On Mon, 08 Mar 2010 13:21:14 -0500, Andrei Alexandrescu
<[email protected]> wrote:
Steven Schveighoffer wrote:
Hm... this seems to be a different problem than I originally was
thinking about. So in essence, you want a set of "safe" functions that
will not adversely affect a range you are using to iterate with?
That's the idea. Any documentation of STL containers specifies whether
iterators are invalidated or not by a primitive. The plan is to simply
define a nomenclature (i.e. "softXxx") for primitives that don't
invalidate iterators. That moves the documentation into the name of the
function.
What I meant was, your example only focuses on the iterator being advanced
in the loop. Another iterator might be invalidated that is not used in
the remove function. Was that the intent?
BTW, I solved this problem (removing while iterating) in a much
better/simpler way in dcollections.
Do tell!
I created a method purge, which is used as an opApply in a foreach loop
like so:
foreach(ref erase, v; &container.purge)
{
erase = should_delete_this_guy;
}
One nifty thing about this, purging an entire collection is an O(n) up to
O(nlgn) operation, whereas purging a vector as you wrote is an O(n*n)
operation.
I found that one of the biggest reasons I liked about STL's containers
over others that I've used is the ability to remove elements from the
container while iterating. Java allows this also, but no foreach, and it
doesn't make optimizations, since the iterator is in charge of removal,
not the container itself.
-Steve
