...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::child_c::result<This(Expr)>
// In header: <boost/proto/traits.hpp> template<typename This, typename Expr> struct result<This(Expr)> : proto::result_of::child_c< Expr, N > { };