bug#4318: 23.1; trouble indenting looooong lines with visual-line-mode

bug#4318: 23.1; trouble indenting looooong lines with visual-line-mode

[Allan Gottlieb]

Please write in English if possible, because the Emacs maintainers
usually do not have translators to read other languages for them.

Your bug report will be posted to the bug-gnu-emacs@gnu.org mailing list,
and to the gnu.emacs.bug news group.

Please describe exactly what actions triggered the bug
and the precise symptoms of the bug:

Start with emacs -Q and a buffer in fundamental mode

Consider a line wider than the frame, for example

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

which exceeds an 80 column frame.
Now assume you have a short line say
yyyy
followed by the above long line, i.e.
yyyy
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

So far so good.  Now indent the long line with say one space.
If visual-line-mode is OFF, I see what I expect, the long line is
preceded by one space.

But with visual-line-mode ON, a blank line appears on the screen between
the short and long lines, i.e. the long line (with only one word) was
wrapped.
This behavior seems wrong.
I realize the blank line is not in the file, but believe the on-screen
image is misleading or at least annoying.

Thanks for emacs.
allan <gottlieb@nyu.edu>


If Emacs crashed, and you have the Emacs process in the gdb debugger,
please include the output from the following gdb commands:
    `bt full' and `xbacktrace'.
If you would like to further debug the crash, please read the file
/usr/share/emacs/23.1/etc/DEBUG for instructions.


In GNU Emacs 23.1.1 (i686-pc-linux-gnu, GTK+ Version 2.14.7)
 of 2009-08-17 on ajglap
Windowing system distributor `The X.Org Foundation', version 11.0.10503000
configured using `configure  '--prefix=/usr' '--build=i686-pc-linux-gnu' '--host=i686-pc-linux-gnu' '--mandir=/usr/share/man' '--infodir=/usr/share/info' '--datadir=/usr/share' '--sysconfdir=/etc' '--localstatedir=/var/lib' '--program-suffix=-emacs-23' '--infodir=/usr/share/info/emacs-23' '--with-sound' '--with-x' '--with-toolkit-scroll-bars' '--with-gif' '--with-jpeg' '--with-png' '--without-rsvg' '--with-tiff' '--with-xpm' '--with-xft' '--without-libotf' '--without-m17n-flt' '--with-x-toolkit=gtk' '--without-hesiod' '--without-kerberos' '--without-kerberos5' '--with-gpm' '--with-dbus' 'build_alias=i686-pc-linux-gnu' 'host_alias=i686-pc-linux-gnu' 'CFLAGS=-O2 -march=prescott -pipe' 'LDFLAGS=-Wl,-O1''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: nil
  value of $XMODIFIERS: nil
  locale-coding-system: nil
  default-enable-multibyte-characters: t

Major mode: Article

Minor modes in effect:
  iswitchb-mode: t
  delete-selection-mode: t
  tooltip-mode: t
  mouse-wheel-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  global-auto-composition-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
M-x a j g SPC i n i t <return> M-x g n u s <return> 
<return> <down> <down> <down> SPC E SPC <help-echo> 
<select-window> <help-echo> <select-window> <help-echo> 
<select-window> <select-window> q <down> <return> <C-end> 
C-r - > <return> <return> <help-echo> <help-echo> <select-window> 
<help-echo> <select-window> <select-window> <select-window> 
<help-echo> <help-echo> <select-window> ! d ! <select-window> 
<select-window> C-x 5 2 <switch-frame> <switch-frame> 
<select-window> <help-echo> <help-echo> M-x r e p o 
r t - e m <tab> <return>

Recent messages:
Fetching headers for nnml:MAIL...done
Finding all score files...done
Generating summary...done
Retrieving newsgroup: nnml:emacs...
Fetching headers for nnml:emacs...done
Scoring...done
Generating summary...done
Mark set
Mark saved where search started
Auto-saving...done

bug#4318: 23.1; trouble indenting looooong lines with visual-line-mode

[Lars Magne Ingebrigtsen]

Allan Gottlieb <gottlieb@nyu.edu> writes:

> yyyy
> xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>
> So far so good.  Now indent the long line with say one space.
> If visual-line-mode is OFF, I see what I expect, the long line is
> preceded by one space.
>
> But with visual-line-mode ON, a blank line appears on the screen between
> the short and long lines, i.e. the long line (with only one word) was
> wrapped.
> This behavior seems wrong.

