From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED.blaine.gmane.org!not-for-mail From: Alan Mackenzie Newsgroups: gmane.emacs.devel Subject: Re: regular expressions that match nothing Date: Wed, 15 May 2019 19:41:29 +0000 Message-ID: <20190515194129.GA4103@ACM> References: <7a6b23f52418b093a4cf7a6db4306cf425533249.camel@acm.org> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Injection-Info: blaine.gmane.org; posting-host="blaine.gmane.org:195.159.176.226"; logging-data="126219"; mail-complaints-to="usenet@blaine.gmane.org" User-Agent: Mutt/1.10.1 (2018-07-13) Cc: Stefan Monnier , emacs-devel@gnu.org To: Mattias =?iso-8859-1?Q?Engdeg=E5rd?= Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Wed May 15 21:41:46 2019 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([209.51.188.17]) by blaine.gmane.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:256) (Exim 4.89) (envelope-from ) id 1hQzma-000Wi1-DE for ged-emacs-devel@m.gmane.org; Wed, 15 May 2019 21:41:44 +0200 Original-Received: from localhost ([127.0.0.1]:41579 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hQzmZ-0007Yp-70 for ged-emacs-devel@m.gmane.org; Wed, 15 May 2019 15:41:43 -0400 Original-Received: from eggs.gnu.org ([209.51.188.92]:39895) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hQzmT-0007Yf-3p for emacs-devel@gnu.org; Wed, 15 May 2019 15:41:38 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hQzmS-0007aN-51 for emacs-devel@gnu.org; Wed, 15 May 2019 15:41:37 -0400 Original-Received: from colin.muc.de ([193.149.48.1]:31384 helo=mail.muc.de) by eggs.gnu.org with smtp (Exim 4.71) (envelope-from ) id 1hQzmR-0007Ya-R9 for emacs-devel@gnu.org; Wed, 15 May 2019 15:41:36 -0400 Original-Received: (qmail 25084 invoked by uid 3782); 15 May 2019 19:41:31 -0000 Original-Received: from acm.muc.de (p4FE15DB3.dip0.t-ipconnect.de [79.225.93.179]) by colin.muc.de (tmda-ofmipd) with ESMTP; Wed, 15 May 2019 21:41:29 +0200 Original-Received: (qmail 4108 invoked by uid 1000); 15 May 2019 19:41:29 -0000 Content-Disposition: inline In-Reply-To: <7a6b23f52418b093a4cf7a6db4306cf425533249.camel@acm.org> X-Delivery-Agent: TMDA/1.1.12 (Macallan) X-Primary-Address: acm@muc.de X-detected-operating-system: by eggs.gnu.org: FreeBSD 9.x [fuzzy] X-Received-From: 193.149.48.1 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.org gmane.emacs.devel:236549 Archived-At: Hello, Mattias. On Wed, May 15, 2019 at 18:21:07 +0200, Mattias Engdegård wrote: > tis 2019-05-14 klockan 15:41 -0400 skrev Stefan Monnier: > > Yes, please. I'd recommend a `regexp-` prefix for it. > Well, since you asked so nicely! > > [ And I'll carefully avoid having an opinion on the rest of the name. > > ] > The correct name is obviously something like `regexp-empty', but I have > to concede that it might be misinterpreted. The attached patch uses > `regexp-unmatchable' which is reasonably descriptive. Better > suggestions are welcome. I think regexp-unmatchable is too much of a mouthful. It is more difficult to type that a\\` (or whatever), even after having to think where the seldom used keys are on the keyboard. Also it is difficult to spell. is it unmatchable or unmatcheable? I would suggest re-nomatch (or possibly nomatch-re), which is just 10 characters, as opposed to your suggestion which is 18. Quite possibly, re-nomatch is easier to type than a\\` (or whatever). This ease of typing is important, because it encourages hackers to use it rather than typing out the shorter thing. -- Alan Mackenzie (Nuremberg, Germany).