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: Applying print-length to (length string) is suboptimal. Date: Mon, 18 Sep 2023 09:46:14 +0000 Message-ID: References: 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="38600"; 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 Mon Sep 18 11:47:21 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 1qiAqf-0009sq-CB for ged-emacs-devel@m.gmane-mx.org; Mon, 18 Sep 2023 11:47:21 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qiApx-0006Vu-Kj; Mon, 18 Sep 2023 05:46:37 -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 1qiApk-0006HV-6x for emacs-devel@gnu.org; Mon, 18 Sep 2023 05:46:31 -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 1qiApg-0001G5-0r for emacs-devel@gnu.org; Mon, 18 Sep 2023 05:46:22 -0400 Original-Received: (qmail 7554 invoked by uid 3782); 18 Sep 2023 11:46:16 +0200 Original-Received: from acm.muc.de (pd953a7f6.dip0.t-ipconnect.de [217.83.167.246]) (using STARTTLS) by colin.muc.de (tmda-ofmipd) with ESMTP; Mon, 18 Sep 2023 11:46:15 +0200 Original-Received: (qmail 7172 invoked by uid 1000); 18 Sep 2023 09:46:14 -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=193.149.48.3; 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:310689 Archived-At: Hello, Emacs. On Sun, Sep 17, 2023 at 19:57:07 +0000, Alan Mackenzie wrote: > 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? I'm now convinced this is the right way to fix bug #65680, and also the right thing to do generally. So I'm intending to apply the following patch (together with a corresponding amendment to cl-print-tests.el): diff --git a/lisp/emacs-lisp/cl-print.el b/lisp/emacs-lisp/cl-print.el index 71929caabb8..437000ba2a7 100644 --- a/lisp/emacs-lisp/cl-print.el +++ b/lisp/emacs-lisp/cl-print.el @@ -264,27 +264,17 @@ cl-print--struct-contents (cl-defmethod cl-print-object ((object string) stream) (unless stream (setq stream standard-output)) (let* ((has-properties (or (text-properties-at 0 object) - (next-property-change 0 object))) - (len (length object)) - (limit (if (natnump print-length) (min print-length len) len))) + (next-property-change 0 object)))) (if (and has-properties cl-print--depth (natnump print-level) (> cl-print--depth print-level)) (cl-print-insert-ellipsis object nil stream) - ;; Print all or part of the string + ;; Print the string. (when has-properties (princ "#(" stream)) - (if (= limit len) - (prin1 (if has-properties (substring-no-properties object) object) - stream) - (let ((part (concat (substring-no-properties object 0 limit) "..."))) - (prin1 part stream) - (when (bufferp stream) - (with-current-buffer stream - (cl-print-propertize-ellipsis object limit - (- (point) 4) - (- (point) 1) stream))))) + (prin1 (if has-properties (substring-no-properties object) object) + stream) ;; Print the property list. (when has-properties (cl-print--string-props object 0 stream) .. Does anybody have any objections? -- Alan Mackenzie (Nuremberg, Germany).