From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Michael Heerdegen Newsgroups: gmane.emacs.help Subject: Re: How to get a concatenation of the negations with rx (ex: [^a][^b])? Date: Sun, 12 Nov 2023 08:03:18 +0100 Message-ID: <87leb3o3m1.fsf@web.de> References: <1417367556.377258.1699733869853@fidget.co-bxl> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="29715"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) To: help-gnu-emacs@gnu.org Cancel-Lock: sha1:QUADGV7vzo2kYhQXE3EMaEwDz+Q= Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Sun Nov 12 08:04:10 2023 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 1r24Vt-0007XQ-T7 for geh-help-gnu-emacs@m.gmane-mx.org; Sun, 12 Nov 2023 08:04:09 +0100 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1r24V7-0007zb-So; Sun, 12 Nov 2023 02:03:21 -0500 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1r24V5-0007zO-GQ for help-gnu-emacs@gnu.org; Sun, 12 Nov 2023 02:03:19 -0500 Original-Received: from ciao.gmane.io ([116.202.254.214]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1r24V3-0007Pr-J2 for help-gnu-emacs@gnu.org; Sun, 12 Nov 2023 02:03:18 -0500 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1r24V0-0006Gf-SX for help-gnu-emacs@gnu.org; Sun, 12 Nov 2023 08:03:15 +0100 X-Injected-Via-Gmane: http://gmane.org/ Received-SPF: pass client-ip=116.202.254.214; envelope-from=geh-help-gnu-emacs@m.gmane-mx.org; helo=ciao.gmane.io X-Spam_score_int: -13 X-Spam_score: -1.4 X-Spam_bar: - X-Spam_report: (-1.4 / 5.0 requ) BAYES_00=-1.9, FREEMAIL_FORGED_FROMDOMAIN=0.249, FREEMAIL_FROM=0.001, HEADER_FROM_DIFFERENT_DOMAINS=0.249, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.29 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-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.help:145482 Archived-At: Edgar Lux writes: > Hello. I am trying to get this regular expression: > > "[^a][^b]" > > in an easier way. I thought that I could do > > (rx (not (seq "a" "b"))) No, > but that got me > > Debugger entered--Lisp error: (error "Illegal argument to rx > ‘not’: (seq \"a\" \"b\")") this would also express something different: `not' is not distributive over `seq' concatenation of regexps -- a string starting with a character different from 'a' followed by a character different from 'b' is something different than a string not starting with "ab". > The error is very clear, I think `match a string not starting with "ab"' is not even expressible using a standalone standard regexp. That would require regexps to be able to backtrack when matching, and it would be something more general than regexps. > but I would like to know if there is a smart way of achieving the same > without having to type: > > (rx (seq (not "a") (not "b"))) Unless you actually wanted to express something different: the `seq' wrapper is redundant, but with (rx (not "a") (not "b")) a local maximum of smartness is reached. Michael.