On Fri, 12 Aug 2011 15:54:53 -0400, Ellery Newcomer
<ellery-newco...@utulsa.edu> wrote:
in std.container, the stable* container functions advocate that they do
not invalidate the ranges of their containers. What does it mean to
invalidate a range?
Say for example, you are iterating a red black tree, and your current
"front" points at a certain node. Then that node is removed from the
tree. That range is now invalid, because the node it points to is not
valid.
What happens when you use an invalidated range? Well, we could implement
something that throws an exception, but that's an efficiency problem. I
contemplated doing this for debug mode in dcollections, I probably still
will.
Another example of an invalidated range, let's say you have a hash map.
The range has a start and a finish, with the finish being iterated after
the start. If you add a node, it could cause a rehash, which could
potentially put the finish *before* the start!
However, the same hash implementation could potentially define a stable
add, which is guaranteed not to rehash the map, even when it exceeds the
rehash threshold :)
-Steve
