From unknown Tue Jun 17 22:28:44 2025 X-Loop: help-debbugs@gnu.org Subject: bug#55395: What does (1 2 3 . #2) mean? Resent-From: Mattias =?UTF-8?Q?Engdeg=C3=A5rd?= Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Fri, 13 May 2022 11:41:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: report 55395 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: To: 55395@debbugs.gnu.org X-Debbugs-Original-To: bug-gnu-emacs@gnu.org Received: via spool by submit@debbugs.gnu.org id=B.165244205219674 (code B ref -1); Fri, 13 May 2022 11:41:01 +0000 Received: (at submit) by debbugs.gnu.org; 13 May 2022 11:40:52 +0000 Received: from localhost ([127.0.0.1]:43037 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1npTfA-00057G-Aa for submit@debbugs.gnu.org; Fri, 13 May 2022 07:40:52 -0400 Received: from lists.gnu.org ([209.51.188.17]:37244) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1npTf9-000579-DD for submit@debbugs.gnu.org; Fri, 13 May 2022 07:40:51 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:46636) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1npTf9-00088n-6f for bug-gnu-emacs@gnu.org; Fri, 13 May 2022 07:40:51 -0400 Received: from mail1448c50.megamailservers.eu ([91.136.14.48]:58096 helo=mail265c50.megamailservers.eu) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1npTf5-0007sr-Ov for bug-gnu-emacs@gnu.org; Fri, 13 May 2022 07:40:50 -0400 X-Authenticated-User: mattiase@bredband.net DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=megamailservers.eu; s=maildub; t=1652441556; bh=HsYx8ZyZPXmKdd+srh2sjIXA6QATRhdgKCR/ONylZsY=; h=From:Subject:Date:To:From; b=e/DVgB7dR8TxrSeJPNND2HAZFjDsOAkl4YFrWK5fDOJGzME2yrRmiiYkeVmsO3BcG ZBsTb8yRdYVluFYEvLW/i6Rc0tFUvrSDsw8loBGB/BgJ4fO5tR16y68V1Ujz4OjPDW gTEtFocMn7j24lZdj57XTFdUcQyLeKj76iqxJEJ4= Feedback-ID: mattiase@acm.or Received: from smtpclient.apple (c188-150-171-71.bredband.tele2.se [188.150.171.71]) (authenticated bits=0) by mail265c50.megamailservers.eu (8.14.9/8.13.1) with ESMTP id 24DBWYbx028640 for ; Fri, 13 May 2022 11:32:36 +0000 From: Mattias =?UTF-8?Q?Engdeg=C3=A5rd?= Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Mime-Version: 1.0 (Mac OS X Mail 14.0 \(3654.120.0.1.13\)) Message-Id: <4B70C9BE-B784-4B74-A081-7A8B3F8D5136@acm.org> Date: Fri, 13 May 2022 13:32:34 +0200 X-Mailer: Apple Mail (2.3654.120.0.1.13) X-CTCH-RefID: str=0001.0A742F17.627E41D4.0038, ss=1, re=0.000, recu=0.000, reip=0.000, cl=1, cld=1, fgs=0 X-CTCH-VOD: Unknown X-CTCH-Spam: Unknown X-CTCH-Score: 0.000 X-CTCH-Rules: X-CTCH-Flags: 0 X-CTCH-ScoreCust: 0.000 X-Origin-Country: SE Received-SPF: softfail client-ip=91.136.14.48; envelope-from=mattiase@acm.org; helo=mail265c50.megamailservers.eu X-Spam_score_int: -11 X-Spam_score: -1.2 X-Spam_bar: - X-Spam_report: (-1.2 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, SPF_HELO_NONE=0.001, SPF_SOFTFAIL=0.665, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=no autolearn_force=no X-Spam_action: no action X-Spam-Score: -1.3 (-) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: -2.3 (--) What, exactly, does the #N print notation mean (with print-circle=3Dnil)? Let's define (rho LEAD LOOP) as the iota list that has a loop LOOP long = after LEAD initial elements: (defun rho (lead loop) (let ((l (number-sequence 1 (+ lead loop)))) (setcdr (nthcdr (+ lead loop -1) l) (nthcdr lead l)) l)) Then we have: (rho 0 1) =3D> (1 . #0) (rho 0 2) =3D> (1 2 1 2 . #2) (rho 0 3) =3D> (1 2 3 1 2 . #2) (rho 0 4) =3D> (1 2 3 4 1 2 3 4 1 2 . #5) (rho 0 5) =3D> (1 2 3 4 5 1 2 3 4 5 1 . #5) (rho 1 4) =3D> (1 2 3 4 5 2 3 4 5 2 . #5) (rho 4 1) =3D> (1 2 3 4 5 5 5 . #3) and so on. The pattern is not obvious to me. It may have made more sense before the switch of cycle-detection = algorithm from Floyd to Brent. This can be fixed by hand-coding the list = iteration and explicitly remembering the index of the tortoise, but = would that be correct? What's the spec? If #N means 'Nth object from the top along the path to the current = object, starting at 0' then we should have (rho 2 3) =3D> (1 2 3 4 5 . #2) (list (rho 2 3)) =3D> ((1 2 3 4 5 . #3)) ie, adding the print depth to the index in the list. Do you agree? From unknown Tue Jun 17 22:28:44 2025 X-Loop: help-debbugs@gnu.org Subject: bug#55395: What does (1 2 3 . #2) mean? Resent-From: Lars Ingebrigtsen Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Fri, 13 May 2022 15:23:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 55395 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: To: Mattias =?UTF-8?Q?Engdeg=C3=A5rd?