Am Freitag, 28. März 2008 05:21 schrieb Dan Doel: > […] > However, obviously, this depends on overlapping instances (if there's some > other way, I'd be happy to know; if type inequality contexts are available, > I wasn't able to find them), and I've heard that type families don't play > well with overlap. Does that not apply to data families? Will this > construction still work in 6.10 and beyond? > > Also, this doesn't seem to be a suitable basis for Dynamic. Trying to > extend the GADT solution presented resulted in errors unless incoherent > instances were turned on (clearly not a good sign), and even then, it > didn't actually work. Is it possible to do better, and come away with > something that will actually work for Dynamic, and be sound?
I don’t know exactly whether this helps here but with open type families you will be able to define a type-level type equality decision. See the mail at <http://www.haskell.org/pipermail/glasgow-haskell-users/2007-October/013271.html>. > […] Best wishes, Wolfgang _______________________________________________ Haskell-Cafe mailing list [email protected] http://www.haskell.org/mailman/listinfo/haskell-cafe
