...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::compose_generators::result<This(Expr)>
// In header: <boost/proto/generate.hpp> template<typename This, typename Expr> struct result<This(Expr)> : boost::result_of< Second(typename boost::result_of<First(Expr)>::type) > { };