I can confirm this behaviour in Emacs 24.

The problem seems to be that `visual-line-mode' breaks long lines after
any white space -- even if the white space begins the line.  That
doesn't seem optimal, I think.

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

bug#4318: 23.1; trouble indenting looooong lines with visual-line-mode

[Eli Zaretskii]

> From: Lars Magne Ingebrigtsen <larsi@gnus.org>
> Date: Sat, 17 Sep 2011 09:23:14 +0200
> Cc: 4318@debbugs.gnu.org
> 
> Allan Gottlieb <gottlieb@nyu.edu> writes:
> 
> > yyyy
> > xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> >
> > So far so good.  Now indent the long line with say one space.
> > If visual-line-mode is OFF, I see what I expect, the long line is
> > preceded by one space.
> >
> > But with visual-line-mode ON, a blank line appears on the screen between
> > the short and long lines, i.e. the long line (with only one word) was
> > wrapped.
> > This behavior seems wrong.
> 
> I can confirm this behaviour in Emacs 24.
> 
> The problem seems to be that `visual-line-mode' breaks long lines after
> any white space -- even if the white space begins the line.  That
> doesn't seem optimal, I think.

The extra line stands for the space that is not shown.  If you place
the cursor on that "empty line" and type "C-x =", you will see that
point is before the space character, not before newline.

So I think visual-line-mode (a.k.a. "word wrap") behaves correctly.
Doing what the OP asks for would also have undesirable side effects,
albeit different ones.  E.g., adding some non-white character at the
beginning of that line will suddenly and mysteriously move the
"xxxx..." part one line down.

And that's even before I consider the potential complications of the
code, which already tracks the word wrap mode with no less than 12
state variables...

My recommendation is to close this bug as "won't fix".

bug#4318: 23.1; trouble indenting looooong lines with visual-line-mode

[Lars Magne Ingebrigtsen]

Eli Zaretskii <eliz@gnu.org> writes:

> The extra line stands for the space that is not shown.  If you place
> the cursor on that "empty line" and type "C-x =", you will see that
> point is before the space character, not before newline.
>
> So I think visual-line-mode (a.k.a. "word wrap") behaves correctly.
> Doing what the OP asks for would also have undesirable side effects,
> albeit different ones.  E.g., adding some non-white character at the
> beginning of that line will suddenly and mysteriously move the
> "xxxx..." part one line down.

I think that's probably desired.

The point of `visual-line-mode' is to (visually) do word wrap between
words to keep lines short(ish).  Folding before there even has been a
word looks odd to me.

On the other hand, it does make the lines visually shorter, so it's
debatable...

> And that's even before I consider the potential complications of the
> code, which already tracks the word wrap mode with no less than 12
> state variables...

:-)

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

bug#4318: 23.1; trouble indenting looooong lines with visual-line-mode

[Chong Yidong]

Eli Zaretskii <eliz@gnu.org> writes:

>> The problem seems to be that `visual-line-mode' breaks long lines after
>> any white space -- even if the white space begins the line.  That
>> doesn't seem optimal, I think.
>
> The extra line stands for the space that is not shown.  If you place
> the cursor on that "empty line" and type "C-x =", you will see that
> point is before the space character, not before newline.
>
> So I think visual-line-mode (a.k.a. "word wrap") behaves correctly.

It's different from what other word-wrapping editors do, so I think this
should be considered a bug.

bug#4318:

[GMNT p8]

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Hello,
we just started to work on this issue, if you have any tips or advices that
aren't in the report yet about how to solve it, they are welcome.

Thanks in advance.
Cheers

-GMNT

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