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

20 May 2006

      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))))

With this and my fileevent stuff I can now say:

;; Model for a simple terminal output window.

(defmodel fileevent-test-window (window)
   ()
   (:default-initargs
       :kids (c? (the-kids
		   (mk-stack (:packing (c?pack-self))
		     (mk-label :text "Receive window"
			       :pady 10)
		     (mk-text-widget :id :receive-window
				     ;:state 'disabled
				     :md-value (c-in "")
				     :height 10
				     :width 80
				     :borderwidth 2
				     :relief 'sunken
				     :pady 5))
		   (mk-fileevent :id :fileevent-test
				 :read-fn 'read-from-pipe
			         :iostream (open "/Users/frgo/tmp/frgo-test"
					         :direction :input))))))

;; The method read-from-pipe reads data from a pipe generated by
;; mkfifo /Users/frgo/tmp/frgo-test and puts this as the data of a
;; text widget

(defmethod read-from-pipe ((self tk-fileevent) &optional  
(operation :read))
   (declare (ignorable operation))
   (let ((stream (^iostream)))
     (let ((data (read-line stream nil nil nil)))
       (trc "*** READ-FROM-PIPE: data = " data)
       (when data
         (setf (md-value (fm-other :receive-window)) data))))
)

;; Test function that fires up the test case

(defun test-fileevent ()
   (trc  
"----------------------------------------------------------------------- 
------")
   (test-window 'fileevent-test-window)
   (trc  
"----------------------------------------------------------------------- 
------")
)

Now, whenever I do a

$ echo "Heya this is a test" > /Users/frgo/tmp/frgo-test

the text gets displayed in the window. Of course there's other uses  
for this:
You also can open a socket and send application commands to the  
application. The read-from-pipe function would then be a little  
interpreter kicking of actions in the application...

For me I put the reading function to listen to a RS232C port that is  
connected to an AVR-based microcontroller. The controller send status  
information and voltage and current values from a power supply to be  
displayed as info by my application...

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

Frank