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From: Joost Kremers <joostkremers@fastmail.fm>
To: Stefan Monnier <monnier@iro.umontreal.ca>
Cc: help-gnu-emacs@gnu.org
Subject: Re: Minor mode hook run when mode is deactivated?
Date: Thu, 08 Oct 2020 08:44:30 +0200	[thread overview]
Message-ID: <87h7r5b4j5.fsf@fastmail.fm> (raw)
In-Reply-To: <jwvtuv5pprc.fsf-monnier+emacs@gnu.org>


On Thu, Oct 08 2020, Stefan Monnier wrote:
> If you need to do something when a minor mode is activated, you 
> most
> likely also need to do something to "undo" it when the mode
> is deactivated.  So, yes, the minor mode hooks are run both when
> activating and when deactivating, and they should check the 
> value of the
> minor mode variable to know which it is.

That makes sense, but it does mean that you cannot put a minor 
mode onto another minor mode hook.[1]

Which is OK, I was just surprised that I wasn't able to find 
anything about this in the documentation. Is in there and I just 
didn't search well enough, or should it perhaps be added?

Joost


Footnotes:
[1]  That was my scenario. I have a minor mode that I wrote and to 
which I added an extra hook that's run when the mode is 
deactivated. I thought this would allow me to turn off other minor 
modes that I had activated in my minor mode's hook, but it wasn't 
working. Turns out the minor mode hook is also run when the mode 
is deactivated, after my additional deactivate-hook was run... 
Details here 
<https://github.com/joostkremers/writeroom-mode/issues/63> if 
anyone's interested.



-- 
Joost Kremers
Life has its moments



  reply	other threads:[~2020-10-08  6:44 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-07 23:15 Minor mode hook run when mode is deactivated? Joost Kremers
2020-10-07 23:45 ` Stefan Monnier
2020-10-08  6:44   ` Joost Kremers [this message]
2020-10-08 13:53     ` Stefan Monnier
2020-10-08 14:33       ` Joost Kremers

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