anchor.diff:  to `nil')"
     (do ((tokens (mapcan #'split-short-opts
                          (mapcan #'split-on-=
  -                               (if (eq options 'not-given)
  -                                   (cdr (argv))
  -                                   options)))
  +                               (if options-supplied-p
  +                                   options
  +                                   (cdr (argv)))))
                  (cdr tokens))
          (required (map-options-to-hash-table defined-options #'required))
          (default-values (map-options-to-hash-table defined-options #'default))
  
positive.code:    #:get-opts
     #:describe
     #:make-options
  
     ;; Symbols
     #:not-given
  
     ;; Macros
     #:define-opts)
  
negative.code:           ((cadr matches) nil)
            (t (car matches)))))))
  
  (defun get-opts (&optional (options nil options-supplied-p) (defined-options *options*))
    "Parse command line options. If OPTIONS is given, it should be a list to
  parse. If it's not given, the function will use `argv' function to get list
  of command line arguments.
  