From: Pascal Bourguignon <spam@thalassa.informatimago.com>
Subject: Re: Elisp: What does ''nil mean?
Date: 16 May 2003 18:34:25 +0200 [thread overview]
Message-ID: <87wugqzw8e.fsf@thalassa.informatimago.com> (raw)
In-Reply-To: wk7k8r9la0.fsf@t-online.de
Thomas Gehrlein <thomas.gehrlein@t-online.de> writes:
> David Kastrup <dak@gnu.org> writes:
>
> > Thomas Gehrlein <thomas.gehrlein@t-online.de> writes:
> >
> > > The following line is from easy-menu-create-menu:
> > >
> > > ((eq keyword :active) (setq enable (or arg ''nil)))
> > >
> > > It is part of a (cond ...).
> > >
> > > What does "''nil" mean?
> >
> > The same as '(quote nil), an unevaluated list with the two members
> > quote and nil.
>
> Is this the same as (quote (quote nil))?
Yes.
> Why would you quote nil and not evaluate it? And if you evaluate
> it: Isn't nil the same as (quote nil)?
Just try it!
(show (car ''nil)) | (show (car 'nil)) | (show (car nil))
==> quote | ==> nil | ==> nil
(show (cdr ''nil)) | (show (cdr 'nil)) | (show (cdr nil))
==> (nil) | ==> nil | ==> nil
--
__Pascal_Bourguignon__ http://www.informatimago.com/
----------------------------------------------------------------------
Do not adjust your mind, there is a fault in reality.
prev parent reply other threads:[~2003-05-16 16:34 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-05-16 9:00 Elisp: What does ''nil mean? Thomas Gehrlein
2003-05-16 10:45 ` David Kastrup
2003-05-16 11:35 ` Thomas Gehrlein
2003-05-16 11:57 ` David Kastrup
2003-05-16 16:16 ` Thomas Gehrlein
2003-05-16 16:34 ` Pascal Bourguignon [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87wugqzw8e.fsf@thalassa.informatimago.com \
--to=spam@thalassa.informatimago.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this external index
https://git.savannah.gnu.org/cgit/emacs.git
https://git.savannah.gnu.org/cgit/emacs/org-mode.git
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.