Re: Outline mode

[Stefan Monnier]

> Outline-mode has a problem that I would like to fix.  To see the
> problem, hide an entry (C-c C-c) in an outline-mode buffer, and put
> point at the end of the heading with C-e.  Point will then be located
> to the right of the ellipsis, and as far as emacs knows, point is on
> the last line of the hidden entry.  Typing characters or hitting
> backspace, and many other commands will affect the last line of the
> entry.

Yes.  That's a known shortcoming in the redisplay engine: the cursor should
be drawn to the left of the ellipsis to better reflect the position of point.

> When an entry is collapsed in outline-mode, what actually gets marked
> invisible is everything from the newline of the heading to the
> character before the final newline of the entry.  It would make more
> sense, if the newline of the heading were left visible, and the final
> newline of the entry were hidden.  The ellipsis can be placed in the
> buffer by using the 'display property on the newline of the heading.

I don't think that's a good idea in general: it forces every entry to span
at least two display lines: one for the heading and another for the
ellipsis.  In some contexts it might be accpetable, but definitely
not always.

> However, there is a large problem with fixing outline-mode.  The
> problem is that many of the modes that derive their behavior from
> outline-mode probably depend on the current way that entries are
> hidden.  I am hoping that I can get advice from more experienced emacs
> developers on how to go about this project.  I am also hoping to get
> help from the maintainers of as many of the derived modes as possible.

Maybe you could make it an option.


        Stefan