...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
boost::icl::map::on_total_absorbable
// In header: <boost/icl/map.hpp> template<typename Type, bool is_total, bool absorbs_identities> struct on_total_absorbable { };