
(define-key dired-mode-map "=" 'd-diff)

(defun d-diff ()
  (interactive)

  (let (list old new)
    (assert (eq major-mode 'dired-mode))
    (setq list (dired-get-marked-files))
    (assert (= 2 (length list)))

    (setq old (car list))
    (setq new (cadr list))
    (diff old new)))

(provide 'd-diff)
;;; d-diff.el ends here
