...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
boost::nfp::param_type — param_type<Params,Keyword,Default>::type is the type of the parameter corresponding to the Keyword (if parameter is present) or Default
// In header: <boost/test/utils/named_params.hpp> template<typename NP, typename Keyword, typename DefaultType = void> struct param_type : public mpl::if_< is_same< NP::id, Keyword::id >::type, remove_cv< NP::data_type >::type, void > { };