------------------
To run the sample:
------------------
At the Lisp prompt:

USER> :ld defsystem 	;; Load demo file - takes awhile for Tcl/Tk libraries to load.
USER> (load-system :tkdemo)	;; You'll probably want to save an image with the
				;; libraries pre-loaded.

<... Loading messages left out ... >

USER> :pa tcltk     ;; Go to the Tk package 

TCLTK> (demo)       ;; Run the program - two buttons & a label.
NIL		    ;;
	            ;; Hello opens a pseudo "Lisp listener"
		    ;;   Type a form in the "Expression" window.
		    ;;   Type <control-x> or push "Eval" to evaluate it.
		    ;;      (Only the first form in the window is eval'ed.)
		    ;;   The return value is put in the "Result" window.
		    ;;   Type <control-c> to or push "Clear" to clear a window.
		    ;;   Push Quit to close the listener.
		    ;; Errors are caught and only return nil.
		    ;; Bye closes everything down.

TCLTK> (trace tkeval)  ;; To see what's actually being sent to the tcl intepreter.
		    ;; tkeval returns 0 on successful command execution.

;;;----------------------------------------------------------------
;;; You can do the normal things you would expect in an interpreted 
;;; environment.
;;;----------------------------------------------------------------
TCLTK> (Tkcmd *interp* ".bye" 'configure :background 'red)
""
TCLTK> (dotimes (i 3) (Tkcmd *interp* ".bye" 'flash))
NIL

;;;----------------------------------------------------------------
;;; Redefine a callback - don't have to re-register as long as you 
;;; use the same name. 
;;;----------------------------------------------------------------
TCLTK> (def-tcl-command say-bye ()
          (apropos 'bye))
SAY-BYE

;;;----------------------------------------------------------------
;;; Delete a button.
;;;----------------------------------------------------------------
TCLTK> (Tkcmd *interp* 'destroy ".bye")
""
;;;----------------------------------------------------------------
;;; If you destroy the "Bye" button, type (shutdown) to manually
;;; close everything, then (demo) to restart.
;;;----------------------------------------------------------------

;;; etc ...


 