Okay, finally found some time to provide you with a fully annotated example of your original ask here, assuming you wanted to transform the arguments passed to

Okay, finally found some time to provide you with a fully annotated example of your original ask here, assuming you wanted to transform the arguments passed to F into IDs, and the arguments passed to G into strings (as seemed to be the case from the rest of the thread). https://c.godbolt.org/z/6zqx1dsn3 https://c.godbolt.org/z/6zqx1dsn3 I've fully annotated it, so it might seem like more than it is. About half the macro code is from the original article (the chunk at the top). And I do implement both transforms for you. Each one I think is only 6 lines of code by itself, despite the rediculous amount of exposition in the comments. If you have any questions about it, let me know.