From mboxrd@z Thu Jan  1 00:00:00 1970
Path: news.gmane.org!.POSTED!not-for-mail
From: Eric Abrahamsen <eric@ericabrahamsen.net>
Newsgroups: gmane.emacs.help
Subject: Difference between \\w and [:word:]?
Date: Thu, 07 Jun 2018 12:18:53 -0700
Message-ID: <87y3fqquaq.fsf@ericabrahamsen.net>
NNTP-Posting-Host: blaine.gmane.org
Mime-Version: 1.0
Content-Type: text/plain
X-Trace: blaine.gmane.org 1528399070 24728 195.159.176.226 (7 Jun 2018 19:17:50 GMT)
X-Complaints-To: usenet@blaine.gmane.org
NNTP-Posting-Date: Thu, 7 Jun 2018 19:17:50 +0000 (UTC)
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.0.50 (gnu/linux)
To: help-gnu-emacs@gnu.org
Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Thu Jun 07 21:17:46 2018
Return-path: <help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org>
Envelope-to: geh-help-gnu-emacs@m.gmane.org
Original-Received: from lists.gnu.org ([208.118.235.17])
	by blaine.gmane.org with esmtp (Exim 4.84_2)
	(envelope-from <help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org>)
	id 1fR0Pp-0006J2-Ct
	for geh-help-gnu-emacs@m.gmane.org; Thu, 07 Jun 2018 21:17:45 +0200
Original-Received: from localhost ([::1]:59848 helo=lists.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org>)
	id 1fR0Rw-0003bY-ED
	for geh-help-gnu-emacs@m.gmane.org; Thu, 07 Jun 2018 15:19:56 -0400
Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:60755)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <geh-help-gnu-emacs@m.gmane.org>) id 1fR0RA-0003ZQ-BB
	for help-gnu-emacs@gnu.org; Thu, 07 Jun 2018 15:19:09 -0400
Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <geh-help-gnu-emacs@m.gmane.org>) id 1fR0R5-0007Lp-Ax
	for help-gnu-emacs@gnu.org; Thu, 07 Jun 2018 15:19:08 -0400
Original-Received: from [195.159.176.226] (port=44962 helo=blaine.gmane.org)
	by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16)
	(Exim 4.71) (envelope-from <geh-help-gnu-emacs@m.gmane.org>)
	id 1fR0R5-0007H1-33
	for help-gnu-emacs@gnu.org; Thu, 07 Jun 2018 15:19:03 -0400
Original-Received: from list by blaine.gmane.org with local (Exim 4.84_2)
	(envelope-from <geh-help-gnu-emacs@m.gmane.org>) id 1fR0Ot-0005Em-Vn
	for help-gnu-emacs@gnu.org; Thu, 07 Jun 2018 21:16:47 +0200
X-Injected-Via-Gmane: http://gmane.org/
Original-Lines: 8
Original-X-Complaints-To: usenet@blaine.gmane.org
Cancel-Lock: sha1:Sz4ukQryLygVESRoR2NG4hV3l1w=
X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic]
	[fuzzy]
X-Received-From: 195.159.176.226
X-BeenThere: help-gnu-emacs@gnu.org
X-Mailman-Version: 2.1.21
Precedence: list
List-Id: Users list for the GNU Emacs text editor <help-gnu-emacs.gnu.org>
List-Unsubscribe: <https://lists.gnu.org/mailman/options/help-gnu-emacs>,
	<mailto:help-gnu-emacs-request@gnu.org?subject=unsubscribe>
List-Archive: <http://lists.gnu.org/archive/html/help-gnu-emacs/>
List-Post: <mailto:help-gnu-emacs@gnu.org>
List-Help: <mailto:help-gnu-emacs-request@gnu.org?subject=help>
List-Subscribe: <https://lists.gnu.org/mailman/listinfo/help-gnu-emacs>,
	<mailto:help-gnu-emacs-request@gnu.org?subject=subscribe>
Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org
Original-Sender: "help-gnu-emacs"
	<help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org>
Xref: news.gmane.org gmane.emacs.help:117024
Archived-At: <http://permalink.gmane.org/gmane.emacs.help/117024>

Can someone explain to me what's happening here? What's the difference
between \\w and [:word:], inside and outside of a bracket construction?

(setq case-fold-search nil)
(string-match-p "[:word:]" "P") => nil
(string-match-p "[[:word:]]" "P") => 0
(string-match-p "\\w" "P") => 0
(string-match-p "[\\w]" "P") = nil