bug#56820: outline-minor-mode replacing the first character with an arrow

[Eli Zaretskii]

> From: Juri Linkov <juri@linkov.net>
> Cc: yilkalargawworkneh@gmail.com,  larsi@gnus.org,  56820@debbugs.gnu.org
> Date: Thu, 08 Sep 2022 20:39:24 +0300
> 
> >> I counted ~100 occurrences of display_line_numbers in xdisp.c.
> >> So I guess display_outlines could be added based on code
> >> for display_line_numbers using the same strategy as
> >> tab_line was added based on header_line.
> >> 
> >> If this is a good idea, I could look into doing this
> >> after finishing all already opened issues, probably
> >> around December.
> >
> > I don't think I understand what you mean by "same strategy" here, so I
> > cannot answer the question yet.
> >
> > Vdisplay_line_numbers is used in xdisp.c for several purposes:
> >
> >   . adjust layout calculations for the space taken by line numbers
> >   . disable some redisplay optimizations that cannot be used when line
> >     numbers (especially relative numbers) are displayed
> >   . produce and display the line numbers for relevant lines
> >
> > Which one(s) are "strategy" for the purpose of this discussion?
> 
> The strategy is to reuse the existing code that adjusts layout calculations
> to display the line numbers, and to display outline arrows after line numbers.

So you are talking only about the first bullet above.