Unicode operators for C

C11 has added a certain level of Unicode support to C, but I think for C2x it will be time to go a step further and put C in line with general usage of special characters as they are normalized by Unicode. In particular, it is time to get rid of restrictions in operator naming that stem from the limited availability of special characters 30 years ago, when all of this was invented.

named constants

[Note: This post is now largely obsolete, I only keep it up for reference. Named constants are new features in C23 (latest public draft) by means of the constexpr construct, and also the underlying type of an enumeration can now be prescribed.]

It is now exactly two years that I wrote about the underestimated register keyword in C. Today I’d like to tell about an idea that is spinning in my head ever since, that register variables in file scope would be a perfect tool to offer a feature that is much missed in C: named constants of arbitrary data types.

The whole of it is a bit technical, be warned, but the essence of it will be to declare something like the following in a header file, without creating linkage or “instantiation” problems, and helping us to write readable and debuggable code:

register const double PI = 3.14159265358979323846;

typedef struct listElem listElem;
struct listElem { unsigned val; listElem* next; };

register const listElem singleton = { 0 };