Re: [Haskell-cafe] Monad for binary tree data structure

2011/7/23 Александр :

Hello,

I built binary tree with:

data Tree a = Empty               | Node a (Tree a) (Tree a)               deriving (Eq, Ord, Read, Show) How can i make Monad type class instance for this tree? And can i make it on not?

i try:

instance Monad Tree where     return x = Node x Empty Empty     Empty >>= f = Empty     (Node x Empty Empty) >>= f = f x

1) Do you really need a Monad instance for this? 2) One possibility is just have it being (Node x _ _) >>= f = f x -- Ivan Lazar Miljenovic Ivan.Miljenovic@gmail.com IvanMiljenovic.wordpress.com