Sönke Hahn schrieb: > Hi! > > I often stumble upon 2- (or 3-) dimensional numerical data types like > > (Double, Double) > > or similar self defined ones. I like the idea of creating instances for Num > for > these types. The meaning of (+), (-) and negate is clear and very intuitive, > i > think. I don't feel sure about (*), abs, signum and fromInteger. 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. > > Any thoughts on that? How would you do it?
I use NumericPrelude that has more fine grained type classes. E.g. (+) is in Additive and (*) is in Ring. http://hackage.haskell.org/package/numeric-prelude _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
