all messages for Emacs-related lists mirrored at yhetil.org
 help / color / mirror / code / Atom feed
From: Navy Cheng <navych@126.com>
To: help-gnu-emacs@gnu.org
Subject: Re: How to use a symbol and its value to create alist?
Date: Wed, 12 Aug 2015 09:57:13 +0800	[thread overview]
Message-ID: <20150812015712.GC22098@debian> (raw)
In-Reply-To: <87pp2tga8e.fsf@kuiper.lan.informatimago.com>

On Tue, Aug 11, 2015 at 04:39:45PM +0200, Pascal J. Bourguignon wrote:
> Navy Cheng <navych@126.com> writes:
> 
> > For example:
> >
> > (setq a 1)
> > (setq b 2)
> > (setq c 3)
> >
> > How can I a alist, like:
> 
> How can you WHAT a alist?

Sorry for that, (setq WHAT "create")

> 
> > ((a . 1) (b . 2) (c .3))
> >
> > The value of a, b and c may change, so don't do this like
> > (setq tree ((a . 1) (b . 2) (c .3)))
> 
> This is not a valid form, because (a . 1) is not a function name,
> therefore it's not possible to apply it.
> 

Sorry again, (setq tree '((a . 1) (b . 2) (c .3)))

> 
> If you want to BUILD an a-list, you can use acons:
> 
> (let ((a 1)
>       (b 2)
>       (c 3))
>   (let ((tree (acons 'a a (acons 'b b (acons 'c c '())))))
>      tree))
> --> ((a . 1) (b . 2) (c . 3))
> 
Thanks for your patient and help. Your answer is OK. I have learned
another way to do this.

(setq tree `((a . ,a) (b . ,b) (c . ,c)))




  reply	other threads:[~2015-08-12  1:57 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <mailman.8135.1439301205.904.help-gnu-emacs@gnu.org>
2015-08-11 14:39 ` How to use a symbol and its value to create alist? Pascal J. Bourguignon
2015-08-12  1:57   ` Navy Cheng [this message]
2015-08-12  0:21 ` Barry Margolin
2015-08-12  1:35   ` Navy Cheng
2015-08-11 13:52 Navy Cheng
2015-08-11 15:21 ` Ian Zimmerman
2015-08-12  1:46   ` Navy Cheng
     [not found]   ` <mailman.8160.1439343998.904.help-gnu-emacs@gnu.org>
2015-08-12  2:12     ` Pascal J. Bourguignon
2015-08-12  2:18       ` Pascal J. Bourguignon
2015-08-12  5:06         ` Navy Cheng
     [not found]         ` <mailman.8170.1439355992.904.help-gnu-emacs@gnu.org>
2015-08-12  7:03           ` Pascal J. Bourguignon

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=20150812015712.GC22098@debian \
    --to=navych@126.com \
    --cc=help-gnu-emacs@gnu.org \
    /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.