...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
boost::proto::functional::unpack_expr::result<This(Sequence)>
// In header: <boost/proto/make_expr.hpp> template<typename This, typename Sequence> struct result<This(Sequence)> : proto::result_of::unpack_expr< Tag, Domain, typename boost::remove_reference< Sequence >::type > { };