[Haskell-cafe] Monad for binary tree data structure

[Ivan Lazar Miljenovic]

2011/7/23 Александр <kommunist1917 at mail.ru>:
> 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 at gmail.com
IvanMiljenovic.wordpress.com