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- To: common-lisp@SU-AI.ARPA
- Subject: XOR
- From: David A. Moon <Moon@SCRC-STONY-BROOK.ARPA>
- Date: Thu, 26 Dec 85 14:30 EST
- In-reply-to: The message of 22 Dec 85 17:15-EST from MURRAY%umass-cs.csnet@CSNET-RELAY.ARPA
- Supersedes: <851226130548.6.MOON@EUPHRATES.SCRC.Symbolics.COM>
Date: Sun, 22 Dec 85 17:15 EST
I think the discussion about whether there should be an XOR
function is very much off the mark. I think the criterion for
including any new operator in the language should be one of
1) It is not possible to write it in Common Lisp.
2) It can be implemented MUCH more
efficiently in an implemention dependant way.
3) It requires a lot of programming effort (and is generally useful).
As long as an operator is implementable in Common Lisp, your program
would still be portable.
The only problem that could arise is that your function/macro
is called something that later on becomes defined in Common Lisp, with
different syntax/semantics. But that problem exists with ANY operator
that you define, and packages can deal with it. Thus I see no reason
to include something like XOR. The language is certainly big enough
I agree completely. I could not have stated my position as clearly and
completely as you have.
LATER: I also agree with the other people who said that a 4th criterion
should be added, that enough people will use it that it's important to
standardize the name, even though everyone could implement it for themselves.
They seemed to think that by saying this they were disagreeing with you,
but I didn't read what you said as disagreeing with that sentiment.
[Rest of message, about other issues, not included in this particular reply]