Re: Overlay before-string property

[David Kastrup]

"Drew Adams" <address@hidden> writes:

>     > I use this, from Miles Bader's minibuf-depth.el (or whatever
>     > it's called now):
>     >
>     > ;; This function goes on minibuffer-setup-hook
>     > (defun minibuf-depth-setup-minibuffer ()
>     >   "Set up a minibuffer for `minibuffer-indicate-depth-mode'.
>     > The prompt should already have been inserted."
>     >   (when (> (minibuffer-depth) 1)
>     >     (setq minibuf-depth-overlay
>     >           (make-overlay (point-min) (1+ (point-min))))
>     >     (overlay-put minibuf-depth-overlay 'before-string
>     >                      (format "%d) " (minibuffer-depth)))
>     >     (overlay-put minibuf-depth-overlay 'evaporate t)))
>     >
>     > Does this have something to do with text-property stickiness? I have
>     > not knowingly changed any sticky properties, and the manual seems to
>     > say that text is, by default, only rear sticky. The behavior seems
>     > to be as if the prompt-string text were front-sticky and the overlay
>     > were rear-sticky, IIUC.
>
>     You could read the DOC string of make-overlay.  It has optional
>     arguments.
>
> Thanks, but I don't see how that helps. Perhaps I'm misreading it or
> the text has changed since July (my build), however. It speaks of
> FRONT-ADVANCE and REAR-ADVANCE, but I don't see how that would be
> related to property stickiness. The manual says about the same thing
> as the doc string.

It is related to stickiness, but your description indeed made me do a
wrong guess.  This has nothing to do with stickiness, it simply has to
do with the overlay _covering_ the character in question.  Use
(make-overlay (point-min) (point-min))
instead.  It may be necessary to ise the 'display instead of the
'before-string property for this to work; I don't remember the
details.

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum