12 Apr
2011
12 Apr
'11
3:13 p.m.
On Tue, 12 Apr 2011, Edward Amsden wrote:
I am trying as an experiment to write something as follows:
data Wrapper a b where Pure :: (a -> b) -> Wrapper a b Nullable :: (Maybe a -> b) -> Wrapper a b
class Liftable a b where liftTo :: (b -> c) -> a b c
instance Liftable Wrapper a where liftTo = Pure
Would it be ok, to erm wrap 'a', say newtype Generic a = Generic a instance Liftable Wrapper (Generic a) where liftTo = ...
instance Liftable Wrapper (Maybe a) where liftTo = Nullable