on Tue Jan 29 2013, Paul Smith <pl.smith.mail-AT-gmail.com> wrote:
On Tue, Jan 29, 2013 at 7:25 PM, Jeffrey Lee Hellrung, Jr. <jeffrey.hellrung@gmail.com> wrote:
This discussion might be facilitated if Joel et al (sorry Joel, I don't mean to pick on you, I just mean the group arguing for introducing this "singular" post-move state) simply said "yes, we understand we're making a breaking change (by possibly introducing an additional state to variant that violates the never-empty guarantee), but we still think it's the most practical approach to introduce efficient move semantics to variant". I can jive with that but I think Paul's concerned that you (again, as a representative of the platform you're taking) don't appreciate that this is a breaking change to variant.
I think this is about a little more than that, even though to be honest, I'm not entirely sure what's the dispute is about too. I think it's closer to what Edward Diener said:
The main issue seems to be simply this: are guarantees ( invariants ) for an object of a class meant to cover moved from objects of that class?
I don't think that question should really even be on the table. If "invariant" and "guarantee" are to have any useful meaning, the answer must be "yes." -- Dave Abrahams BoostPro Computing Software Development Training http://www.boostpro.com Clang/LLVM/EDG Compilers C++ Boost