Re: Minor mode hook run when mode is deactivated?

[Joost Kremers <joostkremers@fastmail.fm>]

On Thu, Oct 08 2020, Stefan Monnier wrote:
>> That makes sense, but it does mean that you cannot put a minor 
>> mode onto
>> another minor mode hook.[1]
>
> And expect this minor mode to be enabled/disabled along with the
> "parent" minor mode?  no, indeed!

No, not at all. :-) I added an extra hook variable that got run in 
the body of `define-minor-mode` when deactivating the "parent" 
mode, which I used to turn off the "child" minor mode. I was just 
surprised that the "child" mode was then immediately reactivated 
again.

>> 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?
>
> `C-h o <foo>-mode-hook RET` should say that it is run both when 
> leaving
> and entering.  So either your specific hook failed to mention 
> it, 

No, it's there. I just never bothered to look, because I it's a 
mode that I wrote myself. :-) I didn't realize that the mode hook 
gets a default doc string.

> or you
> looked in some other part of the doc.  In either case it sounds 
> like you
> found a documentation bug, so please report it (it's important 
> then to
> say exactly where you looked for that info).

I'll report it as a documentation bug, then. Thanks for your 
reply.


-- 
Joost Kremers
Life has its moments