= Cc: 55395@debbugs.gnu.org, Stefan Monnier Received: via spool by 55395-submit@debbugs.gnu.org id=B55395.165245534610157 (code B ref 55395); Fri, 13 May 2022 15:23:02 +0000 Received: (at 55395) by debbugs.gnu.org; 13 May 2022 15:22:26 +0000 Received: from localhost ([127.0.0.1]:44609 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1npX7a-0002dl-7n for submit@debbugs.gnu.org; Fri, 13 May 2022 11:22:26 -0400 Received: from quimby.gnus.org ([95.216.78.240]:38692) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1npX7Z-0002dV-75 for 55395@debbugs.gnu.org; Fri, 13 May 2022 11:22:25 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gnus.org; s=20200322; h=Content-Transfer-Encoding:Content-Type:MIME-Version:Message-ID :In-Reply-To:Date:References:Subject:Cc:To:From:Sender:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=wh7aUAW5EiIGtGnrLiJyBR4B71+5aJ3/ARis/ADol5M=; b=b07IHX4IF56vZIAx0cExWM2wB/ 59A6iTSQ6vSg085trSEH+QKsuuDk1Pv4IU6M8ngf/ThjPoAZmdvyXdKxGJyAmLXZ8p/5gPJ69kPbM PYbgy5an9H+0lW2w8TCdHJzpny5fWffl6qq4VhJL3CCesRLi0S/hetn86FenqihgZQCI=; Received: from [84.212.220.105] (helo=xo) by quimby.gnus.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1npX7O-00020w-1j; Fri, 13 May 2022 17:22:16 +0200 From: Lars Ingebrigtsen References: <4B70C9BE-B784-4B74-A081-7A8B3F8D5136@acm.org> X-Now-Playing: Colourbox's _Colourbox (PolyGram)_: "Baby I Love You So" Date: Fri, 13 May 2022 17:22:13 +0200 In-Reply-To: <4B70C9BE-B784-4B74-A081-7A8B3F8D5136@acm.org> ("Mattias =?UTF-8?Q?Engdeg=C3=A5rd?="'s message of "Fri, 13 May 2022 13:32:34 +0200") Message-ID: <87ilq931ay.fsf@gnus.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/29.0.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Spam-Report: Spam detection software, running on the system "quimby.gnus.org", has NOT identified this incoming email as spam. The original message has been attached to this so you can view it or label similar future email. If you have any questions, see @@CONTACT_ADDRESS@@ for details. Content preview: Mattias =?UTF-8?Q?Engdeg=C3=A5rd?= writes: > It may have made more sense before the switch of cycle-detection algorithm from Floyd to Brent. This can be fixed by hand-coding the list iteration and explicitly remembering the index of the tortoi [...] Content analysis details: (-2.9 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] X-Spam-Score: -2.3 (--) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: -3.3 (---) Mattias Engdeg=C3=A5rd writes: > It may have made more sense before the switch of cycle-detection algorith= m from Floyd to Brent. This can be fixed by hand-coding the list iteration = and explicitly remembering the index of the tortoise, but would that be cor= rect? What's the spec? I don't think I've ever considered #x to be meaningful outside of print-circle, but I guess if we wanted to have some semantics here, I think I would have expected the index of the tortoise? But... > If #N means 'Nth object from the top along the path to the current object= , starting at 0' then we should have > > (rho 2 3) =3D> (1 2 3 4 5 . #2) > (list (rho 2 3)) =3D> ((1 2 3 4 5 . #3)) > > ie, adding the print depth to the index in the list. Do you agree? I've added Stefan to the CCs; I'm sure he has an opinion. --=20 (domestic pets only, the antidote for overdose, milk.) bloggy blog: http://lars.ingebrigtsen.no From unknown Tue Jun 17 22:28:44 2025 X-Loop: help-debbugs@gnu.org Subject: bug#55395: What does (1 2 3 . #2) mean? Resent-From: Andreas Schwab Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Fri, 13 May 2022 16:09:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 55395 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: To: Mattias =?UTF-8?Q?Engdeg=C3=A5rd?= Cc: 55395@debbugs.gnu.org Received: via spool by 55395-submit@debbugs.gnu.org id=B55395.165245812025600 (code B ref 55395); Fri, 13 May 2022 16:09:01 +0000 Received: (at 55395) by debbugs.gnu.org; 13 May 2022 16:08:40 +0000 Received: from localhost ([127.0.0.1]:44842 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1npXqJ-0006eq-Qh for submit@debbugs.gnu.org; Fri, 13 May 2022 12:08:40 -0400 Received: from mail-out.m-online.net ([212.18.0.9]:57703) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1npXqH-0006eg-2S for 55395@debbugs.gnu.org; Fri, 13 May 2022 12:08:38 -0400 Received: from frontend01.mail.m-online.net (unknown [192.168.8.182]) by mail-out.m-online.net (Postfix) with ESMTP id 4L0D8g4VJRz1qybr; Fri, 13 May 2022 18:08:35 +0200 (CEST) Received: from localhost (dynscan1.mnet-online.de [192.168.6.70]) by mail.m-online.net (Postfix) with ESMTP id 4L0D8g39Hjz1qqkB; Fri, 13 May 2022 18:08:35 +0200 (CEST) X-Virus-Scanned: amavisd-new at mnet-online.de Received: from mail.mnet-online.de ([192.168.8.182]) by localhost (dynscan1.mail.m-online.net [192.168.6.70]) (amavisd-new, port 10024) with ESMTP id Vfgoa4-DvHHn; Fri, 13 May 2022 18:08:34 +0200 (CEST) X-Auth-Info: /YfvqwbtfDzbo2lkZopqlppNxSz06UWEnkMseA7Y3x9+3UmifpaEawjFSInJYjA5 Received: from igel.home (ppp-46-244-176-172.dynamic.mnet-online.de [46.244.176.172]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.mnet-online.de (Postfix) with ESMTPSA; Fri, 13 May 2022 18:08:34 +0200 (CEST) Received: by igel.home (Postfix, from userid 1000) id EC87E2C39F5; Fri, 13 May 2022 18:08:33 +0200 (CEST) From: Andreas Schwab References: <4B70C9BE-B784-4B74-A081-7A8B3F8D5136@acm.org> X-Yow: NANCY!! Why is everything RED?! Date: Fri, 13 May 2022 18:08:33 +0200 In-Reply-To: <4B70C9BE-B784-4B74-A081-7A8B3F8D5136@acm.org> ("Mattias =?UTF-8?Q?Engdeg=C3=A5rd?