Re: new Mail-Followup-To patch...please take a look...

[Per Abrahamsen <abraham@dina.kvl.dk>]

Josh Huber <huber@alum.wpi.edu> writes:

> This one incorporates (I think) all of the changes that people have
> mentioned.  Caching, defaulting to use the to-(address|list) unless a
> not-subscribed group parameter is present, automatically inserting
> this caching function into message-subscribed-address-functions on
> startup, etc.

I disagree with most of the changes. Caches tend to get out of sync
and add complexity, much better to make the primary access functions
fast. I have a included a version which I think is "fast enough" when
byte compiled.  I have committed gnus-group-fast-parameter to CVS.

I already argued against "non-subscribed", and Emacs Lisp code should
not modify user options.  I don't know how to do the later right, but
perhaps something like how message-post-method is implemented.

Here is a fast (when byte-compiled) version of
`gnus-find-subscribed-addresses':

(defun gnus-expand-group-parameter (match value group)
  "Use MATCH to expand VALUE in GROUP."
  (with-temp-buffer
    (insert group)
    (goto-char (point-min))
    (while (re-search-forward match nil t)
      (replace-match value))
    (buffer-string)))

(defun gnus-group-fast-parameter (group symbol &optional allow-list)
  "For GROUP, return the value of SYMBOL.

You should call this in the `gnus-group-buffer' buffer.  
The function `gnus-group-find-parameter' will do that for you."
  ;; The speed trick:  No cons'ing and quit early.
  (or (let ((params (funcall gnus-group-get-parameter-function group)))
	;; Start easy, check the "real" group parameters.
	(gnus-group-parameter-value params symbol allow-list))
      ;; We didn't found it there, try `gnus-parameters'.
      (let ((result nil)
	    (head nil)
	    (tail gnus-parameters))
	;; A good old-fashioned non-cl loop.
	(while tail
	  (setq head (car tail)
		tail (cdr tail))
	  ;; The car is regexp matching for matching the group name.
	  (when (string-match (car head) group)
	    ;; The cdr is the parameters.
	    (setq result (gnus-group-parameter-value (cdr head) 
						     symbol allow-list))
	    (when result
	      ;; Expand if necessary.
	      (if (and (stringp result) (string-match "\\\\" result))
		  (setq result (gnus-expand-group-parameter (car head)
							    result group)))
	      ;; Exit the loop early.
	      tail nil)))
	;; Done.
	result)))

(defun gnus-find-subscribed-addresses ()
  "Return a regexp matching the addresses of all subscribed mail groups.
It consists of the `to-address' or `to-list' parameter of all groups
with a nil `not-subscribed' parameter."
  (save-excursion
    (set-buffer gnus-group-buffer)
    (let ((addresses))
      (mapc (lambda (entry)
	      (let ((group (car entry)))
		(when (gnus-group-fast-parameter group 'subscribed)
		  (let ((address (or
				  (gnus-group-fast-parameter group 'to-address)
				  (gnus-group-fast-parameter group 'to-list))))
		    (when address
		      (setq addresses (cons address addresses)))))))
	    (cdr gnus-newsrc-alist))
      (mapconcat 'regexp-quote addresses "\\|"))))