text: #define SOL_CHECK_ARGUMENTS
  #include <sol.hpp>
  
  #include <iostream>
  #include <cassert>
  
  struct test {
  	static int muh_variable;
  };
  int test::muh_variable = 25;
  
  
  int main() {
  	std::cout << "=== static_variables example ===" << std::endl;
  
  	sol::state lua;
  	lua.open_libraries();
  	lua.new_usertype<test>("test",
  		"direct", sol::var(2),
  		"global", sol::var(test::muh_variable),
  		"ref_global", sol::var(std::ref(test::muh_variable))
  	);
  
  	int direct_value = lua["test"]["direct"];
  	// direct_value == 2
  	assert(direct_value == 2);
  	std::cout << "direct_value: " << direct_value << std::endl;
  
  	int global = lua["test"]["global"];
  	int global2 = lua["test"]["ref_global"];
  	// global == 25
  	// global2 == 25
  	assert(global == 25);
  	assert(global2 == 25);
  
  	std::cout << "First round of values --" << std::endl;
  	std::cout << global << std::endl;
  	std::cout << global2 << std::endl;
  
  	test::muh_variable = 542;
  
  	global = lua["test"]["global"];
  	// global == 25
  	// global is its own memory: was passed by value
  
  	global2 = lua["test"]["ref_global"];
  	// global2 == 542
  	// global2 was passed through std::ref
  	// global2 holds a reference to muh_variable
  	// if muh_variable goes out of scope or is deleted
  	// problems could arise, so be careful!
  
  	assert(global == 25);
  	assert(global2 == 542);
  
  	std::cout << "Second round of values --" << std::endl;
  	std::cout << "global : " << global << std::endl;
  	std::cout << "global2: " << global2 << std::endl;
  	std::cout << std::endl;
  
  	return 0;
  }
  