Path: utzoo!utgpu!attcan!uunet!husc6!mit-eddie!esl.esl.COM!lrs
From: lrs@esl.esl.COM (Lynn Slater)
Newsgroups: comp.emacs
Subject: Filters in RMAIL
Message-ID: <8810211419.AA04402@esl.ESL.COM>
Date: 21 Oct 88 14:19:43 GMT
Sender: daemon@eddie.MIT.EDU
Lines: 61

Lloyd Zusman writes:
> So, I would like to filter my mail in a different manner.  Since I use
> rmail inside of GNU Emacs, it seems to me that it would be nice if the
> 'rmail-get-new-mail' function could optionally filter the messages as
> it takes them from my system mailbox and writes them into my RMAIL
> mailbox.  Some sort of hook could be used for this, I presume.

Why must the work be done in rmail-get-new-mail?  

It may be easier to write a function that scans the messages already
in the RMAIL file and removes/forwards certain ones of them.  This
would let you use the fill range or emacs functions such as range
constrained string search, point/line motion, etc.  The filter will
probably be easier to write and test.

You could then bind a key to a function that would first read the mail
and would then invoke the filter.

Try something like the following:

Warning: this is not tested code or code that I use.  I am posting
this because the problem described may be common and the ideas below
may help.  Do not use the below without checking it carefully first.

(defvar rmail-filters nil
  "A list of the filter function to call on each mail message")

(defun filter-rmail ()
  "Applies the rmail filters on all messages from here to end of mail"
  (interactive)
  (goto-char (point-min))
  (mapcar '(lambda (filter-fcn)  (save-excursion (apply filter-fcn nil)))
	  rmail-filters)
  (if (< rmail-current-message rmail-total-messages)
      (progn (rmail-next-message 1) (filter-rmail))))

;; now define some site specific filters. Demontrate 2 diff styles
(defun rmail-filter-VADS-messages ()
  "Does action X if the current message was a vads related message"
   (if (re-search-forward "\\(svug\\|vrdxhq\\|apso\\vads\\)"
			  (save-excursion (forward-line 5) (point)) t)
       (message "VADS message found")))

;; Add the filter to the filter hooks
(setq rmail-filters (cons 'rmail-filter-VADS-messages rmail-filters))

(defun rmail-filter-gnu-ada-messages ()
  "Does action X if the current message was a gnu-ada related message"
  (re-search-forward "Subject:.*$")
 (if (re-search-backward "gnu.*ada" (match-beginning 0) t)
      (message "Gnu Ada Message Found")))
			
;; Add the filter to the filter hooks
(setq rmail-filters (cons 'rmail-filter-gnu-ada-messages rmail-filters))

-- Lynn
===============================================================
Lynn Slater -- lrs@esl.com
ESL/TRW 495 Java Drive, Box 3510, Sunnyvale, Ca 94088-3510
Office (408) 738-2888 x 4482; Home (415) 796-4149 
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