From: Drew Adams <drew.adams@oracle.com>
To: Michael Heerdegen <michael_heerdegen@web.de>,
Barry Fishman <barry@ecubist.org>
Cc: emacs-devel@gnu.org
Subject: RE: 7 logical-xor implementations in source tree
Date: Wed, 31 Jul 2019 15:03:02 -0700 (PDT) [thread overview]
Message-ID: <f6b19ed9-464b-41e1-877a-4317a75d8da0@default> (raw)
In-Reply-To: <4de86e2c-18ab-4cf1-9a70-e43310234ad0@default>
> Is it hard to understand (eq (not a) (not b))?
Well, someone off list pointed out that that is
(not (xor a b)); it is not (xor a b). Yes, of
course.
I thought it'd be enough to speak to the general
thing under discussion, for which opposite-value
names such as "equiv", "iff", and `<=>' were
proposed.
But to be more pedantic/correct, is it hard to
understand (not (eq (not a) (not b)))?
Or if you prefer, (eq (not a) (not (not b)))?
Is lack of an `xor' (or an `equiv') operator
a problem in practice? How often have you felt
the need for it, really?
Why do you think Emacs Lisp, which was by design
smaller than Common Lisp, needs such a function,
but Common Lisp does not? What's the special
need we have for this?
next prev parent reply other threads:[~2019-07-31 22:03 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-22 18:48 7 logical-xor implementations in source tree Oleh Krehel
2019-07-22 21:47 ` Basil L. Contovounesios
2019-07-24 22:17 ` Basil L. Contovounesios
2019-07-24 23:15 ` Stefan Monnier
2019-07-24 23:44 ` Basil L. Contovounesios
2019-07-25 12:07 ` Mattias Engdegård
2019-07-25 17:28 ` Paul Eggert
2019-07-25 17:46 ` Mattias Engdegård
2019-07-28 7:09 ` Philippe Schnoebelen
2019-07-28 8:04 ` Alan Mackenzie
2019-07-28 19:43 ` Marcin Borkowski
2019-07-30 9:36 ` Alan Mackenzie
2019-07-30 10:57 ` Philippe Schnoebelen
2019-07-30 11:28 ` Andy Moreton
2019-07-30 12:34 ` Stefan Monnier
2019-07-30 14:25 ` Barry Fishman
2019-07-31 3:16 ` Richard Stallman
2019-07-31 15:20 ` Barry Fishman
2019-07-31 15:42 ` Stefan Monnier
2019-07-31 20:22 ` Basil L. Contovounesios
2019-07-31 21:15 ` Michael Heerdegen
2019-07-31 22:28 ` Mattias Engdegård
2019-07-31 23:39 ` Basil L. Contovounesios
2019-08-02 10:29 ` Mattias Engdegård
2019-08-02 10:59 ` Basil L. Contovounesios
2019-08-06 11:58 ` Mattias Engdegård
2019-07-31 20:31 ` Michael Heerdegen
2019-07-31 21:38 ` Drew Adams
2019-07-31 22:03 ` Drew Adams [this message]
2019-07-31 22:05 ` Basil L. Contovounesios
2019-07-31 23:20 ` Drew Adams
2019-08-01 0:09 ` Basil L. Contovounesios
2019-07-31 17:12 ` Marcin Borkowski
2019-07-23 8:39 ` Andy Moreton
2019-07-23 9:08 ` Basil L. Contovounesios
2019-07-23 9:14 ` Mattias Engdegård
2019-07-23 10:26 ` Andy Moreton
2019-07-23 10:40 ` Andreas Schwab
2019-07-23 12:11 ` Andy Moreton
2019-07-23 13:20 ` Basil L. Contovounesios
2019-07-23 13:54 ` Andy Moreton
2019-07-24 22:21 ` Basil L. Contovounesios
2019-07-23 10:44 ` Basil L. Contovounesios
2019-07-23 11:01 ` Yuri Khan
2019-07-25 21:46 ` Juri Linkov
2019-07-23 11:24 ` Noam Postavsky
2019-07-23 12:38 ` Stefan Monnier
2019-07-23 16:41 ` Mattias Engdegård
2019-07-23 17:12 ` Eli Zaretskii
2019-07-23 17:48 ` Paul Eggert
2019-07-23 19:45 ` Stefan Monnier
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