Haskell Bin Tree to List

gistfile1.txt

module Main where

data Tree a = Empty | Node a (Tree a) (Tree a)

tree :: Tree Int
tree = Node 4 (Node 2 (Node 1 Empty Empty) (Node 3 Empty Empty)) (Node 6 (Node 5 Empty Empty) (Node 7 Empty Empty))

toList :: Tree a -> [a]
toList root = go root []
    where go :: Tree a -> [a] -> [a]
          go Empty xs = xs
          go (Node v l r) xs = go l $ v : go r xs

main :: IO ()
main = do
  print $ toList tree