From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Drew Adams Newsgroups: gmane.emacs.help Subject: RE: Rationale behind conversion of a nil prefix arg to numeric 1 Date: Sun, 4 Sep 2016 17:52:06 -0700 (PDT) Message-ID: References: <<87y437c0qg.fsf@bertrandrussell.Speedport_W_723V_1_40_000> <83oa43d9r8.fsf@gnu.org>> <<87d1kjjmys.fsf@bertrandrussell.Speedport_W_723V_1_40_000>> 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 1473036778 13989 195.159.176.226 (5 Sep 2016 00:52:58 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Mon, 5 Sep 2016 00:52:58 +0000 (UTC) To: "Florian v. Savigny" , help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Mon Sep 05 02:52:53 2016 Return-path: Envelope-to: geh-help-gnu-emacs@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 1bgi9c-0002wU-24 for geh-help-gnu-emacs@m.gmane.org; Mon, 05 Sep 2016 02:52:52 +0200 Original-Received: from localhost ([::1]:51583 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bgi9Z-0007fK-G2 for geh-help-gnu-emacs@m.gmane.org; Sun, 04 Sep 2016 20:52:49 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:56601) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bgi9A-0007f4-3o for help-gnu-emacs@gnu.org; Sun, 04 Sep 2016 20:52:25 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bgi95-0007Jm-5D for help-gnu-emacs@gnu.org; Sun, 04 Sep 2016 20:52:23 -0400 Original-Received: from userp1040.oracle.com ([156.151.31.81]:33367) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bgi94-0007J9-Rv for help-gnu-emacs@gnu.org; Sun, 04 Sep 2016 20:52:19 -0400 Original-Received: from aserv0021.oracle.com (aserv0021.oracle.com [141.146.126.233]) by userp1040.oracle.com (Sentrion-MTA-4.3.2/Sentrion-MTA-4.3.2) with ESMTP id u850q9bJ028515 (version=TLSv1 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Mon, 5 Sep 2016 00:52:11 GMT Original-Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by aserv0021.oracle.com (8.13.8/8.13.8) with ESMTP id u850q9uc025909 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Mon, 5 Sep 2016 00:52:09 GMT Original-Received: from abhmp0017.oracle.com (abhmp0017.oracle.com [141.146.116.23]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id u850q791024830; Mon, 5 Sep 2016 00:52:07 GMT In-Reply-To: <<87d1kjjmys.fsf@bertrandrussell.Speedport_W_723V_1_40_000>> X-Priority: 3 X-Mailer: Oracle Beehive Extensions for Outlook 2.0.1.9 (901082) [OL 12.0.6753.5000 (x86)] X-Source-IP: aserv0021.oracle.com [141.146.126.233] X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.4.x-2.6.x [generic] X-Received-From: 156.151.31.81 X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Original-Sender: "help-gnu-emacs" Xref: news.gmane.org gmane.emacs.help:111255 Archived-At: > > Yes. Most commands use the argument as a repeat count, so having it > > default to one makes perfect sense. >=20 > Ahh! You mean, like, C-u 80 >=20 > conveniently draws a line across the screen. Yes, that makes it > understandable indeed. Sounds like the prefix argument was more or ^ numeric > less conceived as a repeat count. Yes. It's a feature. There are several forms a raw prefix argument can take, and one `prefix-numeric-value' of it, whatever the form. The latter is called the numeric prefix argument. A command can test the numeric value (an integer) and do different things, depending on the value. A command can also test the raw prefix argument: test for its presence (non-nil) and even test for its specific non-nil form. See the Emacs manual, node `Arguments' http://www.gnu.org/software/emacs/manual/html_node/emacs/Arguments.html And see the Elisp manual, nodes: * `Prefix Command Arguments' http://www.gnu.org/software/emacs/manual/html_node/elisp/Prefix-Command-Arg= uments.html * `Interactive Codes' (`p' and `P') http://www.gnu.org/software/emacs/manual/html_node/elisp/Interactive-Codes.= html