Am Montag 05 Oktober 2009 16:29:02 schrieb Job Vranish: > In what way is it not a number? >
If there's a natural[1] implementation of fromInteger, good. If there isn't, *don't provide one*. fromInteger _ = error "Not sensible" is better than doing something strange. [1] In the case of residue class rings, you may choose between restricting the range of legitimate arguments for fromInteger or doing a modulo operation on the argument, both ways are natural and meet expectations sufficiently well. > > Sönke Hahn: > btw, I forgot to mention in my first email, but > fromInteger n = (r, r) where r = fromInteger n > is better than: > fromInteger n = (fromInteger n, 0) > as you get a lot of corner cases otherwise. > > I use fromInteger = pure . fromInteger, which when combined with my > Applicative instance, is effectively the same as your: fromInteger n = (r, > r) where r = fromInteger n > > > - Job > > On Mon, Oct 5, 2009 at 9:12 AM, Miguel Mitrofanov > <miguelim...@yandex.ru>wrote: > > Sönke Hahn wrote: > > > > I used to implement > > > >> fromInteger n = (r, r) where r = fromInteger n > >> > >> , but thinking about it, > >> fromInteger n = (fromInteger n, 0) > >> > >> seems very reasonable, too. > > > > Stop pretending something is a number when it's not. _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
