[Haskell-beginners] Error while using type and data constructor

[Nishant]

Hi,

I was writing some code for Tree.

1 : data Tree a = NULL | Node a (Tree a) (Tree a)   works fine. But,
2  : data Tree a = NULL | Tree a (Node a) Tree a does not work. GHCI says
Not in scope " type constructor or class 'Node'.

Why is 2 declaration not valid though second definition looks much more
closer to what a binary tree actually means ?


Regards
Nishant Verma
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