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Re: Unquoted special characters in regexps
From: |
Luc Teirlinck |
Subject: |
Re: Unquoted special characters in regexps |
Date: |
Fri, 3 Mar 2006 17:48:25 -0600 (CST) |
Martin Rudalics wrote:
The question whether writing '\\' before the `]' is relevant for the
example cited above. Usually, when I see a `\\]' outside a character
alternative I expect it to match a right bracket in some text. And,
usually, in that text a left bracket will precede the right bracket.
Hence, if in the text above the author had used `\\]' instead of `\]' it
would have been easy to conclude - from the absence of a preceding `\\['
- that something went wrong. Vice versa, when seeing a `\\[' I usually
expect it to have a corresponding `\\]' somehwere on the right.
I believe that you make understanding regexps hard on yourself by
making all kind of assumptions that often are not satisfied.
There is no reason why a literal `]' should be matched by a literal
`[' to the right or vice versa. Even _if_ the `[' and the `]' balance
in the text you are parsing through _considered in its entirety_
(which is not at all guaranteed), you might be inside, say, a nested
Lisp vector and your regexp may be searching for its end. No balance
of literal `[' and `]' at all. This is _not_ an exceptional
situation. It occurs all over the place in the Emacs source code.
Sincerely,
Luc.
- Re: Unquoted special characters in regexps, (continued)
- Re: Unquoted special characters in regexps, Luc Teirlinck, 2006/03/03
- Re: Unquoted special characters in regexps, Luc Teirlinck, 2006/03/03
- Re: Unquoted special characters in regexps, Luc Teirlinck, 2006/03/04
- Re: Unquoted special characters in regexps, Richard Stallman, 2006/03/04
- Re: Unquoted special characters in regexps, martin rudalics, 2006/03/03
- Re: Unquoted special characters in regexps, Richard Stallman, 2006/03/04
- Re: Unquoted special characters in regexps, martin rudalics, 2006/03/04
- Re: Unquoted special characters in regexps, Richard Stallman, 2006/03/05
- Re: Unquoted special characters in regexps, Richard Stallman, 2006/03/04
- Re: Unquoted special characters in regexps, martin rudalics, 2006/03/04
- Re: Unquoted special characters in regexps,
Luc Teirlinck <=
- Re: Unquoted special characters in regexps, martin rudalics, 2006/03/04
- Re: Unquoted special characters in regexps, Luc Teirlinck, 2006/03/04
- Re: Unquoted special characters in regexps, Luc Teirlinck, 2006/03/04
- Re: Unquoted special characters in regexps, Richard Stallman, 2006/03/05
- Re: Unquoted special characters in regexps, Luc Teirlinck, 2006/03/04
- Re: Unquoted special characters in regexps, martin rudalics, 2006/03/04
- Re: Unquoted special characters in regexps, Luc Teirlinck, 2006/03/04
- Re: Unquoted special characters in regexps, martin rudalics, 2006/03/01
- Re: Unquoted special characters in regexps, Andreas Schwab, 2006/03/02
- Re: Unquoted special characters in regexps, martin rudalics, 2006/03/01