Test Pastie

flatten.hs

data BiTree a = Leaf a | BiTree a (BiTree a) (BiTree a) deriving Show

{-flatten :: BiTree a -> [a]-}
{-flatten (BiTree v l r)= [v] ++ flatten l ++ flatten r-}
{-flatten (Leaf v)		= [v]-}

flatten' :: BiTree a -> [a] -> [a]
flatten' (Leaf v) res		= v:res
flatten' (BiTree v l r) res	= v:flatten' l (flatten' r res)

flatten :: BiTree a -> [a]
flatten t = flatten' t []

t = (BiTree 0.5 (Leaf 1.0) (BiTree 0.2 (Leaf 2.0) (Leaf 3.0)))

main = putStrLn ( "Tree: " ++ show t ) >> putStrLn ( "Flattened: " ++ show (flatten t) )