Everyone agrees that the Haskell numeric hierarchy is flawed, but I've yet to see a good replacement.
On Mon, Oct 5, 2009 at 4:51 PM, Brad Larsen <brad.lar...@gmail.com> wrote: > On Mon, Oct 5, 2009 at 10:36 AM, Miguel Mitrofanov > <miguelim...@yandex.ru> wrote: > [...] >> Of course, it's OK to call anything "numbers" provided that you stated >> explicitly what exactly you would mean by that. But then you have to drop >> all kind of stuff mathematicians developed for the usual notion of numbers. >> In the same way, you shouldn't use the "Num" class for your "numbers". >> >> On the other hand, people can (ab)use the "Num" class as they wish, and it's >> their business until they ask a question about it somewhere outside - which >> makes the business not only theirs. > [...] > > The Num class has `negate' as part of its definition. Natural numbers > are numbers, but I don't believe there is any sensible definition of > `negate' for them. > > Haskell 98's numeric hierarchy combines many operations which should > be separate. As further evidence, every bit of Haskell I have seen > that does symbolic manipulation of numeric expressions either leaves > out instances that would make the syntax more convenient, or else > defines partial instances because certain class functions have no > sensible definition for symbolic expressions. > > Sincerely, > Brad > _______________________________________________ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe > _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
