...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::partial_absorber
// In header: <boost/icl/map.hpp> struct partial_absorber { enum @3 { absorbs_identities = = true }; enum @4 { is_total = = false }; };