Method push

include/sol/stack_reference.hpp:72–78

		stateless_stack_reference& operator=(const stateless_stack_reference&) noexcept = default;

		int push(lua_State* L_) const noexcept {
#if SOL_IS_ON(SOL_SAFE_STACK_CHECK)
			luaL_checkstack(L_, 1, "not enough Lua stack space to push a single reference value");
#endif // make sure stack doesn't overflow
			lua_pushvalue(L_, m_index);
			return 1;
		}

		void pop(lua_State* L_, int pop_count = 1) const noexcept {
			lua_pop(L_, pop_count);