@@ -106,6 +106,10 @@ instance Functor Maybe where
106 fmap f (Just x) = Just (f x)
106 fmap f (Just x) = Just (f x)
107 fmap f Nothing = Nothing
107 fmap f Nothing = Nothing
109+instance Functor (Either e) where
110+ fmap f (Left l) = Left l
111+ fmap f (Right r) = Right (f r)
109instance Functor List where
113instance Functor List where
110 fmap = map
114 fmap = map