[boost] Re: Re: Boost library inclusion: generic tree containers?

From: Thorsten Ottosen (nesotto_at_[hidden])
Date: 2005-02-24 10:54:47

"Joaquín Mª López Muñoz" <joaquin_at_[hidden]> wrote in message 
news:421DD6FC.A717DC5_at_tid.es...

Thorsten Ottosen ha escrito:

> "Justin Gottschlich" <jgottschlich_at_[hidden]> wrote in message

> I'm not sure I like the expression "trees as algorithms". I would like to 
> see
> different types of iterators which can then be used to implement algorithms.
>
> So I only see trees as containers.
>

|I agree with Thorste here. Thinking about the relation between a tree
|structure and its various iterators, maybe we can adopt a similar conceptual
|approach as Boost.MultiIndex: a tree container is the underyling data 
structure,
|on top of which several "indices" are provided with different iteration 
policies:
|
|typedef tree<element> tree_t;
|tree_t tr;
|
|tree_t::iterator<inorder>::type it1=tr.get<inorder>().begin; // inorder 
iteration
|tree_t::iterator<preorder>::type it2=tr.get<preorder>().begin; // preorder
|iteration
|
|// convertibility between different types of iterators
|it2=tr.project<preorder>(it1);

I'm not to keen on the idea that iterators are parameterized with an iteration 
policy.
It would be more natural just to have

tree_t::inorder_iterator i = tr.inorder_begin();
tree_t::preorder_iterator i2 = tr.preorder_begin();

This shouldn't prohibit conversion between the iterators AFAICT, but it will 
remove the
need for a lot of template stuff which is only there to make the stuff harder 
to use and to make
error messages harder to read.

br

-Thorsten