Widgets and text-changing

Widgets and text-changing

[Stephen Berman]

Is it possible to apply text-changing commands or functions to widgets
in a buffer without dewidgetizing them?  For example, if I eval this
sexp:

    (with-current-buffer (get-buffer-create "*Widget Test*")
      (setq mylist '("delta" "alfa" "charlie" "bravo"))
      (switch-to-buffer (current-buffer))
      (erase-buffer)
      (kill-all-local-variables)
      (mapc (lambda (elt)
	      (widget-create 'push-button
			     :notify (lambda (&rest ignore) (message "Test"))
			     elt)
	      (widget-insert "\n"))
	    mylist)
      ;; (sort-lines nil (point-min) (point-max))
      (use-local-map widget-keymap)
      (widget-setup))

then the buffer *Widget Test* contains these widgets, which are in bold
face, have mouse-face highlighting, and are active (clicking them
displays the message "Test"):

    [delta]
    [alfa]
    [charlie]
    [bravo]

If I now try to modify this buffer, e.g. with sort-lines, this fails
with the error:

widget-before-change: Text is read-only: "Attempt to change text outside
editable field"

If I uncomment the commented line in the above sexp and eval it again,
then the lines in *Widget Test* are alphabetized:

    [alfa]
    [bravo]
    [charlie]
    [delta]

but dewidgetized: no bold face, no hightlighting, not active.

Is it possible to manipulate, e.g. sort, widgets in a buffer without
them losing their widgetry?

Steve Berman

Re: Widgets and text-changing

[MON KEY]

Stephen Berman <stephen.berman@gmx.net> writes:

> Is it possible to apply text-changing commands or functions to widgets
> in a buffer without dewidgetizing them?  For example, if I eval this
> sexp:
>
>     (with-current-buffer (get-buffer-create "*Widget Test*")
>       (setq mylist '("delta" "alfa" "charlie" "bravo"))
> {...}
> Is it possible to manipulate, e.g. sort, widgets in a buffer without
> them losing their widgetry?

I'm sure this was obvious and I don't intend any sarcasm, but what about:

(setq mylist '(sort '("delta" "alfa" "charlie" "bravo") 'string<)

> Steve Berman

s_P

Re: Widgets and text-changing

[MON KEY]

> (setq mylist '(sort '("delta" "alfa" "charlie" "bravo") 'string<)

er... double quoted that list :(

      (setq mylist (sort '("delta" "alfa" "charlie" "bravo") 'string<))

Re: Widgets and text-changing

[Stephen Berman]

On Thu, 18 Jun 2009 16:02:43 -0400 MON KEY <monkey@sandpframing.com> wrote:

> Stephen Berman <stephen.berman@gmx.net> writes:
>
>> Is it possible to apply text-changing commands or functions to widgets
>> in a buffer without dewidgetizing them?  For example, if I eval this
>> sexp:
>>
>>     (with-current-buffer (get-buffer-create "*Widget Test*")
>>       (setq mylist '("delta" "alfa" "charlie" "bravo"))
>> {...}
>> Is it possible to manipulate, e.g. sort, widgets in a buffer without
>> them losing their widgetry?
>
> I'm sure this was obvious and I don't intend any sarcasm, but what about:
[...]
> (setq mylist (sort '("delta" "alfa" "charlie" "bravo") 'string<)

This is fine as far as it goes, though in my specific use case it has to
be a bit more complicated, since I need to both preserve the initial
list and do case insensitive sorting.  This added complication is what
prompted my post, since if it were possible to apply text-changing
functions to widgetized buffers, I would only need to set sort-fold-case
and call sort-lines.  But since this apparently is not possible, I have
indeed resorted to the pre-sorting, despite its additional slight
overhead.

Steve Berman

Re: Widgets and text-changing

[MON KEY]

On Fri, Jun 19, 2009 at 8:56 AM, Pierre
Lorenzon<devel@pollock-nageoire.net> wrote:
>  buffer after it has been sorted ? First bind the
>  buffer-read-only variable to nil to allow sort-lines which is
>  meant to rewrite the buffer for instance :
>  (let ((buffer-read-only nil))
>    (sort-lines)
>    (widget-setup))
>

Before responding I had tried Stephen's example with a

 (setq inhibit-read-only t)

this alone didn't help.

Is this because there are overlays in effect not (just/only) text-props?

I didn't go any further setting additional buffer variables, but it
may be that a larger set of inhibitions is required (and perhaps
others as well) i.e. temporarily setting:

 (setq inhibit-read-only t
         inhibit-point-motion-hooks t
         inhibit-modification-hooks t)

This sort of approach works works with text-properties (and I have no
idea how it corelates with the widget library)

Would an alternative approach be to forgo the initial widget-insert
and assign text-properties on the buffer contents with the help of
some regexps and only widgetize according to a prop val once the
buffer's setup is finalized?

This prob. moves quite a bit further out from the OP intentions and
may well over complicate  what widgets were intended to simplify :{

s_P