On Apr 3, 2012, at 12:23 PM, Dave Abrahams wrote:
on Sun Apr 01 2012, Howard Hinnant <howard.hinnant-AT-gmail.com> wrote:
On Mar 31, 2012, at 10:12 PM, Dave Abrahams wrote:
Hi All,
I am on the C++Now 2012 schedule giving a talk on metaprogramming in C++11, which is really just supposed to be an overview of the state of the art. I am just at the beginnings of my research for this presentation, having learned a few things and done a few experiments, and it seemed to me foolish not to ask the Boost community for its insights. I'm sure y'all have come up with many neat tricks and techniques. If you'd care to share them here, that would be much appreciated.
The fact that noexcept(expression) is a compile-time bool is like unwrapping a shiny new toy on your birthday. :-)
That's lovely, but... exactly how does noexcept play into the metaprogramming picture?
For example, I used it to create an is_nothrow_swappable<A> trait (http://llvm.org/svn/llvm-project/libcxx/trunk/include/type_traits) so that I could write: struct B { A a; }; void swap(B& x, B& y) noexcept(__is_nothrow_swappable<A>::value) { swap(x.a, y.a); } instead of: using std::swap; void swap(B& x, B& y) noexcept( noexcept( swap(declval<A&>(), declval<A&>()))) { swap(x.a, y.a); } The latter gets very tedious when B has several members and/or bases. Howard