C++

OK, I can see why the designers of C# did not implement the preprocessor of C++ and C. It creates obfuscated code, and its functionality, as I learned several years ago from Number One Son, its functionality is largely replaced by objects.

For me, furthermore, it doesn't go far enough. This is because the preprocessor of PL/I was Turing complete in that you could create loops in the preprocessor and, from a logical standpoint, the preprocessor was a full "computer", allowing you to ship seriously customizable (and, seriously obfuscated) solutions.

But I find the string model of C# supports the concept of "scan for any one of a SET of characters" that is found in C strspn, but FAILS to support (as far as I can determine) the concept of "scan for any one of the COMPLEMENT of a SET of characters" as seen in strcspn.