On 18.04.2012 10:20, Jeffrey Lee Hellrung, Jr. wrote:
For better or for worse, the present logic in iterator_facade is strictly (more or less) correct given the C++03 iterator requirements, but I just looked up the N3290 draft of C++11 and it appears that any requirements that *i return a real reference have been dropped, thus allowing for proxy references in all iterator categories. (a) Am I interpreting the C++11 iterator requirements correctly?
I'm afraid not. I can only quote N3376 (the first draft of C++1y) right now, but it says in the requirements for forward iterators (24.2.5p1): "if X is a mutable iterator, /reference/ is a reference to T; if X is a const iterator, /reference/ is a reference to const T," where /reference/ refers to iterator_traits<X>::reference. And of course the primary Iterator requirements specify that *r returns iterator_traits<X>::reference. The change in iterator requirements was supposed to piggy-back on concepts; when they were removed, so were the iterator changes. They basically haven't changed since C++03. Sebastian