On Tue, 2006-03-28 at 14:32 +0100, Simon Peyton-Jones wrote: > My current take, FWIW. > > * MPTCs are very useful. They came along very rapidly (well before > H98). I think we must put them in H' > > * But MPTCs are hamstrung without FDs or ATs > > * FDs and ATs are of the same order of technical difficulty, as Martin > says > > * ATs are (I believe) a bit weaker from the expressiveness point of view > (zip example), but are (I believe) nicer to program with. > > * BUT we have way more experience with actually programming with FDs. > ATs fail the "well-established" test by a mile. > > * Largely due to Martin's work, we now have a much better handle on just > what restrictions on FDs make type inference tractable. So I believe > there is a solid MPTC+FD story that we could embody in H'. > > * Medium term, I think ATs may *at the programming-language level* > displace FDs, because they are nicer to program with. But that's just > my opinion, and we don't have enough experience to know one way or the > other.
This analysis is similar to what I have here: http://hackage.haskell.org/trac/haskell-prime/wiki/MultiParamTypeClassesDilemma Could someone flesh out the wiki w/ Simon's data and links to the new information from Martin? peace, isaac _______________________________________________ Haskell-prime mailing list [email protected] http://haskell.org/mailman/listinfo/haskell-prime
