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#24875: 26.0.50; In Dotted Pair Notation, the read function returns CDR if CAR is absent Date: Tue, 06 Jul 2021 19:15:09 +0200 Message-ID: <8735srqs82.fsf@gnus.org> References: <87fun7v02h.fsf@xuchunyang.me> <87zguzpiet.fsf@gnus.org> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="4932"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) Cc: Chunyang Xu , 24875@debbugs.gnu.org To: Stefan Monnier Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Tue Jul 06 19:18:55 2021 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 1m0oik-00011E-2h for geb-bug-gnu-emacs@m.gmane-mx.org; Tue, 06 Jul 2021 19:18:54 +0200 Original-Received: from localhost ([::1]:48076 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1m0oij-00005L-4z for geb-bug-gnu-emacs@m.gmane-mx.org; Tue, 06 Jul 2021 13:18:53 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:36232) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1m0ofy-0004dz-3a for bug-gnu-emacs@gnu.org; Tue, 06 Jul 2021 13:16:02 -0400 Original-Received: from debbugs.gnu.org ([209.51.188.43]:38422) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1m0ofx-0001Mf-Q8 for bug-gnu-emacs@gnu.org; Tue, 06 Jul 2021 13:16:01 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1m0ofx-0006xR-Le for bug-gnu-emacs@gnu.org; Tue, 06 Jul 2021 13:16:01 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Lars Ingebrigtsen Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Tue, 06 Jul 2021 17:16:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 24875 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: moreinfo Original-Received: via spool by 24875-submit@debbugs.gnu.org id=B24875.162559172226670 (code B ref 24875); Tue, 06 Jul 2021 17:16:01 +0000 Original-Received: (at 24875) by debbugs.gnu.org; 6 Jul 2021 17:15:22 +0000 Original-Received: from localhost ([127.0.0.1]:49962 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1m0ofK-0006w6-0d for submit@debbugs.gnu.org; Tue, 06 Jul 2021 13:15:22 -0400 Original-Received: from quimby.gnus.org ([95.216.78.240]:42724) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1m0ofI-0006vo-2U for 24875@debbugs.gnu.org; Tue, 06 Jul 2021 13:15:21 -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=NxUVYJFPbEMPTdAaPp/V77E0dytuAptoG3Fne13vgUA=; b=nHlGw17j3iL/yg/HLlUveSwOhD /+FcpXeWd3x0vNW95c7xk/joBlKWni0awvaMi7o7auhFU2rX8EGLWv30wgdH1Xj4l1EydCacPxt13 eqXRfTPJRgJWOPvNzRhhgBOelDwEz3J2YPjS8GJIv9+QcGWkBeH7HTxnN8RMp/X/19lY=; Original-Received: from cm-84.212.220.105.getinternet.no ([84.212.220.105] helo=elva) by quimby.gnus.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1m0of8-0003Ml-4u; Tue, 06 Jul 2021 19:15:12 +0200 X-Now-Playing: FKA Twigs's _Magdalene_: "Mary Magdalene" In-Reply-To: (Stefan Monnier's message of "Tue, 06 Jul 2021 12:43:58 -0400") 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:209555 Archived-At: Stefan Monnier writes: > It's the "natural" behavior if you start from > > (Ea . Ed) > > as the notation for cons cells and extend it to > > (E1 E2 E3 .. . Ed) > > such that > > (E1 {foo} . Ed) = (E1 . ({foo} . Ed)) > > because then you replace `{foo}` with the empty sequence and you get: > > (E1 . Ed) = (E1 . ( . Ed)) > > and hence > > Ed = ( . Ed) > > It's not used very often, so in theory we could potentially change it, > but I haven't seen any good alternative interpretation for it, and > I don't see the benefit of signaling an error. Ah, I see! Thanks for the explanation -- I now taken a stab at finding a place in the Lisp manual to explain this (and explaining it slightly shorter). Feel free to adjust as required. -- (domestic pets only, the antidote for overdose, milk.) bloggy blog: http://lars.ingebrigtsen.no