[ltk-user] Another newbie question..

[Neil Baylis]

Thanks Peter, that makes sense. I guess I didn't understand dynamic
scope as well as I had thought.

I changed the code inside the (let* ...) as follows, and this works:

(defun testit ()
  (with-ltk ()
    (let* ((canv (setf *cvs* (make-instance 'canvas :width 200 :height 200)))
	   (b (make-instance 'button
			     :master nil
			     :text "Do it!"
			     :command (lambda ()
					(draw-circle 100 100 20 :red)))))

      (format t "A Canvas is ~a~%" *cvs*)
      (pack canv)
      (pack b)
      (draw-circle 100 100 40 :blue))))

This makes it more obvious (to me..) that the canvas bound inside the
(let*...) is different from the global one. I guess this is how the
ltk::ltktest example is able to work, e.g. the start and stop buttons.

I bet this wont be the last time I am bitten by that problem.

Thanks,

Neil