On 1 Jan 2011, at 12:38, Andreas Baldeau wrote: > Thinking about this there might be one problem: > > Without having looked further into this I think perfomance might not > be as expected. Using unsafePerformIO affects ghc's optimzations, > doesn't it? > > So I wonder if it's a good idea (from a performance point of view) to > use this. > >> 2010/12/30 Andreas Baldeau <andr...@baldeau.net>: >>> instance Ord TypeRep where >>> compare t1 t2 = >>> compare >>> (unsafePerformIO (typeRepKey t1)) >>> (unsafePerformIO (typeRepKey t2)) > >>> typeRepKey :: TypeRep -> IO Int >>> typeRepKey (TypeRep (Key i) _ _) = return i > > So the question is, if ghc could transform this to simply compare the > keys throwing away unsafePerformIO and return.
Wouldn't a much better plan simply be to take typeRepKey out of the IO monad? Bob _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
