From: David Kastrup <dak@gnu.org>
To: D. Goel <deego@gnufans.org>
Cc: Dave Goel <deego3@gmail.com>, emacs-devel@gnu.org
Subject: Re: Fixing numerous `message' bugs..
Date: Thu, 06 Dec 2007 11:56:25 +0100 [thread overview]
Message-ID: <85sl2gqeg6.fsf@lola.goethe.zz> (raw)
In-Reply-To: <87myso8yrs.fsf@marie.gnufans.net> (D. Goel's message of "Wed, 05 Dec 2007 19:14:47 -0500")
D. Goel <deego@gnufans.org> writes:
> The emacs source code is littered with thousands of buggy calls to
> `message'. Here is an example of such a structure:
>
>
> (message
> (if foo
> nil
> (if bar "abc"
> (concat "def" filename))))
>
> This example will lead to an error if the filename has %s in it.
>
> At the same time, the simplistic fix of replacing (message by (message
> "%s" would be incorrect because if foo is true, the coder wanted
> (message nil), and not (message "%s" nil).
>
>
> The appropriate fix to this would be
>
> (let ((arg ((rest-of-the-code))))
> (if (null arg)
> (message nil)
> (message "%s" arg)))
(message (unless foo (if bar "abc" "def%s")) filename)
Note that it is perfectly fine to have spurious trailing arguments to
message.
>
> ^^^ This fix will have to be repeated thousands of time as I go
> through the source code.
>
> It would rather make much more sense to code this fix into a little
> function:
>
> (defun msg (arg)
> (if (null arg)
> (message nil)
> (message (format "%s" arg))))
^^^^^^^^^^^^^^^^^^^^^^^^^^^
Uh, no. You mean (message "%s" arg) here, and anyway:
(defun msg (arg)
(message (and arg "%s") arg))
and then it is simple enough that it is not worth bothering introducing
a separate function. Of course, arg should not involve a complex
calculation.
> .. this new function can be further improved to be more general, so
> that develepors can simply start preferring the new msg if they like -
>
> (defun msg (&rest args)
> (cond
> ((null args) (message nil))
> ((null (car args) (message nil)))
> ((= (length args) 1) (message "%s" (car args)))
> (apply 'message args)))
I think that is nonsensical. Problems occur only when a message
contains non-fixed material (which may or may not contain percentages),
but a message will pretty much never contain _exclusively_ non-fixed
material. So a good solution will almost always involve more than a
trivial "%s" format.
--
David Kastrup, Kriemhildstr. 15, 44793 Bochum
next prev parent reply other threads:[~2007-12-06 10:56 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-12-06 0:14 Fixing numerous `message' bugs D. Goel
2007-12-06 10:56 ` David Kastrup [this message]
2007-12-06 14:36 ` Dave Goel
2007-12-06 19:26 ` Glenn Morris
2007-12-06 19:34 ` Dave Goel
2007-12-06 20:21 ` Johan Bockgård
2007-12-07 5:28 ` Glenn Morris
2007-12-07 15:52 ` Dave Goel
2007-12-06 15:53 ` Stefan Monnier
2007-12-06 16:01 ` Dave Goel
2007-12-06 16:49 ` Stefan Monnier
2007-12-06 16:58 ` David Kastrup
2007-12-06 17:19 ` David Kastrup
2007-12-07 17:17 ` Richard Stallman
2007-12-07 17:37 ` David Kastrup
2007-12-07 17:17 ` Richard Stallman
2007-12-07 17:18 ` Richard Stallman
2007-12-07 17:24 ` David Kastrup
2007-12-07 18:00 ` Dave Goel
2007-12-07 18:38 ` Stefan Monnier
2007-12-08 0:56 ` Glenn Morris
2007-12-08 2:21 ` Stefan Monnier
2007-12-08 10:55 ` David Kastrup
2007-12-08 19:15 ` Richard Stallman
2007-12-10 17:41 ` Dave Goel
2007-12-10 18:04 ` Jason Rumney
2007-12-10 19:05 ` Dave Goel
2007-12-10 19:56 ` Andreas Schwab
2007-12-10 20:31 ` Dave Goel
2007-12-10 21:19 ` David Kastrup
2007-12-10 22:44 ` Dave Goel
2007-12-10 23:02 ` David Kastrup
2007-12-08 19:15 ` Richard Stallman
2007-12-07 17:18 ` Richard Stallman
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