As long as you're making it seem like C / C++ code, but isn't, and will break if you treat it like C / C++ code, why not actually extend the syntax? Something

As long as you're making it seem like C / C++ code, but isn't, and will break if you treat it like C / C++ code, why not actually extend the syntax? Something like PY_CODE(<blah>), for instance. That way it won't compile unless you run it through the preprocessor.