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Re: Behavior of evaporate
From: |
David Kastrup |
Subject: |
Re: Behavior of evaporate |
Date: |
26 Sep 2003 11:17:24 +0200 |
User-agent: |
Gnus/5.09 (Gnus v5.9.0) Emacs/21.3.50 |
Masatake YAMATO <address@hidden> writes:
> > > > I was thinking of suggesting that but wasn't sure whether it'd work.
> > > > Does it ? If it does, it's probably the simplest alternative, indeed.
> > >
> > > `evaporate' doesn't work I expect. So I introduced suboverlays
> > > property to manage overlay deletion.
> >
> > I'm not sure exactly what you're saying, but the overlay
> > `evaporate' feature definitely works (unless it's recently been
> > broken)...
>
> (progn (setq xxx 1)
> (setq o (make-overlay 0 0))
> (overlay-put o 'modification-hooks (lambda (ov dummy b e l)
> (setq xxx 0)))
> (overlay-put o 'evaporate t)
> xxx)
> => 1
>
> Result I expected is 0.
> So I can know an overlay is dead.
> Do I misunderstand?
Yes. From the manual:
`evaporate'
If this property is non-`nil', the overlay is deleted automatically
if it ever becomes empty (i.e., if it spans no characters).
But the overlay does not become empty in your example. It _is_
already empty.
Setting the overlay borders explicitly is not what this property is
useful for catching. It is there for the case that the overlay
becomes empty by side effect. Try
(progn (setq xxx 1)
(goto-char 1)
(insert "x")
(setq o (make-overlay 1 2))
(overlay-put o 'modification-hooks (list (lambda (ov dummy b e
&optional l)
(setq xxx 0))))
(overlay-put o 'evaporate t)
(delete-char 1)
xxx)
And notice that modification-hooks takes a list of functions, not
just a single function. And that the last argument of the function
is optional.
--
David Kastrup, Kriemhildstr. 15, 44793 Bochum
- Re: popup menu support for smerge-mode, Masatake YAMATO, 2003/09/18
- Re: popup menu support for smerge-mode, Stefan Monnier, 2003/09/18
- Re: popup menu support for smerge-mode, Masatake YAMATO, 2003/09/19
- Re: popup menu support for smerge-mode, Stefan Monnier, 2003/09/19
- Re: popup menu support for smerge-mode, Masatake YAMATO, 2003/09/26
- Re: popup menu support for smerge-mode, Miles Bader, 2003/09/26
- Behavior of evaporate, Masatake YAMATO, 2003/09/26
- Re: Behavior of evaporate, Miles Bader, 2003/09/26
- Re: Behavior of evaporate,
David Kastrup <=
- Re: Behavior of evaporate, Stefan Monnier, 2003/09/26
- Re: Behavior of evaporate, Richard Stallman, 2003/09/26
- Re: Behavior of evaporate, Alex Schroeder, 2003/09/30