Standard extensions (logical exclusive or)

[Brandon Allbery]

> Article <3081 at alice.UUCP>, from ark at alice.UUCP (Andrew Koenig)
+----------------
| Joseph Orost suggests a new operator ^^ such that
| 	a^^b
| would be equivalent to
| 	a? (b?0:1): (b?1:0)
| 
| What is wrong with writing
| 	a!=b
| for this purpose?

C programmers like to cut corners; witness all those on1 messages that
depend on && evaluating as little as possible.  It may be in K&R, but
I've seen too many harebrained implementations of too manu programs...

The problem with a!=b is that some of us use other corner-cutters:  one
of mine is

	if (index("AIJKLRaijklr", cmdchr)) dothis();

where index (strchr for USGers) returns either NULL or a pointer.  This
will NOT work if you use != for an xor:

	if (iscmd!=index("AIJKLRaijklr", cmdchr)) dothis();

is only true if !iscmd and !index(...), since index will usually NOT
return a 1...

--bsa
-- 
  Brandon Allbery @ North Coast Xenix  |   the.world!ucbvax!decvax!cwruecmp!
6504 Chestnut Road, Independence, Ohio |       {atvax!}ncoast!{tdi1!}bsa
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			`Confusion is my natural state.'