At Sun, 17 Oct 2010 14:34:48 -0400, Matt Calabrese wrote:
On Sun, Oct 17, 2010 at 5:34 AM, David Abrahams <dave@boostpro.com> wrote:
I'm all for embarrassing the designers of the language feature by building macros that work better :-) Maybe, like BOOST_FOREACH, they'll turn back into language features one day.
Heh, perhaps in C++3x (pending it doesn't roll over to 4x).
When I added the "requires" feature I looked up how "requires" would have worked in C++0x so that I could try to mimic it as closely as possible. In doing this, one thing I noticed was that you had to put your "requires" immediately after template< /**/ > and before the function name and return type. The downside of this is that it implies that you can't refer to your arguments in the predicate (I.E. sizeof( left + right ) or something similar)! Not that such uses would have been very common anyway
Right, you should be writing your requirements in terms of concepts if you have that facility.
but BOOST_AUTO_FUNCTION doesn't suffer from that problem at all since "requires" comes after the parameter list.
BTW, seems like you're close enough; it's probably time to integrate concept support for a future BCCL. -- Dave Abrahams BoostPro Computing http://www.boostpro.com