...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::_byref::result<This(T)>
// In header: <boost/proto/transform/arg.hpp> template<typename This, typename T> struct result<This(T)> { // types typedef boost::reference_wrapper< T const > const type; };