Re: [boost] [typeof][implementation]why not use decltype or conditional expr?

paul Fultz wrote:

...

And if decltype not available, why couldn't it use the conditional expression method described here:

http://www.artima.com/cppsource/foreach2.html

Actually, the rvalue detection techniques in the article could be used to create a better decltype emulation on older compilers. I use this here:

https://github.com/pfultz2/Zelda/blob/master/zelda/typeof.h

Its a macro called ZELDA_XTYPEOF, which in C++11 is the equivalent of decltype(()) with double parenthesis. On older compilers, it will bind to a reference, unless its an rvalue which it will not have a reference.

On C++03-compliant compilers, you cannot use Boost.Foreach's technique to detect rvalueness for classes with a template conversion operator. Regards, Michel