Re: [Haskell-cafe] Re: Why is this strict in its arguments?

On Dec 5, 2007 12:16 AM, Aaron Denney wrote:

On 2007-12-04, Paulo J. Matos wrote:

...

Hello all,

As you might have possibly read in some previous blog posts: http://users.ecs.soton.ac.uk/pocm06r/fpsig/?p=10 http://users.ecs.soton.ac.uk/pocm06r/fpsig/?p=11

we (the FPSIG group) defined: data BTree a = Leaf a | Branch (BTree a) a (BTree a)

Totally avoiding your question, but I'm curious as to why you deliberately exclude empty trees.

Come to think of it, how can you represent a tree with two elements?

Good question. I think we were just trying to define a tree in the meeting and everyone agreed on this representation.

Wouldn't

...

data BTree a = Empty | Branch (BTree a) a (BTree a)

be better?

Possibly :) I think that at the time nobody really cared about empty trees! But for a really application we would have had to define them probably. Now thinking about it, it seems like defining lists without Null, strange, isn't it?

-- Aaron Denney -><-

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-- Paulo Jorge Matos - pocm at soton.ac.uk http://www.personal.soton.ac.uk/pocm PhD Student @ ECS University of Southampton, UK