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Re: Unquoted special characters in regexps
From: |
Richard Stallman |
Subject: |
Re: Unquoted special characters in regexps |
Date: |
Wed, 01 Mar 2006 12:54:49 -0500 |
`]', like `-' are only special in the context of a character
alternative, that is if, before you type them, you are in a character
alternative. By contrast, `[' and all other special characters
(except `^') are only special outside that context.
You're interpreting the term "context" the same way the regexp
compiler does: meaning the preceding characters of the regexp. The
regexp compiler works from left to right. However, to a person, the
context of a character set, or any sub-regexp, is found on both sides
of it. Understood in this way, the role of a character set's closing
] is dual to that of the opening [; both of them delimit the character
set. Both characters play special roles in the syntax of regexps, and
these roles are not internal to a character set.
First of all, there are (surprisingly) many occurrences of "\\]" in
the Emacs source, where the `]' _is_ special and closes a character
alternative that contains a slash.
That is a good point. We don't want people to get confused about that.
So I think we should not encourage the quoting of ], but we need to be
careful about how to explain this. I will write it.
Meanwhile, please do install your search.c patch.
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Re: Unquoted special characters in regexps, martin rudalics, 2006/03/02
Re: Unquoted special characters in regexps, Luc Teirlinck, 2006/03/02
Re: Unquoted special characters in regexps, martin rudalics, 2006/03/03
Re: Unquoted special characters in regexps, Luc Teirlinck, 2006/03/03
Re: Unquoted special characters in regexps, martin rudalics, 2006/03/03
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