From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Miles Bader Newsgroups: gmane.emacs.devel Subject: Re: Documentation for car and cdr Date: Thu, 26 Jan 2006 10:54:52 +0900 Message-ID: References: Reply-To: Miles Bader NNTP-Posting-Host: main.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: sea.gmane.org 1138240520 8406 80.91.229.2 (26 Jan 2006 01:55:20 GMT) X-Complaints-To: usenet@sea.gmane.org NNTP-Posting-Date: Thu, 26 Jan 2006 01:55:20 +0000 (UTC) Cc: Bill Atkins , emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Thu Jan 26 02:55:18 2006 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([199.232.76.165]) by ciao.gmane.org with esmtp (Exim 4.43) id 1F1wLv-0005CQ-Pe for ged-emacs-devel@m.gmane.org; Thu, 26 Jan 2006 02:55:12 +0100 Original-Received: from localhost ([127.0.0.1] helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1F1wOg-0004qg-Jd for ged-emacs-devel@m.gmane.org; Wed, 25 Jan 2006 20:58:02 -0500 Original-Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1F1wOX-0004qL-FG for emacs-devel@gnu.org; Wed, 25 Jan 2006 20:57:53 -0500 Original-Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1F1wOV-0004q9-Qz for emacs-devel@gnu.org; Wed, 25 Jan 2006 20:57:53 -0500 Original-Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1F1wOV-0004q6-NV for emacs-devel@gnu.org; Wed, 25 Jan 2006 20:57:51 -0500 Original-Received: from [203.180.232.82] (helo=mgate02.necel.com) by monty-python.gnu.org with esmtp (Exim 4.52) id 1F1wLw-0001kQ-4j; Wed, 25 Jan 2006 20:55:12 -0500 Original-Received: from relay21.aps.necel.com (relay21 [10.29.19.50]) by mgate02.necel.com (8.13.1/8.13.1) with ESMTP id k0PLp4V8014696; Thu, 26 Jan 2006 10:54:52 +0900 (JST) Original-Received: from relay31.aps.necel.com ([10.29.19.20] [10.29.19.20]) by relay21.aps.necel.com with ESMTP; Thu, 26 Jan 2006 10:54:52 +0900 Original-Received: from dhapc248.dev.necel.com ([10.114.97.235] [10.114.97.235]) by relay31.aps.necel.com with ESMTP; Thu, 26 Jan 2006 10:54:52 +0900 Original-Received: by dhapc248.dev.necel.com (Postfix, from userid 31295) id 56A0F41B; Thu, 26 Jan 2006 10:54:52 +0900 (JST) Original-To: Alan Mackenzie System-Type: i686-pc-linux-gnu Blat: Foop In-Reply-To: (Alan Mackenzie's message of "Wed, 25 Jan 2006 21:41:26 +0000 (GMT)") Original-Lines: 25 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:49565 Archived-At: Alan Mackenzie writes: > Others have asserted that "cdr returns the cdr" is a coherent > description of cdr. They are thus implying that "cdr" is semantically > different from "cdr", otherwise that description would be circular and > vacuous. Er, well they _are_ different in that sentence -- the first "cdr" is a function, the second "cdr" is the name of part of a data-structure. I guess this thread has become a bit overblown (this is a minor issue!), but I agree that in some cases it might nice to describe the "list meaning" of such functions as an addendum, to help beginners. E.g. Return the cdr of the cons-cell CONS. If CONS is nil, return nil. Signal an error if CONS is not nil and not a cons cell. See also `cdr-safe'. When CONS is interpreted as a list, cdr returns the list tail (the list with the first member removed). -miles -- Run away! Run away!