="'s message of "Fri, 13 May 2022 13:32:34 +0200") Message-ID: <87czghl8ji.fsf@igel.home> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Spam-Score: -0.5 (/) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: -1.5 (-) On Mai 13 2022, Mattias Engdegård wrote: > Let's define (rho LEAD LOOP) as the iota list that has a loop LOOP long after LEAD initial elements: > > (defun rho (lead loop) > (let ((l (number-sequence 1 (+ lead loop)))) > (setcdr (nthcdr (+ lead loop -1) l) (nthcdr lead l)) > l)) > > Then we have: > > (rho 0 1) => (1 . #0) > (rho 0 2) => (1 2 1 2 . #2) > (rho 0 3) => (1 2 3 1 2 . #2) > (rho 0 4) => (1 2 3 4 1 2 3 4 1 2 . #5) > (rho 0 5) => (1 2 3 4 5 1 2 3 4 5 1 . #5) > (rho 1 4) => (1 2 3 4 5 2 3 4 5 2 . #5) > (rho 4 1) => (1 2 3 4 5 5 5 . #3) > > and so on. The pattern is not obvious to me. > > It may have made more sense before the switch of cycle-detection algorithm from Floyd to Brent. This can be fixed by hand-coding the list iteration and explicitly remembering the index of the tortoise, but would that be correct? What's the spec? I don't think there is a defined meaning behind the number, it's more an implementation detail. If you want to have precise cycle detection you need to enable print-circle. -- Andreas Schwab, schwab@linux-m68k.org GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1 "And now for something completely different." From unknown Tue Jun 17 22:28:44 2025 X-Loop: help-debbugs@gnu.org Subject: bug#55395: What does (1 2 3 . #2) mean? Resent-From: Stefan Monnier Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Fri, 13 May 2022 17:22:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 55395 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: To: Lars Ingebrigtsen Cc: 55395@debbugs.gnu.org, Mattias =?UTF-8?Q?Engdeg=C3=A5rd?= Received: via spool by 55395-submit@debbugs.gnu.org id=B55395.165246246210534 (code B ref 55395); Fri, 13 May 2022 17:22:02 +0000 Received: (at 55395) by debbugs.gnu.org; 13 May 2022 17:21:02 +0000 Received: from localhost ([127.0.0.1]:44935 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1npYyM-0002jp-6A for submit@debbugs.gnu.org; Fri, 13 May 2022 13:21:02 -0400 Received: from mailscanner.iro.umontreal.ca ([132.204.25.50]:47384) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1npYyK-0002iy-Dm for 55395@debbugs.gnu.org; Fri, 13 May 2022 13:21:00 -0400 Received: from pmg2.iro.umontreal.ca (localhost.localdomain [127.0.0.1]) by pmg2.iro.umontreal.ca (Proxmox) with ESMTP id 6B3AB806F8; Fri, 13 May 2022 13:20:54 -0400 (EDT) Received: from mail01.iro.umontreal.ca (unknown [172.31.2.1]) by pmg2.iro.umontreal.ca (Proxmox) with ESMTP id 072EA80390; Fri, 13 May 2022 13:20:53 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=iro.umontreal.ca; s=mail; t=1652462453; bh=wwl+HdjokZCX0CMorQ8lDP3LJUMuA9XXC6o0ZLOIezA=; h=From:To:Cc:Subject:References:Date:In-Reply-To:From; b=TtDybZ3FGCsI26a3Bg/IS80Rf5Duy+/d5CPyR8ajcHx9phoEeZa8WakaqQa2xjflH FDpML4JF3nEpbU5yycvUr28fgGXCM9YSw4P6Ca3yYsrZAV94/hhIMzbFFhfoBTCu+c pUL3/2fPNscO7JXz340DNj9pO4huU0ygtHybRSnuL/1dfLxmL6sHMWg0MJ8XZyF9s0 KiDSjkE6s1bdD2mbZ0U+brOGhLKcUwd8j6dKffJ7xwGi/DG60I99/z72HL0ZRpINvn xUTzqzS9FjUGuLMeyxBqRlszx8UtyocTJaBrtbR950+l9lipore89UhGHchU5UK2dw D5+bpxp7lf49A== Received: from pastel (unknown [45.72.221.51]) by mail01.iro.umontreal.ca (Postfix) with ESMTPSA id 9CDAE120837; Fri, 13 May 2022 13:20:52 -0400 (EDT) From: Stefan Monnier Message-ID: References: <4B70C9BE-B784-4B74-A081-7A8B3F8D5136@acm.org> <87ilq931ay.fsf@gnus.org> Date: Fri, 13 May 2022 13:20:51 -0400 In-Reply-To: <87ilq931ay.fsf@gnus.org> (Lars Ingebrigtsen's message of "Fri, 13 May 2022 17:22:13 +0200") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/29.0.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable X-SPAM-INFO: Spam detection results: 0 ALL_TRUSTED -1 Passed through trusted hosts only via SMTP AWL -0.054 Adjusted score from AWL reputation of From: address BAYES_00 -1.9 Bayes spam probability is 0 to 1% DKIM_SIGNED 0.1 Message has a DKIM or DK signature, not necessarily valid DKIM_VALID -0.1 Message has at least one valid DKIM or DK signature DKIM_VALID_AU -0.1 Message has a valid DKIM or DK signature from author's domain T_SCC_BODY_TEXT_LINE -0.01 - X-SPAM-LEVEL: X-Spam-Score: -2.3 (--) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: -3.3 (---) >> It may have made more sense before the switch of cycle-detection algorit= hm >> from Floyd to Brent. This can be fixed by hand-coding the list iteration >> and explicitly remembering the index of the tortoise, but would that be >> correct? What's the spec? > > I don't think I've ever considered #x to be meaningful outside of > print-circle, but I guess if we wanted to have some semantics here, I > think I would have expected the index of the tortoise? But... Agreed (and agreed with Andreas as well). The main goal is to avoid inf-looping and the #NNN chosen is somewhat arbitrary. I don't think it's worth it to try and make those #NNN more precise. If the arbitrariness of the specific #NNN chosen is a problem, we could replace it with a fixed `#=A1cycle!