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From: Katsumi Yamaoka <yamaoka@jpl.org>
Subject: Re: how to turn this Gnus function into a macro?
Date: Thu, 08 Jan 2004 11:13:52 +0900	[thread overview]
Message-ID: <b9yvfnn2nmn.fsf@jpl.org> (raw)
In-Reply-To: <4noetfo10c.fsf@collins.bwh.harvard.edu>

>>>>> In <4noetfo10c.fsf@collins.bwh.harvard.edu>
>>>>>	Ted Zlatanov <tzz@lifelogs.com> wrote:

> I tried to make this function into a macro but failed.

How about it?

(defmacro spam-fetch-field-fast (article field)
  "Fetch a field quickly, using the internal gnus-data-list function"
  (let ((macro (cond ((eq field 'from) 'mail-header-from)
		     ((eq field 'message-id) 'mail-header-message-id)
		     ((eq field 'subject) 'mail-header-subject)
		     ((eq field 'references) 'mail-header-references)
		     ((eq field 'date) 'mail-header-date)
		     ((eq field 'xref) 'mail-header-xref)
		     ((eq field 'extra) 'mail-header-extra))))
    (if macro
	`(let ((article ,article))
	   (if (numberp article)
	       (let* ((header (assoc article (gnus-data-list nil)))
		      (data-header (if header (gnus-data-header header))))
		 (,macro data-header)))))))

(macroexpand '(spam-fetch-field-fast ART from))
 => (let ((article ART))
      (if (numberp article)
	  (let* ((header (assoc article (gnus-data-list nil)))
		 (data-header (if header (gnus-data-header header))))
	    (mail-header-from data-header))))

If the arg `article' is always not a cons form (i.e., a number
or a symbol), it can be simplified as follows:

(defmacro spam-fetch-field-fast (article field)
  "Fetch a field quickly, using the internal gnus-data-list function"
  (let ((macro (cond ((eq field 'from) 'mail-header-from)
		     ((eq field 'message-id) 'mail-header-message-id)
		     ((eq field 'subject) 'mail-header-subject)
		     ((eq field 'references) 'mail-header-references)
		     ((eq field 'date) 'mail-header-date)
		     ((eq field 'xref) 'mail-header-xref)
		     ((eq field 'extra) 'mail-header-extra))))
    (if macro
	`(if (numberp ,article)
	     (let* ((header (assoc ,article (gnus-data-list nil)))
		    (data-header (if header (gnus-data-header header))))
	       (,macro data-header))))))

(macroexpand '(spam-fetch-field-fast ART from))
 => (if (numberp ART)
	(let* ((header (assoc ART (gnus-data-list nil)))
	       (data-header (if header (gnus-data-header header))))
	  (mail-header-from data-header)))
-- 
Katsumi Yamaoka <yamaoka@jpl.org>



  parent reply	other threads:[~2004-01-08  2:13 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-01-07 22:19 Ted Zlatanov
2004-01-07 22:55 ` Jesper Harder
2004-01-08  0:09   ` Ted Zlatanov
2004-01-08  4:13     ` Jesper Harder
2004-01-08  2:13 ` Katsumi Yamaoka [this message]
2004-01-08  3:28   ` Ted Zlatanov
2004-01-08  3:33     ` Katsumi Yamaoka
2004-01-08  3:42     ` Jeremy Maitin-Shepard
2004-01-08  3:47       ` Katsumi Yamaoka
2004-01-08  4:06         ` Jeremy Maitin-Shepard
2004-01-08  6:06         ` Katsumi Yamaoka
2004-01-08 20:30           ` Ted Zlatanov

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