I agree with some other's in this thread: this is example is not great, but I get why it was used: to compare with X-macros. How about something that would require code-generation e.g. via libclang?

For example, what does https://miguelmartin.com/blog/nim2-review#implementing-a-sim... look like with C++26's std::meta::info?

My guess is: libclang is more suited for this situation if you care about compile times, even if Python is used.