` or something like that (or if we want it to be more user-readable we could print something like #cycle: where OBJ is the first N layers of the rest of the cycle, like (rho 0 2) =3D> (1 2 1 2 . #cycle:(1 2 1 ...)) I'm personally more bothered by the fact that those #NNN use exactly the same syntax as used with `print-circle` yet they don't have the same semantics. Stefan From unknown Tue Jun 17 22:28:44 2025 X-Loop: help-debbugs@gnu.org Subject: bug#55395: What does (1 2 3 . #2) mean? Resent-From: Lars Ingebrigtsen Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Fri, 13 May 2022 19:55:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 55395 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: To: Stefan Monnier Cc: 55395@debbugs.gnu.org, Mattias =?UTF-8?Q?Engdeg=C3=A5rd?= Received: via spool by 55395-submit@debbugs.gnu.org id=B55395.165247168429672 (code B ref 55395); Fri, 13 May 2022 19:55:01 +0000 Received: (at 55395) by debbugs.gnu.org; 13 May 2022 19:54:44 +0000 Received: from localhost ([127.0.0.1]:45112 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1npbN6-0007iV-0T for submit@debbugs.gnu.org; Fri, 13 May 2022 15:54:44 -0400 Received: from quimby.gnus.org ([95.216.78.240]:41256) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1npbN4-0007iF-3m for 55395@debbugs.gnu.org; Fri, 13 May 2022 15:54:42 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gnus.org; s=20200322; h=Content-Type:MIME-Version:Message-ID:In-Reply-To:Date: References:Subject:Cc:To:From:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=3S5PTOedpkSDirGmAIUAjVt9cM6X6WliiYZmhZo02PE=; b=rdpE6KmXnOlWVEu/jJ6J1x3K4F RSge0iTvzkSqBKT16WaAZYb5iQM7nsTi8UgfNLJOIVXReuFnIC6ghU+0xg3O/+DpSAAhUH4DHu6K/ 9xghlQU3YevQhCmfOL1plJ3CdjObkdz5O4OgclGgzlICUFTqXlcC3jGkPAy5Xus4XTKc=; Received: from [84.212.220.105] (helo=xo) by quimby.gnus.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1npbMt-00045H-F0; Fri, 13 May 2022 21:54:33 +0200 From: Lars Ingebrigtsen References: <4B70C9BE-B784-4B74-A081-7A8B3F8D5136@acm.org> <87ilq931ay.fsf@gnus.org> X-Now-Playing: Fairport Convention's _(guitar, vocal)_: "Sweet Little Rock 'n' Roller" Date: Fri, 13 May 2022 21:54:30 +0200 In-Reply-To: (Stefan Monnier's message of "Fri, 13 May 2022 13:20:51 -0400") Message-ID: <87ee0xyzrd.fsf@gnus.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/29.0.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Spam-Report: Spam detection software, running on the system "quimby.gnus.org", has NOT identified this incoming email as spam. The original message has been attached to this so you can view it or label similar future email. If you have any questions, see @@CONTACT_ADDRESS@@ for details. Content preview: Stefan Monnier writes: > Agreed (and agreed with Andreas as well). > The main goal is to avoid inf-looping and the #NNN chosen is > somewhat arbitrary. > > I don't think it's worth it to try and make those #NNN more precise [...] Content analysis details: (-2.9 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] X-Spam-Score: -2.3 (--) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: -3.3 (---) Stefan Monnier writes: > Agreed (and agreed with Andreas as well). > The main goal is to avoid inf-looping and the #NNN chosen is > somewhat arbitrary. > > I don't think it's worth it to try and make those #NNN more precise. So it seems like everybody basically agrees on that... so if Mattias wants to implement something here to give them some semantics, he can pretty much choose whatever he wants? Or just document that there's really no semantics here without print-circle, if he prefers. -- (domestic pets only, the antidote for overdose, milk.) bloggy blog: http://lars.ingebrigtsen.no From unknown Tue Jun 17 22:28:44 2025 X-Loop: help-debbugs@gnu.org Subject: bug#55395: What does (1 2 3 . #2) mean? Resent-From: Mattias =?UTF-8?Q?Engdeg=C3=A5rd?= Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Fri, 13 May 2022 20:02:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 55395 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: To: Stefan Monnier Cc: 55395@debbugs.gnu.org, Lars Ingebrigtsen Received: via spool by 55395-submit@debbugs.gnu.org id=B55395.16524721134800 (code B ref 55395); Fri, 13 May 2022 20:02:01 +0000 Received: (at 55395) by debbugs.gnu.org; 13 May 2022 20:01:53 +0000 Received: from localhost ([127.0.0.1]:45116 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1npbU0-0001Ey-OJ for submit@debbugs.gnu.org; Fri, 13 May 2022 16:01:53 -0400 Received: from mail205c50.megamailservers.eu ([91.136.10.215]:53196 helo=mail193c50.megamailservers.eu) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1npbTy-0001Bf-3l for 55395@debbugs.gnu.org; Fri, 13 May 2022 16:01:51 -0400 X-Authenticated-User: mattiase@bredband.net DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=megamailservers.eu; s=maildub; t=1652472107; bh=SIK8ZfzU00JmQULaXrktkc5EWc/gsj1VuBReHIO+9T0=; h=Subject:From:In-Reply-To:Date:Cc:References:To:From; b=Yr8wzci2nBxhwpey8ZTvWglYGyb81Eek9EZnSJW3Uv2h9PpAQ2mNHYybP1Gjq2Cb5 dVCllGUteicnIBjgGubZDT/vttdCXqDp1edLX5eZMUL+TcmQLTo1o/Q3ZDlUvC/BNC Fem9AMB5ibZuS/nU6gto8F018+jNT02NfZKN94Yc= Feedback-ID: mattiase@acm.or Received: from smtpclient.apple (c188-150-171-71.bredband.tele2.se [188.150.171.71]) (authenticated bits=0) by mail193c50.megamailservers.eu (8.14.9/8.13.1) with ESMTP id 24DK1jKp021497; Fri, 13 May 2022 20:01:47 +0000 Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 14.0 \(3654.120.0.1.13\)) From: Mattias =?UTF-8?Q?Engdeg=C3=A5rd?= In-Reply-To: Date: Fri, 13 May 2022 22:01:44 +0200 Content-Transfer-Encoding: quoted-printable Message-Id: <715F3D50-7D11-47CF-A34B-6532F1F508D7@acm.org> References: <4B70C9BE-B784-4B74-A081-7A8B3F8D5136@acm.org> <87ilq931ay.fsf@gnus.org> X-Mailer: Apple Mail (2.3654.120.0.1.13) X-CTCH-RefID: str=0001.0A742F17.627EB92B.00CB, ss=1, re=0.000, recu=0.000, reip=0.000, cl=1, cld=1, fgs=0 X-CTCH-VOD: Unknown X-CTCH-Spam: Unknown X-CTCH-Score: 0.000 X-CTCH-Rules: X-CTCH-Flags: 0 X-CTCH-ScoreCust: 0.000 X-Origin-Country: SE X-Spam-Score: 0.3 (/) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: -0.7 (/) 13 maj 2022 kl. 19.20 skrev Stefan Monnier : > The main goal is to avoid inf-looping and the #NNN chosen is > somewhat arbitrary. It seems to have sort-of worked before and was broken, inadvertently and = with the best intentions, by a later change. Additionally the #N value appears to be correct for other object types. = For example, [a [b #1=3D[[c #1# d]]]] is printed as [a [b [[c #2 d]]]] which is consistent with the manual. > I don't think it's worth it to try and make those #NNN more precise. I have a simple patch but it is not based on master so it will have to = wait. > I'm personally more bothered by the fact that those #NNN use exactly = the > same syntax as used with `print-circle` yet they don't have the > same semantics. The syntax isn't exactly the same (#N vs #N=3D and #N#) but annoyingly = close. For that matter I would have preferred numbering the other way, starting = at the bottom going up, like de Bruijn indices. That way the numbering = would be local and wouldn't depend on where the circular subtree occurs. = Technically that would be an easy change, and if we agree that the = numbers are unreliable right now, we might as well. From unknown Tue Jun 17 22:28:44 2025 X-Loop: help-debbugs@gnu.org Subject: bug#55395: What does (1 2 3 . #2) mean? Resent-From: Stefan Monnier Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Sat, 14 May 2022 13:46:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 55395 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: To: Mattias =?UTF-8?Q?Engdeg=C3=A5rd?= Cc: 55395@debbugs.gnu.org, Lars Ingebrigtsen Received: via spool by 55395-submit@debbugs.gnu.org id=B55395.165253593628145 (code B ref 55395); Sat, 14 May 2022 13:46:02 +0000 Received: (at 55395) by debbugs.gnu.org; 14 May 2022 13:45:36 +0000 Received: from localhost ([127.0.0.1]:46031 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1nps5Q-0007Js-1M for submit@debbugs.gnu.org; Sat, 14 May 2022 09:45:36 -0400 Received: from mailscanner.iro.umontreal.ca ([132.204.25.50]:12220) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1nps5O-0007JZ-4y for 55395@debbugs.gnu.org; Sat, 14 May 2022 09:45:34 -0400 Received: from pmg2.iro.umontreal.ca (localhost.localdomain [127.0.0.1]) by pmg2.iro.umontreal.ca (Proxmox) with ESMTP id 3BAD880065; Sat, 14 May 2022 09:45:28 -0400 (EDT) Received: from mail01.iro.umontreal.ca (unknown [172.31.2.1]) by pmg2.iro.umontreal.ca (Proxmox) with ESMTP id 96656802A7; Sat, 14 May 2022 09:45:22 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=iro.umontreal.ca; s=mail; t=1652535922; bh=5HYecQlFK+ohrzXZNHpqPPKcuPA0/Rylr2KceMMZ6Eo=; h=From:To:Cc:Subject:References:Date:In-Reply-To:From; b=geEDekDqsUYREKX+xLfhXWAjVUryBT4EJYw9Rx5RhDmL77ANv8X1z74mzcI4Vkvan KV0lE+pjckvNLavXFqBfojoXztQ5OS+cz9o3MWFfmnN+FH2dEZXSL2taEPKZ69febf oQCYk8JzvCMDxTB+MUaj9KuPBOkUNP+UVzjwU5QW8suML9OwCiVGq3ldzlvtkdPwSf 4BCFnjNqkljt+ycz+BfQpjpMqaQecMjUZFdfkVkQaXKsQwBCZXfKSHCmZlflo79JBY SBinpdbYuuxssdn+c1ib5j4MMrVRCJ9+IbFQkR/ApTMrj+J0bn2fc+BFXJLZmfsOrV 1Nc7HzGAek4Eg== Received: from alfajor (modemcable034.207-20-96.mc.videotron.ca [96.20.207.34]) by mail01.iro.umontreal.ca (Postfix) with ESMTPSA id 692D81208BF; Sat, 14 May 2022 09:45:22 -0400 (EDT) From: Stefan Monnier Message-ID: References: <4B70C9BE-B784-4B74-A081-7A8B3F8D5136@acm.org> <87ilq931ay.fsf@gnus.org> <715F3D50-7D11-47CF-A34B-6532F1F508D7@acm.org> Date: Sat, 14 May 2022 09:45:15 -0400 In-Reply-To: <715F3D50-7D11-47CF-A34B-6532F1F508D7@acm.org> ("Mattias =?UTF-8?Q?Engdeg=C3=A5rd?