bstring-no-properties (point)
                                                                        end-keyword))
                                  keywords))
                     ;; Disregard already marked strings.
                     (progn
                       (goto-char end)
                       (setq start nil
                             end nil)))))))
    ;; Return the found string, if any.
    (and start end
         (list (po-extract-unquoted (current-buffer) start end) start end))))

(defun po-mark-emacs-lisp-string (start end keyword)
  "Mark the Emacs LISP string, from START to END, with KEYWORD.
Leave point after marked string."
  (goto-char end)
  (insert ")")
  (save-excursion
    (goto-char start)
    (insert "(" keyword)
    (or (string-equal keyword "_") (insert " "))))