On 26 Feb 2010, at 20:11, DE wrote:
on 26.02.2010 at 21:27 Jeffrey Hellrung wrote :
Yes, the type of an rvalue can be const-qualified, but the current mechanism cannot distinguish between a const-qualified rvalue and a const-qualified lvalue. So only returning by non-const value will work.
For a simple demonstration of the basic mechanism (untested, so not sure if it will compile, but it should give the basic idea) [code here] oh now i get it! i didn't realize there are operator rv<T>& and its const counterpart hidden behind the macros thanks for your effort explaining this
I don't have any simpler solutions, only a spectrum of solutions to select the best set of tradeoffs for a given situation. Which, in some sense, is more complicated. so summing it all up i say that this solution is far too tricky to be useful no offence it seems to me too restrictive and too incomplete the infrastructure is too complicated on the other hand i guess forcing users to return something like rv<t> from functions like this
rv<my_type> foo();
is not an option
another question arises: who is the target audience (aka users) of this lib?
I use this lib myself, as it implements a significant subset of "true rvalue references" from C++0x. Using this library, and some care, we can write optimal code for new C++0x compilers, while maintaining support for older C++03 compilers as well. Chris