Date: Wed, 18 Sep 2013 20:33:31 -0300 From: kaballo86@hotmail.com

The following snippet fails to compile (tested with 1.54.0 and trunk, several compilers),

#include #include #include

int main() { using namespace boost::mpl; static_assert(and_::value, "U KID?"); //this one fires static_assert(or_::value, "U KID?"); //this one is ok }

This issue actually showed up in a variadic template scenario. Is this a bug? I feel like I'm doing something really wrong...

Not to miss the important part, there is a bug. (A single argument for "and" or "or" should return itself.) Have you put it on our Trac system? You should probably mention this thread; search on one of the mailing list archive sites to find the first message so you can add its link to the bug report. Daryle W.

On 09/18/13 18:33, Agustín K-ballo Bergé wrote:

The following snippet fails to compile (tested with 1.54.0 and trunk, several compilers),

#include #include #include

int main() { using namespace boost::mpl; static_assert(and_::value, "U KID?"); //this one fires static_assert(or_::value, "U KID?"); //this one is ok }

This issue actually showed up in a variadic template scenario. Is this a bug? I feel like I'm doing something really wrong...

I guess one may not call `and_` with less than two arguments. If that's the case, it would be helpful if it would be impossible to instantiate it with a single argument.

Regards,

There's a variadic mpl::and_ and mpl::or_ which I think solves this problem. However, I seriously doubt it would compile as fast because, my impression is that the standard boost mpl spent a lot of effort using the preprocessor to speed compile times, and the variadic versions here: http://svn.boost.org/svn/boost/sandbox/variadic_templates/boost/mpl/ were not coded with compile speed in mind :( -regards Larry