[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Is there a way of setting a variable only when it exists?
From: |
Jean Louis |
Subject: |
Re: Is there a way of setting a variable only when it exists? |
Date: |
Tue, 15 Mar 2022 09:48:48 +0300 |
User-agent: |
Mutt/2.2.0 (2022-02-12) |
* Emanuel Berg via Users list for the GNU Emacs text editor
<help-gnu-emacs@gnu.org> [2022-03-15 06:16]:
> Stefan Monnier via Users list for the GNU Emacs text editor wrote:
>
> >> I assume it would be fairly easy to code such a macro
> >> (using `boundp'), but maybe it exists already?
> >
> > AFAIK it doesn't exist yet. The reason for it is that it is
> > not often useful. Typically there are two cases:
> >
> > - If the var exist, you want to set it and if not you have
> > no fallback. In that case, it is typically harmless to set
> > the var even when it doesn't exist, so the code just uses
> > `setq` without bothering to test `boundp`.
> >
> > - If the var exist you want to set it, and if it doesn't you
> > want to do something else. In that case, the something
> > else tends to depend on the specifics so (if (boundp 'foo)
> > (setq foo ..) ...) is about s good as it gets.
>
> If it exists set it with `setq'. If it doesn't exist, create
> and set it ... with `setq'?
Hahahahha -- exactly.
--
Jean
Take action in Free Software Foundation campaigns:
https://www.fsf.org/campaigns
In support of Richard M. Stallman
https://stallmansupport.org/
- Re: Is there a way of setting a variable only when it exists?, (continued)
- Re: Is there a way of setting a variable only when it exists?, Emanuel Berg, 2022/03/15
- RE: [External] : Re: Is there a way of setting a variable only when it exists?, Drew Adams, 2022/03/15
- Re: Is there a way of setting a variable only when it exists?, Emanuel Berg, 2022/03/15
- RE: [External] : Re: Is there a way of setting a variable only when it exists?, Drew Adams, 2022/03/15
- Re: [External] : Re: Is there a way of setting a variable only when it exists?, Marcin Borkowski, 2022/03/16
- Re: Is there a way of setting a variable only when it exists?, Michael Heerdegen, 2022/03/15
- Re: Is there a way of setting a variable only when it exists?, Marcin Borkowski, 2022/03/16
- Re: Is there a way of setting a variable only when it exists?, Tomas Nordin, 2022/03/16
- Re: Is there a way of setting a variable only when it exists?, Marcin Borkowski, 2022/03/16
- Re: Is there a way of setting a variable only when it exists?, Emanuel Berg, 2022/03/17
- Re: Is there a way of setting a variable only when it exists?,
Jean Louis <=
Re: Is there a way of setting a variable only when it exists?, Michael Heerdegen, 2022/03/14
- Re: Is there a way of setting a variable only when it exists?, Marcin Borkowski, 2022/03/15
- Re: Is there a way of setting a variable only when it exists?, Emanuel Berg, 2022/03/15
- Re: Is there a way of setting a variable only when it exists?, Michael Heerdegen, 2022/03/15
- Re: Is there a way of setting a variable only when it exists?, Marcin Borkowski, 2022/03/16
- Re: Is there a way of setting a variable only when it exists?, Michael Heerdegen, 2022/03/16
- Re: Is there a way of setting a variable only when it exists?, Marcin Borkowski, 2022/03/18
- Re: Is there a way of setting a variable only when it exists?, Emanuel Berg, 2022/03/17
- Re: Is there a way of setting a variable only when it exists?, Stefan Monnier, 2022/03/17
- Re: Is there a way of setting a variable only when it exists?, Marcin Borkowski, 2022/03/18