Re: Variable objects and STL containers

Nick Roberts
2008-02-17T19:55:24Z

> > Actually it looks doable for lists, maps etc if the children of a variable
> > object were stored as a list rather than a vector. This is so that a new
> > child can be added, or an old one deleted, at any point in the list.
> >
> > Ironically, the children were previously stored in a linked list and I
> > guess vectors were used because Nathan Sidwell has created an API in C for
> > them. There doesn't appear to be a similar API for lists, but since they
> > are more flexible, would it be possible to revert var->children to a
> > linked list?
>
> I'm afraid I don't see any such flexibility. Can you clarify? The vectors
> were used because they allowed to eliminate lots of custom list handling
> code, and I'm reluctant to go back.

I can understand that you are reluctant to go back but I'm surprised that you
don't see the convenience. Until now the number of children has been fixed, so
vectors are probably a natural choice. With STL containers the number changes
and and it becomes advantageous to use lists. Taking maps, for example, they
appear to be stored as binary trees and GDB can traverse the tree (inorder) to
examine all the nodes. When it finds a new one, it needs to create a new child
*at that point* in the sequence of children. A vector can't do that. It can
only add or remove them at the end, so a list must be used.

--
Nick http://www.inet.net.nz/~nickrob