Hello David, gruenedd@idmt.fraunhofer.de ha escrito:

Hello,

What is the status of key swapping, issued here[1]? Do you see a chance to have this included sometime? :]

Nothing like that has been included in Boost 1.34, and I decided to finally not implement the idea because: * It can be simulated externally (admittedly, not in an optimal fashion). * I don't see as a commonly wanted feature. * It implies weird semantics: swapping keys can result in collisions arising in other indices. Consider for instance: multi_index_container< std::pair<int,int>, indexed_by< ordered_unique<member<std::pair<int,int>,int,&std::pair<int,int>::first> >, ordered_unique<identity<std::pair<int,int> > >

c;

c.insert(std::make_pair(0,1)); c.insert(std::make_pair(1,0)); c.insert(std::make_pair(1,1)); c.swap_keys(c.begin(),++c.begin()); // would yield a duplicate element (1,1) Not that this cannot be handled, but it implies that a possible outcome of swap_keys() is that both elements get deleted or the operation rolled back, which is IMHO a little surprising to the unadvertent user. I'm sorry the answer to your proposal is negative.

Best Regards, David

[1] http://lists.boost.org/boost-users/2005/04/11223.php

On another issue, you might be interested to know that the problem you brought forward in http://lists.boost.org/Archives/boost/2005/02/80589.php has been solved in 1.34, and the very sample snippet you provided then now compiles and works cleanly. The solution does not follow your proposed approach, but uses boost::disable_if<> instead. More info at http://boost-consulting.com/boost/libs/multi_index/doc/release_notes.html#bo... (third bullet). Best regards, Joaquín M López Muñoz Telefónica, Investigación y Desarrollo