On 14 Apr 2010, at 09:25, Ashley Yakeley wrote: > Thomas Davie wrote: >> Because we consider that the Functor laws must hold for all values in the >> type (including bottom). > > This is not so for IO, which is an instance of Functor. "fmap id undefined" > is not bottom.
It isn't? fPrelude> fmap id (undefined :: IO ()) *** Exception: Prelude.undefined Bob_______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