="'s message of "Fri, 13 May 2022 22:01:44 +0200") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/29.0.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-SPAM-INFO: Spam detection results: 0 ALL_TRUSTED -1 Passed through trusted hosts only via SMTP AWL -0.099 Adjusted score from AWL reputation of From: address BAYES_00 -1.9 Bayes spam probability is 0 to 1% DKIM_SIGNED 0.1 Message has a DKIM or DK signature, not necessarily valid DKIM_VALID -0.1 Message has at least one valid DKIM or DK signature DKIM_VALID_AU -0.1 Message has a valid DKIM or DK signature from author's domain T_SCC_BODY_TEXT_LINE -0.01 - X-SPAM-LEVEL: X-Spam-Score: -2.3 (--) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: -3.3 (---) >> The main goal is to avoid inf-looping and the #NNN chosen is >> somewhat arbitrary. > It seems to have sort-of worked before and was broken, inadvertently and > with the best intentions, by a later change. > > Additionally the #N value appears to be correct for other object types. For example, > > [a [b #1=[[c #1# d]]]] > > is printed as > > [a [b [[c #2 d]]]] > > which is consistent with the manual. I do have the impression that it used to be "correct", but I can't remember of a single time where I actually made use of that NNN. And even if you know what it means and it works correctly, it's pretty hard for a normal human to correctly count the depth starting from the root. I suspect if we want to "do better", printing "the beginning" of the object to which we're looping (and saying explicitly that there's a cycle) will be a lot more useful to the average user. [ Or we could even print "the period" rather than "the beginning". ] >> I'm personally more bothered by the fact that those #NNN use exactly the >> same syntax as used with `print-circle` yet they don't have the >> same semantics. > The syntax isn't exactly the same (#N vs #N= and #N#) but annoyingly close. Indeed, it's not as bad as I remembered. > For that matter I would have preferred numbering the other way, starting at > the bottom going up, like de Bruijn indices. I love&hate de Bruijn indices as much as the next guy, but they're not human-friendly (even more than the "like de Bruijn levels" we currently use). Stefan From unknown Tue Jun 17 22:28:44 2025 X-Loop: help-debbugs@gnu.org Subject: bug#55395: What does (1 2 3 . #2) mean? Resent-From: Mattias =?UTF-8?Q?Engdeg=C3=A5rd?= Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Wed, 18 May 2022 14:31:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 55395 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: To: Stefan Monnier Cc: 55395@debbugs.gnu.org, Lars Ingebrigtsen Received: via spool by 55395-submit@debbugs.gnu.org id=B55395.165288420617451 (code B ref 55395); Wed, 18 May 2022 14:31:02 +0000 Received: (at 55395) by debbugs.gnu.org; 18 May 2022 14:30:06 +0000 Received: from localhost ([127.0.0.1]:33149 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1nrKgf-0004Wz-OS for submit@debbugs.gnu.org; Wed, 18 May 2022 10:30:06 -0400 Received: from mail1446c50.megamailservers.eu ([91.136.14.46]:44332 helo=mail265c50.megamailservers.eu) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1nrKgd-0004Ts-1C for 55395@debbugs.gnu.org; Wed, 18 May 2022 10:30:04 -0400 X-Authenticated-User: mattiase@bredband.net DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=megamailservers.eu; s=maildub; t=1652884196; bh=AkoR2KV03hTvXBXqJUSLGLi0/mBk6TCyBF4Pc/iYBRg=; h=From:Subject:Date:In-Reply-To:Cc:To:References:From; b=IiQhb9wOumxZVxRBDSnY4TBSYmvGXZ+Pke4alygp/MKkdw3+P/AjQ/iz8MxpclXWC 7fdd68lygqi5ZD8FSq0D2Vcoe4GHvv73F1SYAAq7v4RM0j/cTue9HketiSlk48Mxbn tGLMtIeHObLrZfOWJY/fgUFTqbSqFOVHeZnbtXIM= Feedback-ID: mattiase@acm.or Received: from smtpclient.apple (c188-150-171-71.bredband.tele2.se [188.150.171.71]) (authenticated bits=0) by mail265c50.megamailservers.eu (8.14.9/8.13.1) with ESMTP id 24IETqMf005775; Wed, 18 May 2022 14:29:54 +0000 From: Mattias =?UTF-8?Q?Engdeg=C3=A5rd?= Message-Id: <86345ABE-C19C-4096-8550-05E5B78D6C3A@acm.org> Content-Type: multipart/mixed; boundary="Apple-Mail=_9C60AD69-423C-4E73-823B-DAA20C4ABAB0" Mime-Version: 1.0 (Mac OS X Mail 14.0 \(3654.120.0.1.13\)) Date: Wed, 18 May 2022 16:29:51 +0200 In-Reply-To: References: <4B70C9BE-B784-4B74-A081-7A8B3F8D5136@acm.org> <87ilq931ay.fsf@gnus.org> <715F3D50-7D11-47CF-A34B-6532F1F508D7@acm.org> X-Mailer: Apple Mail (2.3654.120.0.1.13) X-CTCH-RefID: str=0001.0A742F1B.628502E4.000E, ss=1, re=0.000, recu=0.000, reip=0.000, cl=1, cld=1, fgs=0 X-CTCH-VOD: Unknown X-CTCH-Spam: Unknown X-CTCH-Score: 0.000 X-CTCH-Rules: X-CTCH-Flags: 0 X-CTCH-ScoreCust: 0.000 X-Origin-Country: SE X-Spam-Score: 1.3 (+) X-Spam-Report: Spam detection software, running on the system "debbugs.gnu.org", has NOT identified this incoming email as spam. The original message has been attached to this so you can view it or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: 14 maj 2022 kl. 15.45 skrev Stefan Monnier : > I do have the impression that it used to be "correct", but I can't > remember of a single time where I actually made use of that NNN. > > And even if you know what it means and it works correctly, i [...] Content analysis details: (1.3 points, 10.