--Matthew Larson Exercise 9.1 10/21/2019
--Functor.hs

import Prelude

data BinaryTree a
        = EmptyTree
        | Node a (BinaryTree a) (BinaryTree a)
        deriving (Show)

instance Functor (BinaryTree) where
  fmap f EmptyTree = EmptyTree
  fmap f (Node a (left)(right)) = Node (f a) (fmap f left ) (fmap f right)

tree :: BinaryTree Integer
tree = Node 3
        (Node 1
            (Node 0 EmptyTree EmptyTree)
            (Node 2 EmptyTree EmptyTree))
        (Node 5
            (Node 4 EmptyTree EmptyTree)
            (Node 6 EmptyTree EmptyTree))

--Exercise 9.3

 -- :t fmap :: Functor f => (a -> b) -> (c -> a) -> c -> b