tuples types

tt.cpp

#include <tuple>

// Macro to declare elements of an `enum class`
#define DEFINE_ENUM_TYPE(type, id) type = id,

// Declare currencies
#define CURRENCIES(code) \
  code(USD, 0) \
  code(EUR, 1)

#define CURRENCY_TO_STRING(type, id) case currency::type: return #type;

enum class currency {
  CURRENCIES(DEFINE_ENUM_TYPE)
};

auto currency_to_string(currency c) {
  switch (c) {
    CURRENCIES(CURRENCY_TO_STRING)
  }
  return "";
}

// Declare message types
#define MSG_TYPES(code) \
  code(heartbeat, 0) \
  code(reject, 4)

#define MSG_TYPE_TO_STRING(type, id) case msg_type::type: return #type;

enum class msg_type {
  MSG_TYPES(DEFINE_ENUM_TYPE)
};

auto msg_type_to_string(msg_type m) {
  switch (m) {
    MSG_TYPES(MSG_TYPE_TO_STRING)
  }
  return "";
}

int main() {
  std::tuple<currency, msg_type> t = {currency::EUR, msg_type::reject};
  printf("currency: %s\n", currency_to_string(std::get<currency>(t)));
}