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 20:12:32 -0700 (PDT) Message-ID: <8e35551d-6979-4474-ae84-72d75e4c8705@default> References: <87fu3vdjjk.fsf@tcd.ie> <87bmcqhhsf.fsf@tcd.ie> <951fa1f9-7e9f-4870-a377-930b91a44e05@default> <070f3619-eb6f-4615-8454-488825b27dcf@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 1528168279 23260 195.159.176.226 (5 Jun 2018 03:11:19 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Tue, 5 Jun 2018 03:11:19 +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 05:11:15 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 1fQ2NO-0005vF-LZ for ged-emacs-devel@m.gmane.org; Tue, 05 Jun 2018 05:11:14 +0200 Original-Received: from localhost ([::1]:43036 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fQ2PU-0006Ge-2q for ged-emacs-devel@m.gmane.org; Mon, 04 Jun 2018 23:13:24 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:41677) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fQ2Ou-0006GK-Lv for emacs-devel@gnu.org; Mon, 04 Jun 2018 23:12:49 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fQ2Or-0007Wt-IO for emacs-devel@gnu.org; Mon, 04 Jun 2018 23:12:48 -0400 Original-Received: from aserp2130.oracle.com ([141.146.126.79]:45142) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fQ2Or-0007WE-5B for emacs-devel@gnu.org; Mon, 04 Jun 2018 23:12:45 -0400 Original-Received: from pps.filterd (aserp2130.oracle.com [127.0.0.1]) by aserp2130.oracle.com (8.16.0.22/8.16.0.22) with SMTP id w553AuOu160279; Tue, 5 Jun 2018 03:12:35 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=mZs+HLf6d91mDb0lRedUu+sW4dcpbVjwnqiqx92WXaQ=; b=TzSTRbgFER0cvyzdOSbgQld3O1HRpdXyT/FpJIqmX4ppBWuxszM9WI59EVkqpcjNchDS R0dZxYVS7E7l2L41MAHNoXcMPhJwIc7Zu/ebg3ZwI//lZFBPV9QMTdIsDxUFEULfDpAf 3YyKVCGvokYDV3qFYl5rJCcQ/YeIS7y4L0qdf3fALVHqHrbHPuNnJB2LZWScwxCTaF9T Z5sGKwoQVkiL+Zg41S9Sge0seSaaMYRkImcqU33YoIPo/y46kmzyZBoS9xJ32b5usOzb qMSfi66JDw+lEwYaYd312Ye4Rf+qXbqaiAdOgLpUxLdKnbj0XVw9x1yhG3hwHZ1Z6Eek 9A== Original-Received: from aserv0021.oracle.com (aserv0021.oracle.com [141.146.126.233]) by aserp2130.oracle.com with ESMTP id 2jbvynx2ym-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 05 Jun 2018 03:12:35 +0000 Original-Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by aserv0021.oracle.com (8.14.4/8.14.4) with ESMTP id w553CYZZ026641 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 5 Jun 2018 03:12:35 GMT Original-Received: from abhmp0003.oracle.com (abhmp0003.oracle.com [141.146.116.9]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id w553CYgI004059; Tue, 5 Jun 2018 03:12:34 GMT In-Reply-To: <070f3619-eb6f-4615-8454-488825b27dcf@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=476 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1805220000 definitions=main-1806050038 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [generic] [fuzzy] X-Received-From: 141.146.126.79 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:226022 Archived-At: > > (null (cdr (last xs))), which is > > (and list (nthcdr (1- (safe-length xs)) xs))). >=20 > 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". >=20 > (null (cdr (last #1=3D'(2 3 #1#)))) =3D t I should have said that _some_ circular lists are "true lists". (null (cdr (last #1=3D'(2 3 #1# . 5)))) =3D nil