TITLE: Incrementing enumerations

PROBLEM: 

[ This picks up on a discussion concerning operators involving enums,
  specifically, the increment operator. IMHO, it would be better and
  safer to create a class for this. -adc ]


RESPONSE: grumpy@cbnewse.cb.att.com (Paul J Lucas)

The correct thing to do is to overload operator++ for the enum;
however, this is a very recet ANSI adoption, so your compiler
won't allow it.


RESPONSE: damian@cs.monash.edu.au (Damian Conway)

Out of interest:
      1. What was the syntax that was adopted for this?
      2. What other operators can be overloaded for enums?


RESPONSE: dag@control.lth.se (Dag Bruck)

The same syntax as for overloading on class types; we lifted a
semantic restriction because other changes to C++ (a couple of years
back) solved a potential problem.

Here is an example:

	enum Season {Winter, Spring, Summer, Fall};

	Season operator ++ (Season s) {
		switch (s) {
		case Winter: return Spring;
		case Spring: return Summer;
		case Summer: return Fall;
		case Fall:   return Winter:
		default:
			assert(0);	// some garbage bits
		}
	}

There are of course many other ways to implement this function.  Note
however that there was no need to do type casting.

If you're willing to implement a large number of functions (perhaps
with some automated tool), you will be able to implement bounded-range
integers with enums.

All operators that can be overloaded for class types [are available
as enum operators].