1 Aug
2007
1 Aug
'07
3:58 a.m.
The code in "Bananas in Space: Extending Fold and Unfold to Exponential Types" http://citeseer.ist.psu.edu/293490.html mirror: http://www.cs.nott.ac.uk/~gmh/bananas.pdf uses Gofer, and has examples such as data Rec f = In (f (Rec f)) type P f a = f (Rec f, a) mapP :: Functor f => (a -> b) -> P f a -> P f b mapP g = fmap (\(x,a) -> (x, g a)) instance Functor f => Functor (P f) where fmap = mapP Why did Gofer have this power while Haskell does not? Jim