DouKaku?

(use srfi-37)
(use gauche.sequence)

(define (main args)
  (receive (debug output quiet rargv)
      (args-fold (cdr args)
                 (list
                  (option '(#\d "debug") #t #f
                          (lambda (option name arg debug output quiet argv)
                            (values (string->number arg) output quiet argv)))
                  (option '(#\o "output") #f #f
                          (lambda (option name arg debug output quiet argv)
                            (values debug #t quiet argv)))
                  (option '(#\q "quiet") #f #f
                          (lambda (option name arg debug output quiet argv)
                            (values debug output #t argv)))
                  )
                 (lambda (option name arg . _)
                   (error "Unrecognized option: " name))
                 (lambda (op debug output quiet argv)
                   (values debug output quiet (cons op argv)))
                 0 #f #f '())
    (cond
     ((not output)
      (format (current-error-port)
              "output option is not supplied.~%"))
     ((not (memv debug '(0 1 2)))
      (format (current-error-port)
              "debug option's value must be 0, 1, or 2: ~A~%" debug))
     ((null? rargv)
      (format (current-error-port)
              "no arguments are supplied.~%"))
     (else
      (format #t "[options]~%o(output): ON~%q(quiet): ~A~%d(debug): ~A~%~%"
              (if quiet 'ON 'OFF)
              debug)
      (format #t "[parameters]~%# of pamameters: ~A~%" (length rargv))
      (for-each-with-index (lambda (i x) (format #t "~A: ~A~%" (+ i 1) x))
                           (reverse rargv))
      (exit 0)))
    1))