bug#66716: Reconcile display-fill-column-indicator-character behavior and customization description

bug#66716: Reconcile display-fill-column-indicator-character behavior and customization description

[Joseph Turner via Bug reports for GNU Emacs, the Swiss army knife of text editors]

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Tags: patch

Tags: patch

Tags: patch

AFAICT, setting display-fill-column-indicator-character to nil means
that no fill indicator is displayed. This patch changes the
customization description to match the current behavior.

However, I like the behavior that's currently described in the
customization option:

"If possible, use U+2502 to indicate fill column, otherwise use |"

What do folks think about changing the behavior of
display-fill-column-indicator-character to match this description?

Thank you!!

Joseph


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From 846252d0c3912623ba2d8ff9832e00dfa00fc091 Mon Sep 17 00:00:00 2001
From: Joseph Turner <joseph@breatheoutbreathe.in>
Date: Mon, 23 Oct 2023 14:20:09 -0700
Subject: [PATCH] Fix customization description:
 display-fill-column-indicator-character

* lisp/cus-start.el (standard): Change the description of the nil
value to its current behavior: to not display a fill indicator.
---
 lisp/cus-start.el | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lisp/cus-start.el b/lisp/cus-start.el
index 054683d7cf6..2fc5d3d727c 100644
--- a/lisp/cus-start.el
+++ b/lisp/cus-start.el
@@ -806,7 +806,7 @@ since it could result in memory overflow and make Emacs crash."
                       :value ?│)
                (character :tag "Use | to indicate fill column"
                       :value ?|)
-               (const :tag "If possible, use U+2502 to indicate fill column, otherwise use |"
+               (const :tag "Do not indicate fill column"
                       :value nil)
                character)
               "27.1"
-- 
2.41.0

bug#66716: Reconcile display-fill-column-indicator-character behavior and customization description

[Eli Zaretskii]

> Date: Mon, 23 Oct 2023 14:23:06 -0700
> From:  Joseph Turner via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> 
> AFAICT, setting display-fill-column-indicator-character to nil means
> that no fill indicator is displayed.

That's not true, AFAICT.  The default value is nil, but when you turn
on the mode, it modifies the value of the character to be either
U+2502 or '|'.

> This patch changes the customization description to match the
> current behavior.

I don't think the patch is correct.

> However, I like the behavior that's currently described in the
> customization option:
> 
> "If possible, use U+2502 to indicate fill column, otherwise use |"
> 
> What do folks think about changing the behavior of
> display-fill-column-indicator-character to match this description?

I don't understand the proposal.  We don't use U+2502 by default
because not all terminals support it.

bug#66716: Reconcile display-fill-column-indicator-character behavior and customization description

[Joseph Turner via Bug reports for GNU Emacs, the Swiss army knife of text editors]

Eli Zaretskii <eliz@gnu.org> writes:

>> Date: Mon, 23 Oct 2023 14:23:06 -0700
>> From:  Joseph Turner via "Bug reports for GNU Emacs,
>>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
>>
>> AFAICT, setting display-fill-column-indicator-character to nil means
>> that no fill indicator is displayed.
>
> That's not true, AFAICT.  The default value is nil, but when you turn
> on the mode, it modifies the value of the character to be either
> U+2502 or '|'.
>
>> This patch changes the customization description to match the
>> current behavior.
>
> I don't think the patch is correct.

Indeed, the patch is incorrect.  I misunderstood the behavior of
display-fill-column-indicator-mode when
display-fill-column-indicator-character is nil.

>> However, I like the behavior that's currently described in the
>> customization option:
>>
>> "If possible, use U+2502 to indicate fill column, otherwise use |"
>>
>> What do folks think about changing the behavior of
>> display-fill-column-indicator-character to match this description?
>
> I don't understand the proposal.  We don't use U+2502 by default
> because not all terminals support it.

When enabling display-fill-column-indicator in .dir-locals.el, is it
possible to dynamically set display-fill-column-indicator-character
according to what characters are displayable without using eval?

Currently in my project, I have:

((emacs-lisp-mode . ((display-fill-column-indicator . t)
                     ;; This won't work on some terminals
                     (display-fill-column-indicator-character . ?\u2502)
                     (fill-column . 80))))

Please let me know if you have suggestions for improvement!

Thank you!!!

Joseph

bug#66716: Reconcile display-fill-column-indicator-character behavior and customization description

[Eli Zaretskii]

> From: Joseph Turner <joseph@breatheoutbreathe.in>
> Cc: 66716@debbugs.gnu.org
> Date: Tue, 24 Oct 2023 12:46:11 -0700
> 
> >> What do folks think about changing the behavior of
> >> display-fill-column-indicator-character to match this description?
> >
> > I don't understand the proposal.  We don't use U+2502 by default
> > because not all terminals support it.
> 
> When enabling display-fill-column-indicator in .dir-locals.el, is it
> possible to dynamically set display-fill-column-indicator-character
> according to what characters are displayable without using eval?

I don't think so.

bug#66716: Reconcile display-fill-column-indicator-character behavior and customization description

[Joseph Turner via Bug reports for GNU Emacs, the Swiss army knife of text editors]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Joseph Turner <joseph@breatheoutbreathe.in>
>> Cc: 66716@debbugs.gnu.org
>> Date: Tue, 24 Oct 2023 12:46:11 -0700
>>
>> >> What do folks think about changing the behavior of
>> >> display-fill-column-indicator-character to match this description?
>> >
>> > I don't understand the proposal.  We don't use U+2502 by default
>> > because not all terminals support it.
>>
>> When enabling display-fill-column-indicator in .dir-locals.el, is it
>> possible to dynamically set display-fill-column-indicator-character
>> according to what characters are displayable without using eval?
>
> I don't think so.

Thank you!!