GNU bug report logs - #22299
Obsolete selective-display

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Message #1 received at quiet <at> debbugs.gnu.org (full text, mbox):

From: Glenn Morris <rgm <at> gnu.org>
To: quiet <at> debbugs.gnu.org
Subject: Obsolete selective-display
Date: Sun, 03 Jan 2016 14:11:54 -0500

Package: emacs
Version: 25.1
Severity: wishlist

Make selective-display obsolete. See eg http://debbugs.gnu.org/1092#34 .

Message #4 received at 22299 <at> debbugs.gnu.org (full text, mbox):

From: Glenn Morris <rgm <at> gnu.org>
To: 22299 <at> debbugs.gnu.org
Subject: Re: Obsolete selective-display
Date: Mon, 18 Mar 2019 12:09:59 -0400

Perhaps this is done as of 2f50a99 and similar.

Message #7 received at 22299 <at> debbugs.gnu.org (full text, mbox):

From: Lars Ingebrigtsen <larsi <at> gnus.org>
To: Glenn Morris <rgm <at> gnu.org>
Cc: Stefan Monnier <monnier <at> iro.umontreal.ca>, 22299 <at> debbugs.gnu.org
Subject: Re: bug#22299: Obsolete selective-display
Date: Thu, 21 Jan 2021 17:56:22 +0100

Glenn Morris <rgm <at> gnu.org> writes:

> Perhaps this is done as of 2f50a99 and similar.

The `selective-display' variable isn't marked as deprecated, though, and
is used throughout Emacs...  should is be marked as such?  And the
usages either removed (from the callers) or warnings suppressed (in
simple.el etc).

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

Message #10 received at 22299 <at> debbugs.gnu.org (full text, mbox):

From: Stefan Monnier <monnier <at> iro.umontreal.ca>
To: Lars Ingebrigtsen <larsi <at> gnus.org>
Cc: Glenn Morris <rgm <at> gnu.org>, 22299 <at> debbugs.gnu.org
Subject: Re: bug#22299: Obsolete selective-display
Date: Thu, 21 Jan 2021 12:14:46 -0500

>> Perhaps this is done as of 2f50a99 and similar.
> The `selective-display' variable isn't marked as deprecated, though, and
> is used throughout Emacs...

I don't think it's *used* throughout.  AFAIK it's *obeyed* at many
places, in case someone still uses it (it's obsolete, not removed).
If you spot an actual use, please report it as a bug.

> should it be marked as such?  And the usages either removed (from the
> callers) or warnings suppressed (in simple.el etc).

The problem is that the var has 2 uses:
- one is the obsolete value `t` whereby \r.* is hidden
- the other is when it's set to an integer N whereby it hides lines with
  a deeper indentation than N.

The second one is a UI functionality and it's sufficiently "not terribly
useful" that nobody bothered to write a replacement for it using
overlays (instead, all the possible replacements provide a more tailored
functionality).


        Stefan

Message #13 received at 22299 <at> debbugs.gnu.org (full text, mbox):

From: Eli Zaretskii <eliz <at> gnu.org>
To: Lars Ingebrigtsen <larsi <at> gnus.org>
Cc: rgm <at> gnu.org, monnier <at> iro.umontreal.ca, 22299 <at> debbugs.gnu.org
Subject: Re: bug#22299: Obsolete selective-display
Date: Thu, 21 Jan 2021 21:42:03 +0200

> From: Lars Ingebrigtsen <larsi <at> gnus.org>
> Date: Thu, 21 Jan 2021 17:56:22 +0100
> Cc: Stefan Monnier <monnier <at> iro.umontreal.ca>, 22299 <at> debbugs.gnu.org
> 
> Glenn Morris <rgm <at> gnu.org> writes:
> 
> > Perhaps this is done as of 2f50a99 and similar.
> 
> The `selective-display' variable isn't marked as deprecated, though, and
> is used throughout Emacs...  should is be marked as such?

I use set-selective-display all the time, so I'd be unhappy if it were
obsoleted, FWIW.

Message #16 received at 22299 <at> debbugs.gnu.org (full text, mbox):

From: Lars Ingebrigtsen <larsi <at> gnus.org>
To: Stefan Monnier <monnier <at> iro.umontreal.ca>
Cc: Glenn Morris <rgm <at> gnu.org>, 22299 <at> debbugs.gnu.org
Subject: Re: bug#22299: Obsolete selective-display
Date: Fri, 22 Jan 2021 18:22:50 +0100

Stefan Monnier <monnier <at> iro.umontreal.ca> writes:

>> should it be marked as such?  And the usages either removed (from the
>> callers) or warnings suppressed (in simple.el etc).
>
> The problem is that the var has 2 uses:
> - one is the obsolete value `t` whereby \r.* is hidden
> - the other is when it's set to an integer N whereby it hides lines with
>   a deeper indentation than N.

Oh, I see.  I should have read that node in the manual.  :-)

Anyway, I've grepped through the Emacs tree, and I can't find any places
where we're binding/setting `selective-display' to t, so there indeed
doesn't seem to be any usages of the obsolete form.

> The second one is a UI functionality and it's sufficiently "not terribly
> useful" that nobody bothered to write a replacement for it using
> overlays (instead, all the possible replacements provide a more tailored
> functionality).

Right.  So if we don't want to obsolete the other form (and Eli says he
uses it all the time, so it doesn't sound like we want to), then I guess
there's nothing more to be done here?  So I'm closing this bug report.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

Message #21 received at 22299 <at> debbugs.gnu.org (full text, mbox):

From: Stefan Monnier <monnier <at> iro.umontreal.ca>
To: Lars Ingebrigtsen <larsi <at> gnus.org>
Cc: Glenn Morris <rgm <at> gnu.org>, 22299 <at> debbugs.gnu.org
Subject: Re: bug#22299: Obsolete selective-display
Date: Fri, 22 Jan 2021 12:55:16 -0500

>> The second one is a UI functionality and it's sufficiently "not terribly
>> useful" that nobody bothered to write a replacement for it using
>> overlays (instead, all the possible replacements provide a more tailored
>> functionality).
> Right.  So if we don't want to obsolete the other form (and Eli says he
> uses it all the time, so it doesn't sound like we want to), then I guess
> there's nothing more to be done here?  So I'm closing this bug report.

We could try and re-implement `set-selective-display` using overlays,
of course.

And we could try and provide some other "text hiding" package more
specifically tailored to Eli's uses.

But really, I don't mind the `set-selective-display` feature now how
it's currently implemented, so I don't see a strong need to
replace/obsolete it.

The "selective-display == t" case is the one I care about because it
causes (well, "caused" since we started to drop that kind of
compatibility code) complexity in packages which had to deal with "end
of line can also be \r".


        Stefan

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