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From: Xah Lee <xahlee@gmail.com>
To: help-gnu-emacs@gnu.org
Subject: elisp 23.2 doc on regex on multibyte char still correct?
Date: Mon, 3 Jan 2011 01:12:47 -0800 (PST)	[thread overview]
Message-ID: <bfe04f3a-8f03-4c9f-9d66-758667f76239@c17g2000prm.googlegroups.com> (raw)


in elisp doc for emacs 23.2, section on regex, it
it has a section that talks about multibyte chars.

is that info still correct?

________________________________________


This is edition 3.0 of the GNU Emacs Lisp Reference Manual,
corresponding to Emacs version 23.2.

(elisp) Regexp Special

     The beginning and end of a range of multibyte characters must be
in
     the same character set (*note Character Sets::).  Thus,
     `"[\x8e0-\x97c]"' is invalid because character 0x8e0 (`a' with
     grave accent) is in the Emacs character set for Latin-1 but the
     character 0x97c (`u' with diaeresis) is in the Emacs character
set
     for Latin-2.  (We use Lisp string syntax to write that example,
     and a few others in the next few paragraphs, in order to include
     hex escape sequences in them.)

     If a range starts with a unibyte character C and ends with a
     multibyte character C2, the range is divided into two parts: one
     is `C..?\377', the other is `C1..C2', where C1 is the first
     character of the charset to which C2 belongs.

     You cannot always match all non-ASCII characters with the regular
     expression `"[\200-\377]"'.  This works when searching a unibyte
     buffer or string (*note Text Representations::), but not in a
     multibyte buffer or string, because many non-ASCII characters
have
     codes above octal 0377.  However, the regular expression
     `"[^\000-\177]"' does match all non-ASCII characters (see below
     regarding `^'), in both multibyte and unibyte representations,
     because only the ASCII characters are excluded.

     A character alternative can also specify named character classes
     (*note Char Classes::).  This is a POSIX feature whose syntax is
     `[:CLASS:]'.  Using a character class is equivalent to mentioning
     each of the characters in that class; but the latter is not
     feasible in practice, since some classes include thousands of
     different characters.

________________________________________

 Xah ∑ http://xahlee.org/

             reply	other threads:[~2011-01-03  9:12 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-01-03  9:12 Xah Lee [this message]
2011-01-03 18:17 ` elisp 23.2 doc on regex on multibyte char still correct? Eli Zaretskii
     [not found] ` <mailman.7.1294078730.3992.help-gnu-emacs@gnu.org>
2011-01-03 21:25   ` Xah Lee

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