Re: `vertical-motion', `goto-line' set point to invisible text

[Dmitry Kurochkin <dmitry.kurochkin@gmail.com>]

On Sun, 03 Jul 2011 16:33:54 +0300, Eli Zaretskii <eliz@gnu.org> wrote:
> > From: Dmitry Kurochkin <dmitry.kurochkin@gmail.com>
> > Cc: emacs-devel@gnu.org
> > Date: Sun, 03 Jul 2011 11:31:23 +0400
> > 
> > Is there a way to ask Emacs to sync point to visible position, so
> > that I do not have to do it by hand?
> 
> Not sure what that means.  Can you explain more about what you are
> looking for?
> 

I am looking for a function that does something like what you described
below.  I.e. moves point to the next suitable character in the given
direction.  At the moment I do it with smth like:

  ;; if point is invisible, skip forward to visible text
  (while (invisible-p p)
    (setq p (next-single-char-property-change p 'invisible)))

> > I.e. M-: (progn (backward-char) (point)) works fine.  But after that
> > M-: (point) returns another position which corresponds to the
> > beginning of the hidden line.  I guess this has to do command loop I
> > know nothing about.
> 
> When a command finishes and Emacs is idle (i.e. has nothing else to
> do), it examines the position of point.  If it finds that point is on
> some character where it shouldn't be, it moves point to the next
> "suitable" character in the direction of last move.  Text where point
> shouldn't be includes: invisible text, non-base character that belongs
> to a composed character, and text covered by a "replacing" `display'
> property.
> 

Thanks for the detailed explanation.

> > IMO Emacs should not touch the point in this case, because it is
> > already visible.  Sounds like a bug to me.
> 
> If no one comes up with a plausible explanation until tomorrow, feel
> free to submit a bug report.
> 

ok

> Btw, I just tried past releases, and Emacs 21.4 didn't have this
> problem, but Emacs 22.3 did.  I guess that's a side effect of point
> adjustment described above, which Emacs 21.4 didn't have: in Emacs
> 21.4, the cursor stays put for several C-f or C-b commands, as long as
> point is on invisible text.

I will put a reference in the bug report.

Regards,
  Dmitry