...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::transform::result<This(Expr, State, Data)>
// In header: <boost/proto/transform/impl.hpp> template<typename This, typename Expr, typename State, typename Data> struct result<This(Expr, State, Data)> { // types typedef typename PrimitiveTransform::template impl< Expr, State, Data >::result_type type; };