...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
boost::accumulators::tag::as_droppable<droppable< Feature >>
// In header: <boost/accumulators/framework/accumulators/droppable_accumulator.hpp> template<typename Feature> struct as_droppable<droppable< Feature >> { // types typedef droppable< Feature > type; };