From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Alan Mackenzie Newsgroups: gmane.emacs.devel Subject: Re: "Raw" string literals for elisp Date: Wed, 8 Sep 2021 16:01:46 +0000 Message-ID: References: <4209edd83cfee7c84b2d75ebfcd38784fa21b23c.camel@crossproduct.net> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="30242"; mail-complaints-to="usenet@ciao.gmane.io" Cc: emacs-devel@gnu.org, Anna Glasgall , Stefan Monnier To: Mattias =?iso-8859-1?Q?Engdeg=E5rd?= Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Wed Sep 08 18:08:09 2021 Return-path: Envelope-to: ged-emacs-devel@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 1mO07N-0007fb-L6 for ged-emacs-devel@m.gmane-mx.org; Wed, 08 Sep 2021 18:08:09 +0200 Original-Received: from localhost ([::1]:57390 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mO07L-0006dk-NE for ged-emacs-devel@m.gmane-mx.org; Wed, 08 Sep 2021 12:08:07 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:40636) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mO01I-0001aB-9G for emacs-devel@gnu.org; Wed, 08 Sep 2021 12:01:52 -0400 Original-Received: from colin.muc.de ([193.149.48.1]:54615 helo=mail.muc.de) by eggs.gnu.org with smtp (Exim 4.90_1) (envelope-from ) id 1mO01E-0008UO-RS for emacs-devel@gnu.org; Wed, 08 Sep 2021 12:01:52 -0400 Original-Received: (qmail 26135 invoked by uid 3782); 8 Sep 2021 16:01:46 -0000 Original-Received: from acm.muc.de (p4fe15ce6.dip0.t-ipconnect.de [79.225.92.230]) (using STARTTLS) by colin.muc.de (tmda-ofmipd) with ESMTP; Wed, 08 Sep 2021 18:01:46 +0200 Original-Received: (qmail 8028 invoked by uid 1000); 8 Sep 2021 16:01:46 -0000 Content-Disposition: inline In-Reply-To: X-Submission-Agent: TMDA/1.3.x (Ph3nix) X-Primary-Address: acm@muc.de Received-SPF: pass client-ip=193.149.48.1; envelope-from=acm@muc.de; helo=mail.muc.de X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.23 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-mx.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.io gmane.emacs.devel:274365 Archived-At: Hello, Mattias. On Wed, Sep 08, 2021 at 17:27:58 +0200, Mattias Engdegård wrote: > 8 sep. 2021 kl. 16.31 skrev Anna Glasgall : > > Cards on the table here: yes, regexes are 99.999% of the motivation > > here > Elisp actually has a much better regexp syntax than most other languages: > > "\\(\\\\\\\\\\)\\(?:\\(\\\\\\\\\\)\\|\\((\\(?:\\?[0-9]*:\\)?\\|[|)]\\)\\)" > Today that would be written > (rx (group "\\\\") > (or (group "\\\\") > (group > (or (seq "(" > (? "?" (* digit) ":")) > (in ")|"))))) > which is much more readable and maintainable and less error-prone than > what you would get with a new string syntax. It is more readable in the same way Cobol was very readable; each small grouping of text is immediately understandable. But the thing as a whole? The rx form of that regexp takes up 6 lines, the string form 1 line. If there are several regexps in a function rx can lead to a lot of bloat. Having the function fit entirely on one's screen contributes a lot towards readability and maintainability. It is true the rx form could be squashed onto 1 or 2 lines, but then that readability is lost. I have nothing against people who want to use rx, but personally, I prefer the string form. How much better a raw string form would be is difficult to say. -- Alan Mackenzie (Nuremberg, Germany).