From: martin rudalics <rudalics@gmx.at>
Cc: Luc Teirlinck <teirllm@dms.auburn.edu>, emacs-devel@gnu.org
Subject: Re: Unquoted special characters in regexps
Date: Sun, 26 Feb 2006 18:10:10 +0100 [thread overview]
Message-ID: <4401E0F2.7030800@gmx.at> (raw)
In-Reply-To: <jefym6ut3l.fsf@sykes.suse.de>
>>That of closing a character alternative. When you write
>>
>>(defvar foo "]")
>>(defvar bar "\\]")
>>
>>you can't interchangeably use `foo' and `bar' in an arbitrary regular
>>expression. Some people call this "referential transparency".
>
>
> Of course you can't, since the meaning of '\' is context dependent.
When you say that outside a character alternative `]' and `\\]' have the
same meaning you abandon the principle of referential transparency.
>>Anyway, the first `]' has a special meaning but it's not "inside" the
>>character alternative.
>
>
> It is part of it, just like the leading '['.
As a consequence, in your model "[" is a valid regexp too.
>>It does have a special meaning because `]' is special _outside_
>>character alternatives.
>
>
> This is wrong. Outside of a character set ']' has no special meaning
> whatsoever, independent of the context.
On a similar footing you can say that `*' has no special meaning unless
it's preceded by a character. Hence "*foo" is valid too in your model.
>>According to the Elisp manual all these exhibit "poor practice" since
>>you didn't quote the second `]'s.
>
>
> It's a bug in the manual.
Please fix it.
next prev parent reply other threads:[~2006-02-26 17:10 UTC|newest]
Thread overview: 81+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-02-25 17:23 Unquoted special characters in regexps martin rudalics
2006-02-25 18:42 ` Andreas Schwab
2006-02-25 19:18 ` martin rudalics
2006-02-25 19:31 ` Andreas Schwab
2006-02-25 20:18 ` martin rudalics
2006-02-25 22:09 ` Andreas Schwab
2006-02-26 11:32 ` martin rudalics
2006-02-26 11:50 ` Andreas Schwab
2006-02-26 13:28 ` martin rudalics
2006-02-25 22:13 ` Luc Teirlinck
2006-02-26 13:13 ` martin rudalics
2006-02-26 13:50 ` Andreas Schwab
2006-02-26 16:41 ` Luc Teirlinck
2006-02-26 17:53 ` martin rudalics
2006-02-26 18:22 ` Luc Teirlinck
2006-02-26 19:26 ` martin rudalics
2006-02-26 17:10 ` martin rudalics [this message]
2006-02-26 17:42 ` Luc Teirlinck
2006-02-26 19:06 ` martin rudalics
2006-02-26 17:56 ` Andreas Schwab
2006-02-26 19:08 ` martin rudalics
2006-02-27 19:03 ` Richard Stallman
2006-02-27 19:36 ` Andreas Schwab
2006-02-27 20:03 ` martin rudalics
2006-02-27 20:32 ` Andreas Schwab
2006-02-27 21:43 ` martin rudalics
2006-02-27 22:11 ` Andreas Schwab
2006-02-28 6:19 ` Richard Stallman
2006-02-28 10:28 ` martin rudalics
2006-02-28 0:30 ` Luc Teirlinck
2006-02-28 10:27 ` martin rudalics
2006-02-28 22:57 ` Luc Teirlinck
2006-03-01 13:00 ` martin rudalics
2006-03-01 17:54 ` Richard Stallman
2006-03-02 4:06 ` Luc Teirlinck
2006-03-02 19:43 ` Richard Stallman
2006-03-02 4:54 ` Luc Teirlinck
2006-03-02 18:40 ` martin rudalics
2006-03-02 23:26 ` Luc Teirlinck
2006-03-03 7:42 ` martin rudalics
2006-03-03 13:51 ` Luc Teirlinck
2006-03-03 14:09 ` Luc Teirlinck
2006-03-03 18:52 ` martin rudalics
2006-03-03 22:41 ` Luc Teirlinck
2006-03-03 23:00 ` Luc Teirlinck
2006-03-03 10:25 ` Richard Stallman
2006-03-03 15:20 ` martin rudalics
2006-03-04 13:37 ` Richard Stallman
2006-03-04 14:40 ` martin rudalics
2006-03-06 0:48 ` Richard Stallman
2006-03-03 10:25 ` Richard Stallman
2006-03-03 15:51 ` martin rudalics
2006-03-03 23:48 ` Luc Teirlinck
2006-03-04 9:58 ` martin rudalics
2006-03-04 23:16 ` Luc Teirlinck
2006-03-05 2:54 ` Luc Teirlinck
2006-03-06 0:49 ` Richard Stallman
2006-02-28 0:44 ` Luc Teirlinck
2006-03-04 21:07 ` Thien-Thi Nguyen
2006-03-05 3:37 ` Luc Teirlinck
2006-03-05 11:10 ` martin rudalics
2006-03-05 15:32 ` Luc Teirlinck
2006-03-06 7:41 ` martin rudalics
2006-03-05 17:04 ` Luc Teirlinck
2006-03-05 11:54 ` martin rudalics
2006-03-05 15:35 ` Andreas Schwab
2006-03-06 8:19 ` martin rudalics
2006-03-05 18:36 ` Luc Teirlinck
2006-03-05 19:14 ` Luc Teirlinck
2006-03-06 8:17 ` martin rudalics
2006-02-28 0:59 ` Luc Teirlinck
2006-03-06 12:52 ` Richard Stallman
2006-03-07 5:52 ` Luc Teirlinck
2006-03-07 8:53 ` martin rudalics
2006-02-25 22:34 ` Luc Teirlinck
2006-02-25 22:59 ` Andreas Schwab
2006-02-26 13:20 ` martin rudalics
2006-02-26 16:53 ` Luc Teirlinck
2006-02-26 18:01 ` martin rudalics
2006-02-26 17:19 ` Luc Teirlinck
2006-02-26 18:13 ` martin rudalics
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