Fernando Cacciola wrote:
Maybe boost::reference_wrapper can be used internally to wrap reference types and solve this issue.
How?
I was suggesting the use of reference_wrapper to avoid singling out reference types everywhere in the code. The new assignment operators might just work. Anyway, I haven't tested any of this so...
We're not talking about an implementation problem here; this is about the "correct" behaviour and whether is ok to change to it given the potential impact on user programs.
I see. In that case, please disregard my previous suggestion... I'll make a new one, hopefully more helpful ;) I suggest you document how users may workaround this issue in their code using boost::reference_wrapper/ref/cref. Here's a small snippet you can use. #include <boost/optional.hpp> #include <boost/none.hpp> #include <boost/ref.hpp> int main() { int a = 32; int b = 1279; boost::reference_wrapper<int> ra(a); boost::optional<boost::reference_wrapper<int> > orw1, // default constructor orw2(boost::none), // none_t constructor orw3(ra), // value constructor orw4(boost::ref(a)); // make reference boost::optional<int &> ori1(orw1), ori2(orw2), ori3(orw3.get()); orw1 = boost::ref(b); } Best regards, João