6 May
2017
6 May
'17
7:04 p.m.
On 2017-05-06 20:38, David Kraeutmann wrote:
The only lawful instance I can think of is: instance Functor (FunPB a) where fmap f (FunPB g) = FunPB $ \k -> let (a,b) = g k in (a, fmap f b)
which is fairly straightforward IMO. And because it's closer to the original style:
fmap f = FunPB .((.)((<$>).(<$>)$f)). runFunPB Now it's STARRING INTO YOU SOUL. And it's also so much easier to read.