Re: [Haskell-beginners] Maybe a -> Maybe b

as an exercise, you can try to figure out the implementation

.. time is up :-P Here is an answer for slightly more generic Proxy and f: data Proxy a = Proxy a exProxy::Functor f => f (Proxy a) -> f a exProxy = (un1 <$>) where un1 (Proxy a1) = a1 ​