anchor.diff:     #:get-opts
      #:describe
      #:make-options
  -
  -   ;; Symbols
  -   #:not-given
   
      ;; Macros
      #:define-opts)
  
positive.code: to `nil')"
    (do ((tokens (mapcan #'split-short-opts
                         (mapcan #'split-on-=
                                 (if (eq options 'not-given)
                                     (cdr (argv))
                                     options)))
                 (cdr tokens))
         (required (map-options-to-hash-table defined-options #'required))
         (default-values (map-options-to-hash-table defined-options #'default))
  
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.
  