...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
boost::proto::functional::second::result<This(Pair)>
// In header: <boost/proto/functional/std/utility.hpp> template<typename This, typename Pair> struct result<This(Pair)> { // types typedef typename Pair::second_type type; };