Tobias Schwinger wrote:
Peter Dimov wrote:
Stjepan Rajko wrote:
[comes to a screeching halt from changing code]
Yep. :-)
Sorry for the false alarm!
I'm still not entirely on very sure footing when it comes to rvalues and lvalues, so can I bother you with a practical clarification?
So, if I have, say, a function object with operator()(int &), I should specify result<F(int &)>, (but maybe if I have operator()(const int &), or operator()(int), I can specify result<F(int)>?)
If you have operator()( int& ), you need result<F(int&)>. If you have operator()( int ), you need both result<F(int)> and result<F(int&)> because your operator() can take either an lvalue or an rvalue.
We'd also need 'int const &' (given we don't just provide 'result_type' or deduce whatever it is), right?
And bool, and char, and double, and so on; every argument type that can be passed to operator(). It's not practical to enumerate everything. But to answer your question, yes, a const lvalue of type int is a valid argument and needs to be supported by your specialization/result.