Re: Cursor positioning with `after-string' overlays

[Eli Zaretskii <eliz@gnu.org>]

> Date: Fri, 02 Apr 2010 10:53:11 +0300
> From: Eli Zaretskii <eliz@gnu.org>
> Cc: emacs-devel@gnu.org
> 
> > From: storm@cua.dk (Kim F. Storm)
> > Cc: emacs-devel@gnu.org
> > Date: Thu, 01 Apr 2010 23:54:16 +0200
> > 
> > CUA rectangle mode may use the old behaviour to place cursor midway
> > through a tab character - I cannot judge from your example if that
> > is still working with the trunk code, and I don't have time to check
> > one out (I got lost in the Bazaar)...
> > 
> > But you can easily try it out.
> > Just enter:
> > 
> > M-x cua-mode RET
> > a C-q C-i b
> > C-a C-RET C-f C-f C-f ..
> > 
> > cursor should move successively from a through the tab until it reaches b
> 
> You are right, it doesn't work.  But it doesn't work in Emacs 23.1 and
> in Emacs 22.3, either, at least not on MS-Windows and on GNU/Linux.
> 
> Are you sure the recipe is correct?  If so, in what version of Emacs
> did it work for you?

I think I see the answer.  The recipe should be modified like this:

 M-x cua-mode RET
 a C-q C-i b RET
 C-p C-RET C-f C-f C-f ..

That is, there should be a newline after `b'.  When modified like
this, I see the expected behavior both with the current trunk and with
older versions.

Is this satisfactory?

Note that what cua-rect.el does differs from the example I posted in
one crucial aspect: cua-rect.el uses an integer number, rather than
just `t', for the value of the `cursor' property.  This number
actually tells the cursor-positioning code for which buffer positions
we should display the cursor on the character that has this property.
When the `cursor' property has an integer value, it really does
override the ``exact match for point always wins'' strategy, for
buffer positions that are ``covered'' by the value of `cursor'.