meta-serdes.cxx

#include <iostream>
#include <sstream>
#include <string>
#include <tuple>
#include <array>
#include <experimental/array>

namespace std { using std::experimental::make_array; }

#include <boost/preprocessor.hpp>

#define EXPOSE_MEMBERS_Q(M_ignore0, M_ignore1, M_member)        \
    BOOST_PP_STRINGIZE(M_member)

#define EXPOSE_MEMBERS(...)                                     \
    auto members() {                                            \
      return std::forward_as_tuple(__VA_ARGS__);                \
    }                                                           \
    auto members() const {                                      \
      return std::forward_as_tuple(__VA_ARGS__);                \
    }                                                           \
    static constexpr auto names() {                             \
      return std::make_array(                                   \
        BOOST_PP_LIST_ENUM(                                     \
          BOOST_PP_LIST_TRANSFORM(                              \
            EXPOSE_MEMBERS_Q, @,                                \
            BOOST_PP_VARIADIC_TO_LIST(__VA_ARGS__))));          \
    }

template <typename T>
std::ostream& operator << (std::ostream& os, T const& obj) {
  using std::operator <<;

  std::apply([&os](auto const& names,
                   auto const& fst,
                   auto const&... rest) {
    unsigned int i = 0;
    os << names[i] << '=' << fst;
    ((os << ", " << names[++i] << '=' << rest), ...);
  }, std::tuple_cat(std::make_tuple(obj.names()),
                    obj.members()));
  return os;
}

template <typename T>
std::istream& operator >> (std::istream& is, T& obj) {
  using std::operator >>;

  std::apply([&is](auto&... members) {
    (is >> ... >> members);
  }, obj.members());
  return is;
}

struct employee {
  std::string name;
  int salary;

  EXPOSE_MEMBERS(name, salary);
};

int main(int, char**) {
    employee e{"Steve Jobs", 1};

    std::cout << e << std::endl;
    
    std::string input = "Bill-Gates 100";
    std::istringstream ss{input};
    ss >> e;
    
    std::cout << e << std::endl;
}