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record 1.0 SPF_SOFTFAIL SPF: sender does not match SPF record (softfail) -0.0 T_SCC_BODY_TEXT_LINE No description available. 0.3 KHOP_HELO_FCRDNS Relay HELO differs from its IP's reverse DNS X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: -0.0 (/) --Apple-Mail=_9C60AD69-423C-4E73-823B-DAA20C4ABAB0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii 14 maj 2022 kl. 15.45 skrev Stefan Monnier : > I do have the impression that it used to be "correct", but I can't > remember of a single time where I actually made use of that NNN. >=20 > And even if you know what it means and it works correctly, it's pretty > hard for a normal human to correctly count the depth starting from > the root. It is. Counting upwards from a leaf seems slightly easier. Perhaps these attempts to generate a meaningful circularity reference is = a fool's errand and we should just go with #!circle! or something = similar. Anyway, I'm attaching a patch that tries to put some meaning back in the = ` . #N` notation: it's an index into the same list, as it used to be, I = think, prior to the switch from Floyd to Brent. This is done by keeping = track of the index of the tortoise at all times, which isn't very = expensive at all. Without the patch: (rho 4 1) =3D> (1 2 3 4 5 5 5 . #3) With the patch: (rho 4 1) =3D> (1 2 3 4 5 5 5 . #6) which should be a mild improvement. It's still ambiguous: (1 1 . #1) could mean either #1=3D(1 . #1#) or #1=3D(1 1 . #1#) and [(1 2 3 . #0)] could mean either [#1=3D(1 2 3 . #1#)] or #1=3D[(1 2 3 . #1#)] but maybe it's less wrong, with room for future improvement? --Apple-Mail=_9C60AD69-423C-4E73-823B-DAA20C4ABAB0 Content-Disposition: attachment; filename=circular-list-print-index.diff Content-Type: application/octet-stream; x-unix-mode=0644; name="circular-list-print-index.diff" Content-Transfer-Encoding: 7bit diff --git a/src/print.c b/src/print.c index da4869e8fb..823bc07406 100644 --- a/src/print.c +++ b/src/print.c @@ -2028,12 +2028,12 @@ named_escape (int i) union { struct { Lisp_Object last; /* cons whose car was just printed */ - ptrdiff_t idx; /* index of next element */ - intmax_t maxlen; /* max length (from Vprint_length) */ + intmax_t maxlen; /* max number of elements left to print */ /* state for Brent cycle detection */ Lisp_Object tortoise; /* slow pointer */ ptrdiff_t n; /* tortoise step countdown */ ptrdiff_t m; /* tortoise step period */ + ptrdiff_t tortoise_idx; /* index of tortoise */ } list; struct { Lisp_Object obj; /* object to print after " . " */ @@ -2408,10 +2408,10 @@ print_object (Lisp_Object obj, Lisp_Object printcharfun, bool escapeflag) .type = PE_list, .u.list.last = obj, .u.list.maxlen = print_length, - .u.list.idx = 1, .u.list.tortoise = obj, .u.list.n = 2, .u.list.m = 2, + .u.list.tortoise_idx = 0, }); /* print the car */ obj = XCAR (obj); @@ -2582,10 +2582,8 @@ print_object (Lisp_Object obj, Lisp_Object printcharfun, bool escapeflag) printchar (' ', printcharfun); - /* FIXME: We wouldn't need to keep track of idx if we - count down maxlen instead, and maintain a separate - tortoise index if required. */ - if (e->u.list.idx >= e->u.list.maxlen) + --e->u.list.maxlen; + if (e->u.list.maxlen <= 0) { print_c_string ("...)", printcharfun); --prstack.sp; @@ -2594,22 +2592,21 @@ print_object (Lisp_Object obj, Lisp_Object printcharfun, bool escapeflag) } e->u.list.last = next; - e->u.list.idx++; e->u.list.n--; if (e->u.list.n == 0) { /* Double tortoise update period and teleport it. */ + e->u.list.tortoise_idx += e->u.list.m; e->u.list.m <<= 1; e->u.list.n = e->u.list.m; e->u.list.tortoise = next; } else if (BASE_EQ (next, e->u.list.tortoise)) { - /* FIXME: This #N tail index is bug-compatible with - previous implementations but actually nonsense; + /* FIXME: This #N tail index is somewhat ambiguous; see bug#55395. */ int len = sprintf (buf, ". #%" PRIdMAX ")", - (e->u.list.idx >> 1) - 1); + e->u.list.tortoise_idx); strout (buf, len, len, printcharfun); --prstack.sp; --print_depth; --Apple-Mail=_9C60AD69-423C-4E73-823B-DAA20C4ABAB0-- From unknown Tue Jun 17 22:28:44 2025 X-Loop: help-debbugs@gnu.org Subject: bug#55395: What does (1 2 3 . #2) mean? Resent-From: Stefan Monnier Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Wed, 18 May 2022 21:17:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 55395 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: To: Mattias =?UTF-8?Q?Engdeg=C3=A5rd?