data List e = Nil | Cons e (List e) data Bin e = Leaf | Branch (Bin e) e (Bin e)
Knotenreihenfolgen
preorder :: forall e . Bin e -> List e preorder t = case t of ...
inorder, postorder
False = links,
True = rechts)
get :: Tree e -> List Bool -> Maybe e
positions :: Tree e -> List (List Bool)