[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: |
Emanuel Berg |
Subject: |
Re: Is there a way of setting a variable only when it exists? |
Date: |
Mon, 14 Mar 2022 14:48:10 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/29.0.50 (gnu/linux) |
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'?
--
underground experts united
https://dataswamp.org/~incal
- Is there a way of setting a variable only when it exists?, Marcin Borkowski, 2022/03/14
- Re: Is there a way of setting a variable only when it exists?, Eli Zaretskii, 2022/03/14
- Re: Is there a way of setting a variable only when it exists?, Stefan Monnier, 2022/03/14
- Re: Is there a way of setting a variable only when it exists?,
Emanuel Berg <=
- Re: Is there a way of setting a variable only when it exists?, tomas, 2022/03/15
- Re: Is there a way of setting a variable only when it exists?, Jean Louis, 2022/03/15
- Re: Is there a way of setting a variable only when it exists?, tomas, 2022/03/15
- Re: Is there a way of setting a variable only when it exists?, Jean Louis, 2022/03/15
- Re: Is there a way of setting a variable only when it exists?, tomas, 2022/03/15
- Re: Is there a way of setting a variable only when it exists?, Emanuel Berg, 2022/03/15