Kuba Ober wrote:

> I think that the only real solution is that the tree must know of its
> iterators and adjust them if tree structure changes.
> 
> I presume that it should call into existence a proper tree base classes
> for leafs and nodes. I wonder if they exist in the current design. [No
> time to look at the code, sorry :( ]
> 
> Essentially, it should be tree's leaves and nodes which should be able to
> know which cursors point at them. Since there will be probably very few
> cursors in existence at any given time (say 10 or something of that
> order), it's conceiveable that:
> a) a tree element, upon each change, will look through the "global" list
> of cursors to see which cursors point to it
> b) it will adjust them per the pending change
> 
> That also makes cursors invariants between changes to either tree elements
> or cursor position, and makes all cursors automatically always valid no
> matter what.
> 
> Does it make any sense? Is that the direction you are going? Am I talking
> rubbish? I'm just a bystander and overseer, but I would like to know what
> pattern are you converging to in the long term.

It has been already discussed in
http://marc.theaimsgroup.com/?t=105393027500002&r=1&w=2
(and before, IIRC).
The outcome: maybe, but let's try to stick to par "id"s if it is enough. And
no, I don't think it is enough for when we have multiple BVs, but that can
be introduced later.

Regards, Alfredo


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