lab06: init

lab06/functors.lhs

@@ -0,0 +1,21 @@
+> data Tree v =
+>     Empty
+>   | Node v (Tree v) (Tree v)
+>   deriving (Show)
+
+The findT method shows how we may search through the tree to find a value.
+
+> findT :: Ord v => v -> Tree v -> Maybe v
+> findT _ Empty = Nothing
+> findT v (Node val left right) =
+>   if val == v then
+>     Just val
+>   else if v < val then
+>     findT v left
+>   else
+>     findT v right
+
+Your job is to add support for fmap to this tree, so that the call to fmap below works:
+
+> main = print $ fmap (+1) (Node 3 (Node 1 Empty Empty) (Node 7 (Node 4 Empty Empty) Empty))
+