[emacs-w3m:06591] enabling evaporation of overlays

[emacs-w3m:06591] enabling evaporation of overlays

[Katsumi Yamaoka]

Hi,

This message is continued from the following thread:

http://thread.gmane.org/n05yv0h3.fsf@ID-23066.news.dfncis.de

>>>>> In [emacs-w3m : No.06589] Katsumi Yamaoka wrote:

> I also got a report from Hiroshi Fujishima yesterday that there
> is a problem in Gnus.  When a user types the `t' key in the
> summary buffer, mouse-face spreads over the whole article header.
> It is required that the value for gnus-treat-buttonize-head is
> `head' (which is the default).  I haven't investigated it yet,
> though.

The problem arises since it is the middle of the development of
overlay functions in the Emacs CVS head.  It can be fixed by the
following code:

(eval-after-load "gnus"
  '(progn
     (defun gnus-make-overlay (&rest args) "\
Run `make-overlay' and enable the `evaporate' property on overlay."
       (let ((overlay (apply 'make-overlay args)))
	 (overlay-put overlay 'evaporate t)
	 overlay))
     (require 'byte-comp)
     (byte-compile 'gnus-make-overlay)))

It is useful that all overlays made by Gnus will be vanished
when `erase-buffer' is performed.  However, currently I don't
want to install it to Gnus CVS.  Because it doesn't affect
overlays made for widget buttons and we are unable to abolish
the gnus-kill-all-overlays function.  Furthermore, I heard
Masatake YAMATO is planning to enable evaporation of all
overlays by default.  All problems will be solved if it is
realized.

Regards,
-- 
Katsumi Yamaoka <yamaoka@jpl.org>

[emacs-w3m:06592] Re: enabling evaporation of overlays

[Masatake YAMATO]

Yamaoka-san wrote:
> I heard
> Masatake YAMATO is planning to enable evaporation of all
> overlays by default.  All problems will be solved if it is
> realized.

The idae is rejected but another idea is suggested by RMS in emacs-devel:

	How do you think make evaporate overlay's property t by default(when make-overlay)?

    That would break many programs.  It is the wrong solution.

    I think the right fix is in fix_start_end_in_overlays.  When an
    insertion occurs next to an overlay whose beginning-marker is the
    advancing kind and whose end-marker is not, the overlay should stay
    empty.

I will follow this idea.

Masatake YAMATO

Fwd: Re: enabling evaporation of overlays

[Katsumi Yamaoka]

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From: Masatake YAMATO <jet@gyve.org>
To: yamaoka@jpl.org
Cc: ding@gnus.org, mi-ew3m@imarko.dhs.org, matt@stchem.bham.ac.uk, emacs-w3m@namazu.org
Subject: Re: enabling evaporation of overlays
Date: Thu, 08 Apr 2004 12:57:39 +0900 (JST)
Message-ID: <20040408.125739.44572072.jet@gyve.org>

Yamaoka-san wrote:
> I heard
> Masatake YAMATO is planning to enable evaporation of all
> overlays by default.  All problems will be solved if it is
> realized.

The idae is rejected but another idea is suggested by RMS in emacs-devel:

	How do you think make evaporate overlay's property t by default(when make-overlay)?

    That would break many programs.  It is the wrong solution.

    I think the right fix is in fix_start_end_in_overlays.  When an
    insertion occurs next to an overlay whose beginning-marker is the
    advancing kind and whose end-marker is not, the overlay should stay
    empty.

I will follow this idea.

Masatake YAMATO

[emacs-w3m:06593] Re: enabling evaporation of overlays

[Masatake YAMATO]

Setting t to evaporate by default is rejected but RMS write 
this should be done by each application. After thinking I agree
with this. I start to discuss abut how to deal evaporate of widget's
overlay in emacs-devel.

RMS wrote in emacs-devel:
	I'd just like to add that mh-e also has this problem when displaying
	mime buttons and parts.  It was fixed by setting the overlay 'evaporate
	property to t.

	In any case it seems like a change for the better.  Previously all the
	gui-button faces would shrink to zero-length overlays and remain there,
	invisible, when the buffer contents were deleted and new contents
	inserted.  I now see that a lot of overlays accumulated after may reuses
	of the same buffer.

    It sounds like THESE overlays should be set to evaporate.
    But I think MH-E should do that.  I cc'd the MH-E maintainer.


Masatake YAMATO