gistfile1.hs

import Control.Monad

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

(<<) EmptyTree value = Node value EmptyTree EmptyTree
(<<) (Node value left right) newValue = if newValue < value
    then Node value (left << newValue) right
    else Node value left (right << newValue)

toArray EmptyTree = []
toArray (Node value left right) = toArray left ++ value : toArray right

printTree :: (Show t) => Tree t -> IO ()
printTree tree = mapM_ print (toArray tree)