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: Applying print-length to (length string) is suboptimal. Date: Sun, 17 Sep 2023 19:57:07 +0000 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="432"; mail-complaints-to="usenet@ciao.gmane.io" To: emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Sun Sep 17 21:58:17 2023 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 1qhxuK-000ASE-Uw for ged-emacs-devel@m.gmane-mx.org; Sun, 17 Sep 2023 21:58:16 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qhxtO-0002uM-9M; Sun, 17 Sep 2023 15:57:18 -0400 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 1qhxtM-0002tp-C8 for emacs-devel@gnu.org; Sun, 17 Sep 2023 15:57:16 -0400 Original-Received: from mail.muc.de ([193.149.48.3]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qhxtJ-0005mZ-C9 for emacs-devel@gnu.org; Sun, 17 Sep 2023 15:57:15 -0400 Original-Received: (qmail 47624 invoked by uid 3782); 17 Sep 2023 21:57:09 +0200 Original-Received: from acm.muc.de (p4fe152cb.dip0.t-ipconnect.de [79.225.82.203]) (using STARTTLS) by colin.muc.de (tmda-ofmipd) with ESMTP; Sun, 17 Sep 2023 21:57:08 +0200 Original-Received: (qmail 13613 invoked by uid 1000); 17 Sep 2023 19:57:07 -0000 Content-Disposition: inline X-Submission-Agent: TMDA/1.3.x (Ph3nix) X-Primary-Address: acm@muc.de Received-SPF: pass client-ip=193.149.48.3; 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_PASS=-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: 2.1.29 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-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.devel:310678 Archived-At: Hello, Emacs. Also with reference to bug #65680. In cl-print-object (lisp/emacs-lisp/cl-print.el), the version for strings, print-length is taken as a bound on the length of the string to be printed. Why? The whole idea of print-length (and print-level) is, as far as I can make out, to prevent infinite printing when there's a circular list, for example. This cannot occur for strings. This use of print-length is relatively recent, originating in this commit: commit 8a7620955b4d859caecd9a5dc9f2a986baf994fd Author: Gemini Lasswell Date: Fri Jun 15 10:26:13 2018 -0700 Add methods for strings to cl-print print-length is not used in the function prin1 (as contrasted with cl-prin1). The problem with using print-length for the max. string length is that it is not designed for this. When print-length is, say, 50, almost any list or vector can be printed in full, going up to several hundred printed characters. With a string, the string gets rudely truncated at a mere 50 characters, which is rarely wanted. This is a problem with the error message at the top of a backtrace, where cl-print-string-with-limit limits print-length to a maximum of 50 (See bug #65680). What do people think of removing this observance of print-length from the string version of cl-print-object? -- Alan Mackenzie (Nuremberg, Germany).