Ashley Yakeley wrote: > > At 2002-01-21 00:25, Janis Voigtlaender wrote: > > >Hope that helps and doesn't just make the story more obscure ;-) > > I'm not convinced. Here's a simplified case... > > This compiles fine: > > emptyList :: [a] > emptyList = [] > > isempty :: Bool > isempty = null emptyList > > But this gives an error: > > emptyList :: (Ord a) => [a] > emptyList = [] > > isempty :: Bool > isempty = null emptyList > > ...
Ok, it seems that the type error in Daniel's program occured for a simpler reason than I suspected. But my objection to the program persists: to have a polymorphic (==) that compares lists with the same element types is different from having a (==) that compares polymorphic lists. -- Janis Voigtlaender http://wwwtcs.inf.tu-dresden.de/~voigt/ mailto:[EMAIL PROTECTED] _______________________________________________ Haskell mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell
