Re: Minor mode hook run when mode is deactivated?

[Joost Kremers <joostkremers@fastmail.fm>]

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