On Tue, Jun 21, 2011 at 2:24 PM, pipoca <eliyahu.ben.mi...@gmail.com> wrote:
> On Jun 21, 4:57 pm, Alexey Khudyakov <alexey.sklad...@gmail.com> > wrote: > > Types may be same. > > > > oops :: Int :+: Int -> Int > > oops <Int i> = mmm which one? > > If you were to have your anonymous sum types be a union instead of the > disjoint union, then you could say that A :+: A has no meaning. > That sort of union would not be parametric, and would play havoc with generic programming. E.g. consider taking a list [(t,Int)] and [(t,a)] and generating a list of [(t,Int :+: a)], then processing this with a function of the form Int -> Bool.
_______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
