I'm on my phone, but if you start with the top 8 lines in the code box under the ascii art, you'll get an implementation of `H4X0R_MAP()`; the bottom two lines are an example, and you can just write yourself a body that produces one term. Only thing you need to know beyond that is the stringify operator.

And I should say, if you want to apply the same transformation to arguments twice, but call F() separately from G() per your starting example, you'd just apply your map twice in your top-level macro.