[cells-devel] Re: Celtk: setting the content of a text widget ? Fileevent working !

[Ken Tilton]

On 5/20/06, Frank Goenninger <fgoenninger at prion.de> wrote:
>
>
> Am 20.05.2006 um 20:16 schrieb Frank Goenninger:
>
> > Am 20.05.2006 um 18:24 schrieb Ken Tilton:
> >
> >> Frank Goenninger wrote:
> >>
> >>> Hi Kenny, hi all:
> >>>
> >>> I do have a text widget which is created using mk-text-widget:
> >>>
> >>> (mk-text-widget :id :receive-window
> >>>                  :state 'disabled
> >>>                  :md-value (c?n "...")
> >>>                  :height 10
> >>>                  :width 80
> >>>                  :borderwidth 2
> >>>                  :relief 'sunken
> >>>                  :pady 5))
> >>>
> >>> No matter what I do (even setting :state to 'enabled) I do get
> >>> anything printed in the text widget.
> >>>
> >>> I actually execute a setf on md-value of the text widget:
> >>>
> >>> (setf (md-value (fm-other :receive-window)) data)
> >>>
> >>>
> >>> Any idea? Thx!
> >>
> >>
> >> Hmmm, looks like I did not finish implementing text widgets.
> >
> > Yep, meanwhile I recognized that an observer is missing in file
> > entry.lisp.
>
> Well, actually I had to do (in file entry.lisp):
>
> ;; Method CLEAR: clears a text widget to zero content
>
> (defmethod clear ((self text-widget))
>    (tk-format `(:variable ,self) "~a delete 1.0 end" (^path)))
>
> ;; This observer puts text to the widget if md-value has been set
> ;; Also takes care of edge cases like initialization time and setting
> ;; strings of length 0...
>
> (defobserver .md-value ((self text-widget))
>    (trc "md-value output" self new-value)
>    (if (or (and (not old-value)
>                (string= new-value ""))
>           (not new-value))
>      (tk-format `(:variable ,self) "~a delete 1.0 end" (^path))
>      (if (> (length new-value) 0)
>        (tk-format `(:variable ,self) "~a insert end ~a" (^path) new-
> value))))


I took your stuff and whittled it down to:

(defobserver .md-value ((self text-widget))
  (trc "md-value output" self new-value)
  (with-integrity (:client `(:variable ,self))
    (tk-format-now "~a delete 1.0 end" (^path))
    (when (plusp (length new-value))
      (tk-format-now "~a insert end ~s" (^path) new-value))))

That way two (setf (md-value self) "Hi mom") calls do not produce "Hi momHi
mom".

I was not sure  the API entry point CLEAR was needed elsewhere. I can see
that it would be, though. Really, the more I look at the text widget  the
more I think it needs imperative processing by application code that has a
clear idea of what it wants to do with all the capabilities of the widget.

I also brought both commands within the same integrity bundle by skipping
the tk-format syntactic sugar and open-coding with-integrity. That just
saves one enqueue, no big deal. A bigger deal is that the sort done by
tk-user-queue-handler was not (until just now <g>) a stable sort, so the
delete could have been executed after the insert. Bringing both operations
into the single integrity bundle also fixes that.


>
> Now, whenever I do a
>
> $ echo "Heya this is a test" > /Users/frgo/tmp/frgo-test
>
> the text gets displayed in the window.


Isn't great when we get stuff like that working? Is there a universal law:
any time the effect produced by your own code surprises you, you are
probably onto something good. Programming never gets old.


> Fileevent to be put to Celtk CVS in a few days ... watch out.


Thx. I am switching all my code to LLGPL now, btw. I think we settled on
that for your stuff, yes?

kt
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