@@ -61,17 +61,3 @@ mapMaybe f (x::xs) =
61 case f x of
61 case f x of
62 Nothing => mapMaybe f xs
62 Nothing => mapMaybe f xs
63 Just j => j :: mapMaybe f xs
63 Just j => j :: mapMaybe f xs
65−--------------------------------------------------------------------------------
67−--------------------------------------------------------------------------------
69−instance Functor Maybe where
70− fmap f Nothing = Nothing
71− fmap f (Just j) = Just (f j)
73−instance Monad Maybe where
76− (>>=) Nothing m = Nothing
77− (>>=) (Just j) m = m j