data Tree a = Leaf | Node { key :: a , colour :: Colour , left :: Tree a , right :: Tree a } {-! for Tree derive: Haskell2Xml !-}Präprozessor
DrIFT
erzeugt daraus Quelltext
(Instanz für Interface)
class Haskell2Xml a where toXml :: a -> Document fromXml :: Document -> a