Gnus MIME charset advice, with XEmacs

[Aidan Kehoe <kehoea@parhasard.net>]

Hi!

I'm not in East Asia, yet I occasionally use Gnus to post messages to Usenet
which venture beyond ISO-8859-1, or, even, ISO-8859-15. The below advice
makes this possible, preferring UTF-8 to the XEmacs default of ISO-2022-JP
and/or multipart encodings. (Nothing but Emacs understands postings that
have been multipart-encoded for different character sets, to my knowledge.)

It's not that full-featured, and should be written to take advantage of
Stephen Turnbull's Latin Unity, and to take notice of
mm-coding-system-priorities. But it does what I want for the moment, and I
think it may be useful for other people wanting to do similar things. 

If you're using the stable version of XEmacs, you'll need to load Mule-UCS
to have Gnus find the UTF-8 coding system. I have; 

  (unless (or (coding-system-p (find-coding-system 'utf-8))
	      (null (locate-library "un-define")))
    (require 'un-define)
    (require 'unidata))

in my ~/.xemacs/init.el, which has the nice side affect of also working on,
and not interfering with, 21.5 and its built-in Unicode support. 

Bye, 
        - Aidan

;; Try to get GNUS to do the sane thing when sending messages that can't be
;; encoded in Latin 1.
(defadvice mm-find-mime-charset-region (after do-sane-mime-charset-select
					       activate)
  "Look at the contents of a message, and if they fit in ASCII, return nil.
If they fit in ISO-8859-1, return `iso-8859-1', otherwise return `utf-8'. 

Should revise this to use Latin Unity, and a configurable list of preferred
MIME character sets. "
  (let ((charsets (delq 'ascii (charsets-in-region (ad-get-arg 0)
						    (ad-get-arg 1)))))
    (setq ad-return-value (cond 
			   ((null charsets) nil) 
			   ((and (eq 1 (length charsets)) 
				 (eq 'latin-iso8859-1 (car charsets)))
			    '(iso-8859-1))
			   (t '(utf-8))))))

-- 
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