Re: [Haskell-beginners] Help with a data type declaration

It just stores a 'b' on every branch and an 'a' on every leaf. I'm not sure what you'd use it for, but there's nothing wrong with it. On Tue, Sep 29, 2015 at 11:10 AM, emacstheviking wrote:

Is the definition of Branch correct though, shouldn't it be Branch (Tree a b) (Tree a b) ...?

On 29 September 2015 at 16:10, emacstheviking wrote:

...

a = left b = right

That would at least make the sentiment clearer.

On 29 September 2015 at 15:10, wrote:

...

How can I interpret the following data type declaration? The book where I am studying (and other sources I have read as well) only show more simple examples. This is what I can say about it:

* "Tree" is the name of the new type. * "Branch" and "Leaf" are the type constructors. * What is "a" and "b"? * It seems to me that this type is kind of "recursively" defined but I do not know exactly.

data Tree a b = Branch b (Tree a b) (Tree a b) | Leaf a

I will very much appreciate your feedback.

Regards, JAMB _______________________________________________ Beginners mailing list Beginners@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners

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