About 4., there is already a preprocessor loop proposal for clang[0] and I think I have also seen it some obscure Qualcomm bluetooth chip compiler. [0]: https:

About 4., there is already a preprocessor loop proposal for clang[0] and I think I have also seen it some obscure Qualcomm bluetooth chip compiler. [0]: https://discourse.llvm.org/t/rfc-new-preprocessor-macro-directive-repeat/69253 https://discourse.llvm.org/t/rfc-new-preprocessor-macro-dire...