xor

["Glenn S. Burke" <GSB@MC.LCS.MIT.EDU>]

What i don't like about XOR is that it sounds like it is in the same
class as AND and OR, and it is not all that like them.  Like it or
not, AND and OR are control constructs.  (I have never had any problem
with this, but Lisp is my first programming language.  I am somewhat
disturbed by attempts to mask this nature of them -- they may lead to
even more confusion by this deemphasis.)

I wouldn't mind the functionality, but it's not clear to me that it is
worth too much confusion.  As far as implementation is concerned, i
can see being able to implement this much better as a special operator
than as a macro.