...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
boost::yap::expression_function
// In header: <boost/yap/algorithm.hpp> template<typename Expr> struct expression_function { // public member functions template<typename... U> constexpr decltype(auto) operator()(U &&...); // public data members Expr expr; };