anchor.diff:  (in-package :clox)
  +
  +(defparameter *debug* t)
   
   (defparameter +command-line-spec+
     '((("help" #\h #\?) :type boolean :optional t :documentation "Show help.")
       (("verbose" #\v) :type boolean :optional t :documentation "Become verbose, whatever it means.")))
  +
  +(defun quit (&optional (code 0))
  +  (if *debug*
  +      (error "I would quit now.")
  +      (uiop:quit code)))
   
   (defun main ()
     (handle-command-line
  
positive.code: 
  (-> run (string) null)
  (defun run (source)
    (loop for token in (scan-tokens source)
       do (format t "~A~%" token))
    (when (had-error)
      (uiop:quit -1))
    nil)
  
negative.code:       ((> args-len 1) (clox-help))
        ((= 1 args-len) (run-file (first args)))
        (t (run-prompt))))
    (quit)
    nil)
  
  (-> clox-help () null)
  (defun clox-help ()
    (show-option-help +command-line-spec+ :sort-names t)
    (quit)
    nil)
  
  (-> run-file (string) null)
  