fp2/week2/mart/oldold/old/Map.icl

   1 implementation module Map
   2
   3 //import BinTree
   4 import StdMaybe
   5 import StdList
   6
   7 class Map c :: (a -> b) (c a) -> c b
   8
   9 instance Map [] where
  10         Map f [] = []
  11         Map f [x:xs] = [f x: Map f xs]
  12
  13 instance Map Maybe where
  14         Map f Nothing = Nothing
  15         Map f (Just x) = Just (f x)
  16
  17 //instance Map Tree  where
  18 //      Map f Leaf = Leaf
  19 //      Map f (Node x l r) = Node (f x) (mapTree f l) (mapTree f r)