On Jul 27, 2015, at 10:36 AM, Gabor Greif <ggr...@gmail.com> wrote: > When saying "Big Deal" did you mean > - highly desirable and somebody should go for it > - or a terrible amount of work, and who tackles it is probably a > fool on a hubris trip? > > (I still have my problems deciphering British irony.)
My use of Big Deal here is more your second option, but without so much negativity. :) I'm sure the person who tackled this problem would learn a ton and contribute to programming language research. It's just that we haven't yet found a great motivation for doing so. > > I guess a full-blown solution is too much work for now (also considering > previous comments from Richard). But what about a simpler construct > > decideRefl :: Proxy (a :: Symbol) -> Proxy b > -> Proxy (Equal a b :~: 'False) > -> Either (Equal a b :~: 'False) (a :~: b) I believe that this function could be written only with the help of unsafeCoerce. Indeed, the `singletons` package provides an `SDecide` instance for the type-lits (which accomplishes a similar, though not identical, goal) via unsafeCoerce. Richard _______________________________________________ ghc-devs mailing list ghc-devs@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs
