From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Drew Adams Newsgroups: gmane.emacs.devel Subject: RE: Predicate for true lists Date: Mon, 4 Jun 2018 20:08:11 -0700 (PDT) Message-ID: <070f3619-eb6f-4615-8454-488825b27dcf@default> References: <87fu3vdjjk.fsf@tcd.ie> <87bmcqhhsf.fsf@tcd.ie> <951fa1f9-7e9f-4870-a377-930b91a44e05@default> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Trace: blaine.gmane.org 1528168018 6575 195.159.176.226 (5 Jun 2018 03:06:58 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Tue, 5 Jun 2018 03:06:58 +0000 (UTC) To: Paul Eggert , "Basil L. Contovounesios" , emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Tue Jun 05 05:06:54 2018 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1fQ2JC-0001cf-2c for ged-emacs-devel@m.gmane.org; Tue, 05 Jun 2018 05:06:54 +0200 Original-Received: from localhost ([::1]:42930 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fQ2LI-0004j2-Up for ged-emacs-devel@m.gmane.org; Mon, 04 Jun 2018 23:09:04 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:39374) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fQ2Ki-0004iv-Cc for emacs-devel@gnu.org; Mon, 04 Jun 2018 23:08:29 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fQ2Kf-0004A2-5o for emacs-devel@gnu.org; Mon, 04 Jun 2018 23:08:28 -0400 Original-Received: from userp2130.oracle.com ([156.151.31.86]:52330) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fQ2Ke-00049O-Rb for emacs-devel@gnu.org; Mon, 04 Jun 2018 23:08:25 -0400 Original-Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.22/8.16.0.22) with SMTP id w5531mAW021827; Tue, 5 Jun 2018 03:08:15 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=mime-version : message-id : date : from : sender : to : subject : references : in-reply-to : content-type : content-transfer-encoding; s=corp-2017-10-26; bh=/nQ/xQbcKJXC5sZAY9d46MSKip2VI78c0y+MyIlOluQ=; b=CaCpsJMg4GFRB6/6tgmU1LqXfL1pfRhehgQi6TFehyf0eU+SBYiK+zaABYM6iN0nIkWS bSLluTOiwBqpwoibrLgzXy05FPNLIdl/OZLcN+L+Q//uV2+QA+auXP7wjxqd4tt6rmuN WTkF+PkDJPv0fKHu6Rp515i40wpRnVDr+fp3pvFVsjTgjx9ALNYBc7mzfll6Ag4Pr+vb Y4r3f0q89YBNXRTIwUlYHtsHaHqy8x2I4SBXiLEbJwxmrqMyA9geXKweQTIWs+UHlHZv Ch/4dAJkIvKea/58yM93YpvbZhg6TSb6Mcm2hgKBsdvoCjZntTsgXqeW7G8lMmCQsV2W BA== Original-Received: from userv0021.oracle.com (userv0021.oracle.com [156.151.31.71]) by userp2130.oracle.com with ESMTP id 2jbvyp6283-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 05 Jun 2018 03:08:15 +0000 Original-Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by userv0021.oracle.com (8.14.4/8.14.4) with ESMTP id w5538E8L026351 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 5 Jun 2018 03:08:15 GMT Original-Received: from abhmp0003.oracle.com (abhmp0003.oracle.com [141.146.116.9]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id w5538EvC009657; Tue, 5 Jun 2018 03:08:14 GMT In-Reply-To: <951fa1f9-7e9f-4870-a377-930b91a44e05@default> X-Priority: 3 X-Mailer: Oracle Beehive Extensions for Outlook 2.0.1.9.1 (1003210) [OL 16.0.4690.0 (x86)] X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=8914 signatures=668702 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=482 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1805220000 definitions=main-1806050036 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [generic] [fuzzy] X-Received-From: 156.151.31.86 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.21 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.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.org gmane.emacs.devel:226021 Archived-At: > (null (cdr (last xs))), which is > (and list (nthcdr (1- (safe-length xs)) xs))). Forgot to mention that by the manual's definition of "true list", and by this code for it, a circular list _is_ a true list. Dunno whether that was the intention of the OP's "true list". (null (cdr (last #1=3D'(2 3 #1#)))) =3D t