GNU bug report logs - #76535
Recommend against turn-on-<FOO>-mode functions

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Stefan Kangas <stefankangas <at> gmail.com>
To: bug-gnu-emacs <at> gnu.org
Subject: Recommend against turn-on-<FOO>-mode functions
Date: Mon, 24 Feb 2025 16:34:23 -0600

Severity: wishlist

How about adding to tips.texi a recommendation not to add any new
functions like these?

    (defun turn-on-<FOO>-mode ()
      (<FOO>-mode 1))
    (defun turn-off-<FOO>-mode ()
      (<FOO>-mode -1))

I think they are redundant in almost all cases, but it seems to me that
they are sometimes added pretty much routinely.

Message #8 received at 76535 <at> debbugs.gnu.org (full text, mbox):

From: Drew Adams <drew.adams <at> oracle.com>
To: Stefan Kangas <stefankangas <at> gmail.com>, "76535 <at> debbugs.gnu.org"
 <76535 <at> debbugs.gnu.org>
Cc: Stefan Monnier <monnier <at> iro.umontreal.ca>
Subject: RE: [External] : bug#76535: Recommend against turn-on-<FOO>-mode
 functions
Date: Tue, 25 Feb 2025 02:18:02 +0000

> Severity: wishlist
> 
> How about adding to tips.texi a recommendation not to add any new
> functions like these?
> 
>     (defun turn-on-<FOO>-mode ()
>       (<FOO>-mode 1))
>     (defun turn-off-<FOO>-mode ()
>       (<FOO>-mode -1))
> 
> I think they are redundant in almost all cases, but it seems to me that
> they are sometimes added pretty much routinely.

They aren't redundant for global minor modes created using
`define-global-minor-mode' and `define-globalized-minor-mode',
AFAIK.  Arg TURN-ON is a required argument.

  TURN-ON is a function that will be called with no args in every buffer
  and that should try to turn MODE on if applicable for that buffer.

Message #11 received at 76535 <at> debbugs.gnu.org (full text, mbox):

From: Stefan Monnier <monnier <at> iro.umontreal.ca>
To: Drew Adams <drew.adams <at> oracle.com>
Cc: Stefan Kangas <stefankangas <at> gmail.com>,
 "76535 <at> debbugs.gnu.org" <76535 <at> debbugs.gnu.org>
Subject: Re: [External] : bug#76535: Recommend against turn-on-<FOO>-mode
 functions
Date: Mon, 24 Feb 2025 23:23:02 -0500

> They aren't redundant for global minor modes created using
> `define-global-minor-mode' and `define-globalized-minor-mode',
> AFAIK.  Arg TURN-ON is a required argument.
>
>   TURN-ON is a function that will be called with no args in every buffer
>   and that should try to turn MODE on if applicable for that buffer.

Just because the arg is called "TURN-ON" doesn't mean it needs to take
an argument called `turn-on-FOO-mode` nor that it should behave the same
as `turn-on-FOO-mode`.


        Stefan

Message #14 received at 76535 <at> debbugs.gnu.org (full text, mbox):

From: Drew Adams <drew.adams <at> oracle.com>
To: Stefan Monnier <monnier <at> iro.umontreal.ca>
Cc: Stefan Kangas <stefankangas <at> gmail.com>,
 "76535 <at> debbugs.gnu.org" <76535 <at> debbugs.gnu.org>
Subject: RE: [External] : bug#76535: Recommend against turn-on-<FOO>-mode
 functions
Date: Tue, 25 Feb 2025 05:36:44 +0000

> > They aren't redundant for global minor modes created using
> > `define-global-minor-mode' and `define-globalized-minor-mode',
> > AFAIK.  Arg TURN-ON is a required argument.
> >
> >   TURN-ON is a function that will be called with no args in every
> >   buffer and that should try to turn MODE on if applicable for
> >   that buffer.
> 
> Just because the arg is called "TURN-ON" doesn't mean it needs to take
> an argument called `turn-on-FOO-mode` nor that it should behave the same
> as `turn-on-FOO-mode`.

Maybe I misunderstood the bug request; sorry, if so.

I didn't understand it to be about functions named
that way (or any particular way).

I don't think the wishlist wish was very clear, if
my understanding was indeed incorrect:

  How about adding to tips.texi a recommendation
  not to add any new functions like these?
                               ^^^^^^^^^^

    (defun turn-on-<FOO>-mode () (<FOO>-mode 1))
    (defun turn-off-<FOO>-mode () (<FOO>-mode -1))

Just what was meant by "like these"?

