From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Lars Ingebrigtsen Newsgroups: gmane.emacs.bugs Subject: bug#26629: 25.1.50; Feature-request: Structure-preserving copying of sequences Date: Fri, 13 May 2022 18:18:09 +0200 Message-ID: <87ee0x1k5a.fsf@gnus.org> References: <874lxepytq.fsf@smtp.1und1.de> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="23007"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/29.0.50 (gnu/linux) Cc: Stefan Monnier , 26629@debbugs.gnu.org To: Tobias Zawada Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Fri May 13 18:44:52 2022 Return-path: Envelope-to: geb-bug-gnu-emacs@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 1npYPL-0005l1-Jp for geb-bug-gnu-emacs@m.gmane-mx.org; Fri, 13 May 2022 18:44:51 +0200 Original-Received: from localhost ([::1]:35160 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1npYPK-0004rW-MF for geb-bug-gnu-emacs@m.gmane-mx.org; Fri, 13 May 2022 12:44:50 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:54876) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1npY0M-0001Sc-Fv for bug-gnu-emacs@gnu.org; Fri, 13 May 2022 12:19:02 -0400 Original-Received: from debbugs.gnu.org ([209.51.188.43]:50969) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1npY0M-0005w8-5k for bug-gnu-emacs@gnu.org; Fri, 13 May 2022 12:19:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1npY0L-0006zU-Va for bug-gnu-emacs@gnu.org; Fri, 13 May 2022 12:19:01 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Lars Ingebrigtsen Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Fri, 13 May 2022 16:19:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 26629 X-GNU-PR-Package: emacs Original-Received: via spool by 26629-submit@debbugs.gnu.org id=B26629.165245870326788 (code B ref 26629); Fri, 13 May 2022 16:19:01 +0000 Original-Received: (at 26629) by debbugs.gnu.org; 13 May 2022 16:18:23 +0000 Original-Received: from localhost ([127.0.0.1]:44863 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1npXzj-0006xy-4R for submit@debbugs.gnu.org; Fri, 13 May 2022 12:18:23 -0400 Original-Received: from quimby.gnus.org ([95.216.78.240]:39356) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1npXzg-0006xZ-NH for 26629@debbugs.gnu.org; Fri, 13 May 2022 12:18:21 -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=jR84RYZGRyT/STcqAHgebvYkDADbtVgSXIPRat65sWM=; b=YQ/s9hEa9ShdR5FyXeN4/DIIQo fJvzgsQUBWTEb78FSjIcru+oNiToFAVrcYuvlLyJMVWiVRMgm43jep9hqsdY9ChZ0rFEnktfTd9/a Rv3TPqqQLscRSdlQMavKpHn+bl1QCYxLsPXTDUxYq+sTOjEc8c1+vmlnWFi8Cp1NLoiQ=; Original-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 1npXzW-0002QB-0S; Fri, 13 May 2022 18:18:12 +0200 X-Now-Playing: New Order's _Power, Corruption & Lies_: "The Village" In-Reply-To: <874lxepytq.fsf@smtp.1und1.de> (Tobias Zawada's message of "Mon, 24 Apr 2017 00:02:25 +0200") X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Original-Sender: "bug-gnu-emacs" Xref: news.gmane.io gmane.emacs.bugs:232175 Archived-At: Tobias Zawada writes: > The function copy-tree copies recursively but not structure preserving. > If two cars or cdrs link to the same sub-list in the original data > they point to two separate sub-lists in the copy. [...] > About the code: Traversing of the original graph and construction of the new graph are > stack-based as it is standard. There is an additional hash-map that maps > the already traversed old nodes to the newly created ones. If some old > node is already in the hash-map we do not create a new one in the copied > graph but use the mapped one from the hash map. (I'm going through old bug reports that unfortunately weren't resolved at the time.) I haven't looked closely at the code, but this is functionality that I vaguely remember having been requested before, and I don't think Emacs has it yet? (But I may be wrong about that.) I've added Stefan to the CCs; perhaps he has some comments. This change is large enough to require a copyright assignment of the code to the FSF -- if we decide to add the code, would you be willing to sign such paperwork? -- (domestic pets only, the antidote for overdose, milk.) bloggy blog: http://lars.ingebrigtsen.no