Re: [Haskell-cafe] Thoughts about redesigning "Num" type class

I think we definitely want to keep subtraction separate, and maybe even allow for a subtraction operation that returns a different type... On Fri, Sep 11, 2015 at 7:05 PM, wren romano wrote:

On Mon, Sep 7, 2015 at 10:08 AM, DreamApart AtHaskells wrote:

...

A feasible design is: [...]

I'm all for redesigning the numeric hierarchy, but I must (once again) raise my standard complaint against this sort of work, namely: there must be a class for semirings.

Abelian groups are nice and all, but they are not the principle origin for rings. There are far more objects which have addition/multiplication without subtraction than there are objects with addition/subtraction without multiplication. Everyone I've seen suggest redesigning Num keeps overlooking this fact, since they're all so hung up on module/vector spaces.

-- Live well, ~wren _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe