gistfile1.cpp

template<typename R>
struct call_with_proper_order_of_evaluation {
    template<typename F, typename... Args>
    call_with_proper_order_of_evaluation(F&& f, Args&&... args)
        : result(std::forward<F>(f)(std::forward<Args>(args)...)) { }

    R result;
};

template<typename... Args, typename F>
handle make_subroutine(F impl) {
    return handle(subroutine([impl = std::move(impl)] (auto arguments_begin, auto arguments_end) {
        if (static_cast<std::size_t>(std::distance(arguments_begin, arguments_end)) != sizeof...(Args)) {
            throw precondition_violation("invalid number of arguments passed");
        }
        call_with_proper_order_of_evaluation<handle> call{impl, arguments_begin++->template data<Args>()...};
        return call.result;
    }));
}