struct A {
  virtual void foo() = 0;
};

void do_something(A* a) {
  a->foo();
}

class 'MyA' (A)
....
function MyA:foo()
  print('hi')
end

... // somehow create an instance of MyA class and named myA
    // How?
    // Maybe the result of a call to "MyA()"?

do_something(myA);

// C++
struct LuaA : public A
{
  LuaA(const std::string &luacode)
    : myLuaHandler(luacode)
  {
  }

  virtual void foo()
  {
    myLuaHandler.call("MyA:foo()");
  }
}

virtual void f(int a)
{
    call<void>("f", a);
}