diff --git a/misc/ruby-additional.el b/misc/ruby-additional.el
index e3f6a02f4d..2aa20cba38 100644
--- a/misc/ruby-additional.el
+++ b/misc/ruby-additional.el
@@ -114,11 +114,23 @@ Emacs to Ruby."
        (setq end (set-marker (make-marker) end))
        (goto-char beg)
        (while (and (< (point) end)
-		   (re-search-forward "[^\C-@-~]+" end t))
-	 (let ((u (mapconcat (lambda (c) (format "%x" c)) (match-string-no-properties 0) " ")))
+		   (re-search-forward "\\([\C-@-\C-I\C-K\C-_\C-?]+\\)\\|[^\C-@-\C-?]+" end t))
+	 (let ((str (match-string-no-properties 0)) sep b e f)
+	   (if (match-beginning 1)
+	       (setq b "" e "" sep ""
+		     f (lambda (c)
+			 (cond ((= c ?\t) "\\t")
+			       ((= c ?\r) "\\r")
+			       ((= c ?\e) "\\e")
+			       ((= c ?\f) "\\f")
+			       ((= c ?\b) "\\b")
+			       ((= c ?\v) "\\v")
+			       ((= c ?\C-?) "\\c?")
+			       ((concat "\\c" (char-to-string (logior c #x40)))))))
+	     (setq b "\\u{" e "}" sep " " f (lambda (c) (format "%x" c))))
+	   (setq str (mapconcat f str sep))
 	   (delete-region (match-beginning 0) (match-end 0))
-	   (insert "\\u{" u "}"))
-	 ))
+	   (insert b str e))))
      ))
 
 ;; monkey-patching ruby-mode.el in Emacs 24, as r49872.