I understood "any new functions like these" to mean
any TURN-ON functions, with whatever name and with
whatever behavior, as long as they try to turn on
the mode whenever applicable in some buffer.  IOW,
just what the doc for arg TURN-ON says:

  a function that will be called with no args in
  every buffer and that should try to turn MODE on
  if applicable for that buffer

What else is the wish advising against, if not such
a function?

Provided you're right, and such a TURN-ON function
wasn't what was meant, and won't be what's proscribed
in the proposed "tips", great.

In that case, please at least come up with some clear
wording for the tips.  And for the wishlist proposal,
please say clearly what's being proposed - just what
do you want to advise users not to do?

But in that case, why would any such tips be needed?
Would anyone really think, reading that doc, that the
required TURN-ON arg needs to be a function named
`turn-on-...-mode'?  Has that actually been a problem
- users thinking that?

It's also not clear to me just what you mean by

  "nor that it should behave the same as
  `turn-on-FOO-mode`"

What exactly is the `turn-on-FOO-mode' behavior that
you want to tell users the function doesn't need to
provide, if by that you mean something other than
just be able to be called with no args in any buffer
and when called "try to turn MODE on if applicable
for that buffer"?

You say it doesn't need to behave "the same as
`turn-on-FOO-mode'".  What does that mean?  How does
the presumed function `turn-on-FOO-mode' behave, if
not just as described for arg TURN-ON?  What behavior
doesn't the function need to have?

Sorry I'm not getting your drift.  Can you clarify
it a bit?

Message #17 received at 76535 <at> debbugs.gnu.org (full text, mbox):

From: Sean Whitton <spwhitton <at> spwhitton.name>
To: Stefan Kangas <stefankangas <at> gmail.com>
Cc: Stefan Monnier <monnier <at> iro.umontreal.ca>, 76535 <at> debbugs.gnu.org
Subject: Re: bug#76535: Recommend against turn-on-<FOO>-mode functions
Date: Mon, 10 Mar 2025 13:16:06 +0800

Hello,

On Mon 24 Feb 2025 at 04:34pm -06, Stefan Kangas wrote:

> Severity: wishlist
>
> How about adding to tips.texi a recommendation not to add any new
> functions like these?
>
>     (defun turn-on-<FOO>-mode ()
>       (<FOO>-mode 1))
>     (defun turn-off-<FOO>-mode ()
>       (<FOO>-mode -1))
>
> I think they are redundant in almost all cases, but it seems to me that
> they are sometimes added pretty much routinely.

What about when you want to put

    (add-hook 'foo-mode 'turn-on-bar-mode)

in your init?  Without the wrapper, you need a (lambda () ...) which
isn't great.

-- 
Sean Whitton

Message #20 received at 76535 <at> debbugs.gnu.org (full text, mbox):

From: Stefan Kangas <stefankangas <at> gmail.com>
To: Sean Whitton <spwhitton <at> spwhitton.name>
Cc: Stefan Monnier <monnier <at> iro.umontreal.ca>, 76535 <at> debbugs.gnu.org
Subject: Re: bug#76535: Recommend against turn-on-<FOO>-mode functions
Date: Mon, 10 Mar 2025 05:28:27 +0000

Sean Whitton <spwhitton <at> spwhitton.name> writes:

> On Mon 24 Feb 2025 at 04:34pm -06, Stefan Kangas wrote:
>
>> Severity: wishlist
>>
>> How about adding to tips.texi a recommendation not to add any new
>> functions like these?
>>
>>     (defun turn-on-<FOO>-mode ()
>>       (<FOO>-mode 1))
>>     (defun turn-off-<FOO>-mode ()
>>       (<FOO>-mode -1))
>>
>> I think they are redundant in almost all cases, but it seems to me that
>> they are sometimes added pretty much routinely.
>
> What about when you want to put
>
>     (add-hook 'foo-mode 'turn-on-bar-mode)
>
> in your init?  Without the wrapper, you need a (lambda () ...) which
> isn't great.

I think `define-minor-mode` is supposed to generate code that makes

    (add-hook 'foo-mode 'bar-mode)

always turn the minor mode on, without the wrapper.

See (info "(elisp) Minor Mode Conventions"):

     Enabling or disabling a minor mode twice in direct succession
     should not fail and should do the same thing as enabling or
     disabling it only once.  In other words, the minor mode command
     should be idempotent.

