And something like

(defun rs-is-mid (mid-or-mail)
  (string-match
   "-> m-id$"
   (with-temp-buffer
     (insert (concat "<" mid-or-mail ">"))
     (call-process-region (point-min) (point-max)
			  shell-file-name t (list (current-buffer) nil)
			  nil shell-command-switch
			  "/home/rscholz/bin/id-or-mail.pl")
     (buffer-string))))

(setq gnus-button-prefer-mid-or-mail 'is-mid)


I'm not sure whether funcall should be protected with something like
`save-window-excursion'.

Cheers, Ray
-- 
http://www.zonix.de/ - (c) 2000 by Yamtaijika Corp.