Specifically for my application, you (as maintainer of boost.Iterator?) would have to change boost::transform_iterator/filter_iterator and Joaquin multi_index_container. If we can agree on that, I will change the code to CRTP.
I am willing to consider such changes.
CRTP it is.
How is that clever? It follows the same pattern as the one for a custom swap:
using std::swap; CustomType tA, tB; swap( tA, tB );
What do you propose instead?
I think if you want to call lower_bound in the most efficient way, it should be possible to do so with qualification. If the algorithm in std:: isn't sufficiently "hookable," one should create a different one that is. The universe of names to be found by ADL should be limited to fundamental operations like swap, since ADL reserves names "globally."
Hmmm. I see it this way: std::lower_bound has well-defined semantics, and we don't change them. We merely provide an implementation for a particular iterator. If that would be the end of the story, you would probably agree that ADL is the way to go and using std::lower_bound; lowerbound(customIt, customIt, ...); // unqualified is the right way to call the custom lower_bound. Now it happens that for some class of iterators, lower_bound/... can be implemented on top of partition_point. I consider this an implementation detail, which you specify by deriving this iterator from a particular base class. I think the situation is really the same as in Boost.Operators that implements operator+ via operator+=. -- Dr. Arno Schoedl · aschoedl@think-cell.com Technical Director think-cell Software GmbH · Invalidenstr. 34 · 10115 Berlin, Germany http://www.think-cell.com · phone +49-30-666473-10 · toll-free (US) +1-800-891-8091 Directors: Dr. Markus Hannebauer, Dr. Arno Schoedl · Amtsgericht Charlottenburg, HRB 85229