static std::uint32_t to(state_t &state, const map_t &map_val)
{
::lua_createtable(state, (int)map_val.size(), (int)map_val.size());
std::for_each(map_val.cbegin(), map_val.cend(),
[&state](const typename map_t::value_type &val)
{
convertion_t<typename map_t::key_type>::to(state, val.first);
convertion_t<typename map_t::mapped_type>::to(state, val.second);
::lua_settable(state, -3);
});
return map_val.size() == 0 ? 0 : 1;
}
const_iterator cbegin() const noexcept { return map_index_n.cbegin(); }