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

[David Thomas]

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 <winterkoninkje at gmail.com> wrote:
> On Mon, Sep 7, 2015 at 10:08 AM, DreamApart AtHaskells
> <rnmss.hs at gmail.com> 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
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