...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::accumulator_base
// In header: <boost/accumulators/framework/accumulator_base.hpp> struct accumulator_base { // types typedef mpl::false_ is_droppable; // public member functions unspecified operator()(dont_care) ; unspecified add_ref(dont_care) ; unspecified drop(dont_care) ; unspecified on_drop(dont_care) ; };