instance declaration troubles
Fri, 7 Mar 2003 03:22:38 +0100
I want to declare the following:
class Get a where
ls :: a b -> IO [b]
mk :: IO [b] -> a b
instance (Get a) => Functor a where
fmap f x = mk (ls x >>= return . map f)
But to have ghc type everything, I have to turn on "-fglasgow-exts
Is there a clean way to state that all types in my type class are also
in the "Functor" type class?
If not, what is the problem?