[Haskell-beginners] Empty or Tree?

[Aditya Manthramurthy]

I think this is because "Tree" is a data type and not a data constructor.
According to your definition of Tree, Empty and Node are the constructors.

Node a (Node b (Node c Empty Empty) (Node d Empty Empty)) (Node e (Node f
Empty Empty) (Node g Empty Empty))

is a valid tree if a, b, c, d, e, f, g are integers.

Hope this helps.

--
Aditya.

On 10 March 2012 15:58, bahadýr altan <doaltan at yahoo.co.uk> wrote:

> Hello everyone. I'm trying to write a code which works on binary trees.
> When I write code like this  with a tree with empty nodes :
>
> data Tree  =  Empty | Node  Integer Tree Tree
>
> function Node a (Node b Empty Empty)  (Node c Empty Empty)
>
> it works fine.
> But when I try to create a more generic code like this  which could  work
> with trees who don't have empty nodes in grandchild level :
>
> function Node a (Node b Tree Tree)  (Node c Tree Tree )
>
> I get this error : Undefined data constructor "Tree"
>
> Can you help me with creating more generic code please?
> Thanks
>
>
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