[apologies to Bulat for the repeat posting] On Thu, Sep 21, 2006 at 12:05:23PM +0400, Bulat Ziganshin wrote: > now i'm reading Haskell' proposals and found that these two things > considered as different: > > http://hackage.haskell.org/trac/haskell-prime/wiki/ExistentialQuantification > http://hackage.haskell.org/trac/haskell-prime/wiki/PolymorphicComponents > > can you please explain me what is the difference between > > data Ex = forall a. Num a => Ex a > > and > > data Po = Po (forall a. Num a => a)
Consider the types of the constructors: Ex :: forall a. (Num a) => a -> Ex Po :: (forall a. (Num a) => a) -> Po _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe