This was back in 80s when you were working on c compilers? That’s an interesting story (80s compiler scene and what you worked on) I’ve picked up bits and pieces over the years, have you written it up anywhere? Would be benefit for many I think.
No need for anyone else to struggle to implement a preprocessor.
microsoft fixed their broken c preprocessor implementation just a few years ago
They could have just asked me :-)
They were deliberately leaving their C compiler broken because they considered C++ to be the replacement for C.
C++ uses an identical preprocessor.
That has sometimes been true, but for example C++ didn't have variadic macros, maybe still doesn't, because they were added to C after Microsoft decided to stop following C development. https://stackoverflow.com/a/21515839 goes into details of other differences.