bug#35338: Line numbers lost despite line-number-display-limit

bug#35338: Line numbers lost despite line-number-display-limit

[積丹尼 Dan Jacobson]

We read

   line-number-display-limit is a variable defined in ‘C source code’.
   Its value is nil

   Documentation:
   Maximum buffer size for which line number should be displayed.
   If the buffer is bigger than this, the line number does not appear
   in the mode line.  A value of nil means no limit.

$ perl -wle 'print "中華民國萬歲" x 99 for 9..99;' >| /tmp/9
$ wc /tmp/9
    91     91 162253 /tmp/9
$ emacs -nw -q /tmp/9
C-v
C-v
C-v...

About halfway through the file it loses track of the line number, which
becomes "L??". No value of LC_ALL will help either.

bug#35338: Line numbers lost despite line-number-display-limit

[Eli Zaretskii]

> From: 積丹尼 Dan Jacobson
> 	<jidanni@jidanni.org>
> Date: Sat, 20 Apr 2019 14:33:30 +0800
> 
> $ perl -wle 'print "中華民國萬歲" x 99 for 9..99;' >| /tmp/9
> $ wc /tmp/9
>     91     91 162253 /tmp/9
> $ emacs -nw -q /tmp/9
> C-v
> C-v
> C-v...
> 
> About halfway through the file it loses track of the line number, which
> becomes "L??". No value of LC_ALL will help either.

Does "C-h f line-number-display-mode RET" tell something that helps to
understand what's going on?

bug#35338: Line numbers lost despite line-number-display-limit

[Eli Zaretskii]

> From: 積丹尼 Dan Jacobson
> 	<jidanni@jidanni.org>
> Date: Sat, 20 Apr 2019 14:33:30 +0800
> 
> $ perl -wle 'print "中華民國萬歲" x 99 for 9..99;' >| /tmp/9
> $ wc /tmp/9
>     91     91 162253 /tmp/9
> $ emacs -nw -q /tmp/9
> C-v
> C-v
> C-v...
> 
> About halfway through the file it loses track of the line number, which
> becomes "L??". No value of LC_ALL will help either.

Does "C-h f line-number-mode RET" tell something that helps to
understand what's going on?

(In the previous mail I mistakenly used line-number-display-mode;
sorry for the typo.)

bug#35338: Line numbers lost despite line-number-display-limit

[積丹尼 Dan Jacobson]

Users who do C-f v line-number-display-limit will never learn about
line-number-display-limit-width, and vice versa. 100%!

Therefore each docstring needs to mention the other.

Else the user won't know about the secret second hidden factor,
and will be sure it is a bug.

By the way, line-number-display-limit-width's docstring should say what
nil will do, and/or how to always/never get numbers.

P.S., "If the average length of the lines near point is bigger than
this, then the line number may be omitted from the mode line."

"near", "may" ??! Well all I know is if we do
$ { perl -wle 'print "中華民國萬歲" x 99 for 9..99;' ; seq 1111;} >  /tmp/9
we start out with fat lines, and then end up with thin lines,
and we get line numbers for the first few screens, and then it gives up.
If at the bottom we do (what-line) then it remembers again, until we go
back to the fat lines, where it forgets, even if we do (what-line).
Anyway I bet these days the rest of emacs' brain is actually rather
quite aware of what line we are actually on, and just this
line-number-display-limit-width is left over from some older era...
less -M and more's '=' have no problem.