(defpackage rsvp
  (:use :cl :cl-ppcre :ltk)
  (:export :app))

(in-package :rsvp)

(defvar *action* nil)

(defvar *counter* 0)

(defun app()
  (with-ltk()
    (let* ((toggle (make-instance 'button
				:width 10
				:command (lambda()
                                           (setf *action* (not *action*)))
				:text "Toggle"))
          (canvas (make-instance 'canvas
                                 :height 200
                                 :width 200)))
      (pack canvas)
      (pack toggle)
      (bind canvas "<Motion>"
            (lambda(evt)
              (when *action*
		(let ((text (create-text canvas 50 50 (write-to-string
                                                       (incf *counter*)))))
                  (clear canvas)
                  (format t "~a~%" *counter*)
                  (sleep 1)))))
      (loop
         (process-events)))))