Message #23 received at 76535 <at> debbugs.gnu.org (full text, mbox):

From: Stefan Kangas <stefankangas <at> gmail.com>
To: Sean Whitton <spwhitton <at> spwhitton.name>
Cc: Stefan Monnier <monnier <at> iro.umontreal.ca>, 76535 <at> debbugs.gnu.org
Subject: Re: bug#76535: Recommend against turn-on-<FOO>-mode functions
Date: Mon, 10 Mar 2025 05:40:23 +0000

Stefan Kangas <stefankangas <at> gmail.com> writes:

> Sean Whitton <spwhitton <at> spwhitton.name> writes:
>
>> On Mon 24 Feb 2025 at 04:34pm -06, Stefan Kangas wrote:
>>
>>> Severity: wishlist
>>>
>>> How about adding to tips.texi a recommendation not to add any new
>>> functions like these?
>>>
>>>     (defun turn-on-<FOO>-mode ()
>>>       (<FOO>-mode 1))
>>>     (defun turn-off-<FOO>-mode ()
>>>       (<FOO>-mode -1))
>>>
>>> I think they are redundant in almost all cases, but it seems to me that
>>> they are sometimes added pretty much routinely.
>>
>> What about when you want to put
>>
>>     (add-hook 'foo-mode 'turn-on-bar-mode)
>>
>> in your init?  Without the wrapper, you need a (lambda () ...) which
>> isn't great.
>
> I think `define-minor-mode` is supposed to generate code that makes
>
>     (add-hook 'foo-mode 'bar-mode)
>
> always turn the minor mode on, without the wrapper.
>
> See (info "(elisp) Minor Mode Conventions"):

I quoted the wrong part:

     If the mode command is called from Lisp (i.e., non-interactively),
     it should enable the mode if the argument is omitted or ‘nil’;

Message #26 received at 76535 <at> debbugs.gnu.org (full text, mbox):

From: Sean Whitton <spwhitton <at> spwhitton.name>
To: Stefan Kangas <stefankangas <at> gmail.com>
Cc: Stefan Monnier <monnier <at> iro.umontreal.ca>, 76535 <at> debbugs.gnu.org
Subject: Re: bug#76535: Recommend against turn-on-<FOO>-mode functions
Date: Mon, 10 Mar 2025 14:02:06 +0800

Hello,

On Mon 10 Mar 2025 at 05:28am GMT, Stefan Kangas wrote:

> I think `define-minor-mode` is supposed to generate code that makes
>
>     (add-hook 'foo-mode 'bar-mode)
>
> always turn the minor mode on, without the wrapper.

Oh, thanks, I guess that's new since I last looked into this.

-- 
Sean Whitton

Message #29 received at 76535 <at> debbugs.gnu.org (full text, mbox):

From: Stefan Monnier <monnier <at> iro.umontreal.ca>
To: Sean Whitton <spwhitton <at> spwhitton.name>
Cc: Stefan Kangas <stefankangas <at> gmail.com>, 76535 <at> debbugs.gnu.org
Subject: Re: bug#76535: Recommend against turn-on-<FOO>-mode functions
Date: Mon, 10 Mar 2025 11:29:04 -0400

> Oh, thanks, I guess that's new since I last looked into this.

etc/NEWS.24:

    * Incompatible Lisp Changes in Emacs 24.1
    
    ** Passing a nil argument to a minor mode function call now ENABLES
    the minor mode unconditionally.  This is so that you can write e.g.
    
        (add-hook 'text-mode-hook #'foo-mode)
    
    to enable foo-mode in Text mode buffers, removing the need for
    'turn-on-foo-mode' style functions.  This affects all mode commands
    defined by 'define-minor-mode'.  If called interactively, the mode
    command still toggles the minor mode.


- Stefan

Message #32 received at 76535 <at> debbugs.gnu.org (full text, mbox):

From: Sean Whitton <spwhitton <at> spwhitton.name>
To: Stefan Monnier <monnier <at> iro.umontreal.ca>
Cc: Stefan Kangas <stefankangas <at> gmail.com>, 76535 <at> debbugs.gnu.org
Subject: Re: bug#76535: Recommend against turn-on-<FOO>-mode functions
Date: Tue, 11 Mar 2025 09:57:38 +0800

Hello,

Sometimes you just miss things for years, huh?

Thanks for the reference.

-- 
Sean Whitton

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