wrote: > > 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?
Torsor is not quite the right word -- it's just that one of the contexts for non-negative numbers is very similar to one fairly standard example of torsors -- pointers and offsets. >> 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? A strawman proposal, not yet posted anywhere. > Without breaking compatibility? > But class instances become invalid if the hierarchy is modified. No, compatibility will be broken. Hopefully not for most uses -- I don't think most people define new instances, and those that do will be able to do so more reasonably, so hopefully wouldn't mind. > 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. :-) Not at all. That is one of the things I looked at a while ago, that has inspired a lot of my decisions -- but I'm more willing to rename things that I think have silly names. And there are a few minor details, like allowing only for euclidean domains rather than principal ideal domains. I will probably actually put two proposals up, with one allowing more generality via MPTCs and FDs (which I truly hope make it into the standard). -- Aaron Denney -><- _______________________________________________ Haskell-Cafe mailing list [email protected] http://www.haskell.org/mailman/listinfo/haskell-cafe