= Cc: 55395@debbugs.gnu.org, Lars Ingebrigtsen Received: via spool by 55395-submit@debbugs.gnu.org id=B55395.165290858918798 (code B ref 55395); Wed, 18 May 2022 21:17:02 +0000 Received: (at 55395) by debbugs.gnu.org; 18 May 2022 21:16:29 +0000 Received: from localhost ([127.0.0.1]:33790 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1nrR1w-0004t8-SZ for submit@debbugs.gnu.org; Wed, 18 May 2022 17:16:29 -0400 Received: from mailscanner.iro.umontreal.ca ([132.204.25.50]:50144) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1nrR1v-0004sp-84 for 55395@debbugs.gnu.org; Wed, 18 May 2022 17:16:27 -0400 Received: from pmg1.iro.umontreal.ca (localhost.localdomain [127.0.0.1]) by pmg1.iro.umontreal.ca (Proxmox) with ESMTP id 4480D100596; Wed, 18 May 2022 17:16:21 -0400 (EDT) Received: from mail01.iro.umontreal.ca (unknown [172.31.2.1]) by pmg1.iro.umontreal.ca (Proxmox) with ESMTP id A28CC100139; Wed, 18 May 2022 17:16:19 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=iro.umontreal.ca; s=mail; t=1652908579; bh=EXVTjJ5H9GORKlB25HMQPuqKr4QLw49V8wjKbPrXKx0=; h=From:To:Cc:Subject:References:Date:In-Reply-To:From; b=Rj+ahKiSyBrG8jMLLO7fj3BmRG3GfzJey5/EUA5lH57Cpll2uqo8bBlXJSsS/wUfZ oUliOlPLXS7QuUM0uChs+tvUBJ42oWjvobHssRILT73wexpTKXRBI5vW3kK9BjNXBk SHrfNSpXKMfZIHpYalAtLaFU0AYJDPXZfQPLlAS2NdPDp1DTZ0Bt6Czt6IkJM+HT7U B830qIIxT5mamOIKoJg5A373i/4ghPaWBrbeEUcYx0P5toH1mwpiubGOVJ686WHxnR 96LwCkLRnxfkB5SFIQHmZQEsEsIxItgv709Qov2GBKAaj+e6F5bpK7tq5XiFWWuM7Z 0c2VqskSu81EA== Received: from alfajor (lechon.iro.umontreal.ca [132.204.27.242]) by mail01.iro.umontreal.ca (Postfix) with ESMTPSA id 8F38D120C63; Wed, 18 May 2022 17:16:19 -0400 (EDT) From: Stefan Monnier Message-ID: References: <4B70C9BE-B784-4B74-A081-7A8B3F8D5136@acm.org> <87ilq931ay.fsf@gnus.org> <715F3D50-7D11-47CF-A34B-6532F1F508D7@acm.org> <86345ABE-C19C-4096-8550-05E5B78D6C3A@acm.org> Date: Wed, 18 May 2022 17:16:16 -0400 In-Reply-To: <86345ABE-C19C-4096-8550-05E5B78D6C3A@acm.org> ("Mattias =?UTF-8?Q?Engdeg=C3=A5rd?="'s message of "Wed, 18 May 2022 16:29:51 +0200") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/29.0.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable X-SPAM-INFO: Spam detection results: 0 ALL_TRUSTED -1 Passed through trusted hosts only via SMTP AWL 0.185 Adjusted score from AWL reputation of From: address BAYES_00 -1.9 Bayes spam probability is 0 to 1% DKIM_SIGNED 0.1 Message has a DKIM or DK signature, not necessarily valid DKIM_VALID -0.1 Message has at least one valid DKIM or DK signature DKIM_VALID_AU -0.1 Message has a valid DKIM or DK signature from author's domain T_SCC_BODY_TEXT_LINE -0.01 - X-SPAM-LEVEL: X-Spam-Score: -2.3 (--) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: -3.3 (---) > [(1 2 3 . #0)] > > could mean either > > [#1=3D(1 2 3 . #1#)] > > or > > #1=3D[(1 2 3 . #1#)] AFAIK it *should* mean the latter (#0 is the root of the overall printed object, not just the list). Mattias Engdeg=E5rd [2022-05-18 16:29:51] wrote: > Perhaps these attempts to generate a meaningful circularity reference is > a fool's errand and we should just go with #!circle! or something similar. Yup. But we don't shy away from playing the fools. Stefan From unknown Tue Jun 17 22:28:44 2025 X-Loop: help-debbugs@gnu.org Subject: bug#55395: What does (1 2 3 . #2) mean? 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Content preview: 18 maj 2022 kl. 23.16 skrev Stefan Monnier : > >> [(1 2 3 . #0)] >> >> could mean either >> >> [#1=(1 2 3 . #1#)] >> >> or >> >> #1=[(1 2 3 . #1#)] > > AFAIK it *should* mean [...] Content analysis details: (1.3 points, 10.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record 1.0 SPF_SOFTFAIL SPF: sender does not match SPF record (softfail) -0.0 T_SCC_BODY_TEXT_LINE No description available. 0.3 KHOP_HELO_FCRDNS Relay HELO differs from its IP's reverse DNS X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: -0.0 (/) 18 maj 2022 kl. 23.16 skrev Stefan Monnier : >=20 >> [(1 2 3 . #0)] >>=20 >> could mean either >>=20 >> [#1=3D(1 2 3 . #1#)] >>=20 >> or >>=20 >> #1=3D[(1 2 3 . #1#)] >=20 > AFAIK it *should* mean the latter (#0 is the root of the overall > printed object, not just the list). Yes, but the code was already a bit ambiguous in that respect. We don't = keep track of the cons-level depth when printing; print_depth treats = each list nesting as one step regardless of where in the list the = nesting occurs. I suppose this could be remedied but I'm not going to = work on it right now. The previously attached patch has been pushed to master, on the grounds = that it should be strictly better than what we had before; correctness = should be back at the level before the change in circularity detection = algorithm broke the tail index completely. > Yup. But we don't shy away from playing the fools. You know me, I don't even need to play one. It all comes natural.