From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: tomas@tuxteam.de Newsgroups: gmane.emacs.help Subject: Re: Determining existence of text following point Date: Tue, 18 May 2021 14:35:42 +0200 Message-ID: <20210518123541.GF11623@tuxteam.de> References: <87zgwsx5r3.fsf@ericabrahamsen.net> <20210518110743.GC11623@tuxteam.de> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="TeJTyD9hb8KJN2Jy" Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="12990"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Mutt/1.5.21 (2010-09-15) Cc: help-gnu-emacs@gnu.org, Jean Louis To: Christopher Dimech Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Tue May 18 14:38:10 2021 Return-path: Envelope-to: geh-help-gnu-emacs@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1liyzB-0003DB-HM for geh-help-gnu-emacs@m.gmane-mx.org; Tue, 18 May 2021 14:38:09 +0200 Original-Received: from localhost ([::1]:55628 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1liyzA-0000Ea-6S for geh-help-gnu-emacs@m.gmane-mx.org; Tue, 18 May 2021 08:38:08 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:49352) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1liywt-0006yn-EG for help-gnu-emacs@gnu.org; Tue, 18 May 2021 08:35:49 -0400 Original-Received: from mail.tuxteam.de ([5.199.139.25]:60334) by eggs.gnu.org with esmtps (TLS1.2:DHE_RSA_AES_128_CBC_SHA1:128) (Exim 4.90_1) (envelope-from ) id 1liywq-0001i5-Dd for help-gnu-emacs@gnu.org; Tue, 18 May 2021 08:35:47 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=tuxteam.de; s=mail; h=In-Reply-To:Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date; bh=vz06PY8NVqvyCjjoNL+k/NtnTFIiR8kc1c7e4F5nTF8=; b=ZZAbTp73fYv3JeMWaOUMsZZ9rSekWjE5NxPw9QbGzknPDMz7X/3kGhWg4FeGoJzlDQs5QnpG8/McEkr93xL9Vw6MFywDs2EkXU9FmWi+mywn9QkpkYjDDef915lmW+f7e4ew3n71qYDD8H+rguDpGHN3jkh+uinDAmfawtebw9G4lNIDhHJ0xmzgxBtxBNAYk5gPlkW0Q4utrgbH24KJNW9SUAjQbYFbtp7gL1cVW0ge2tGRThc1Xk8L9+lR3DHFmSEkKOvxycdQXC9vvJVhDe0MlTc0NKgygNc7s3JrSsp4cYkBRo8yg9JT7A6rNKbmxXcB6wdPTbnRW4M/T0o71g==; Original-Received: from tomas by mail.tuxteam.de with local (Exim 4.80) (envelope-from ) id 1liywo-00075H-1T; Tue, 18 May 2021 14:35:42 +0200 Content-Disposition: inline In-Reply-To: Received-SPF: pass client-ip=5.199.139.25; envelope-from=tomas@tuxteam.de; helo=mail.tuxteam.de X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Original-Sender: "help-gnu-emacs" Xref: news.gmane.io gmane.emacs.help:129878 Archived-At: --TeJTyD9hb8KJN2Jy Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, May 18, 2021 at 02:23:25PM +0200, Christopher Dimech wrote: > > Sent: Tuesday, May 18, 2021 at 11:56 PM > > From: "Jean Louis" > > To: "Christopher Dimech" > > Cc: tomas@tuxteam.de, help-gnu-emacs@gnu.org > > Subject: Re: Determining existence of text following point > > > > * Christopher Dimech [2021-05-18 14:27]: > > > > > (setq sa (string-match "[^[:blank:]]" " ")) > >=20 > > > I find the description different from what string-match actually > > > returns. > >=20 > > The symbol ^ means "not following", and that regular expression means > > match non-blanks. > >=20 > > (string-match "[^[:blank:]]" " ") =E2=87=92 nil > > (string-match "[[:blank:]]" " ") =E2=87=92 0 >=20 > You are correct. "^" means match everything but the following class. >=20 > I am quite used on see "^" to mean "beginning of line". So just read > it as I usually do. This is outside the context of character classes, i.e. outside [...]. > It is unfortunate that there exist so many different syntaxes for writing > regular expressions. Yet all those syntaxes coincide in that one thing: "^" outside of brackets means "anchor at the beginning" (of line, most of the time, but it could be "of string" or similar), whereas inside of character class brackets (but _only_ right after the opening bracket!) it means complement. This is an unfortunate quirk, but those notations are around since the early 1970s, so that ship has sailed. Go and tell a phisicist to use something else than the "uppercase L" for the Lagrangian. The multitude of regular expression extensions and implementations is an issue, yes, but a completely different one. Cheers - t --TeJTyD9hb8KJN2Jy Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iEYEARECAAYFAmCjtJ0ACgkQBcgs9XrR2kZeOACfQzFTFUqMW4k64Tqwezuoiv98 XtAAn1+dzCW6S8d4RzRzV+oZ91tYlIVG =dwRm -----END PGP SIGNATURE----- --TeJTyD9hb8KJN2Jy--