From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Eric Abrahamsen Newsgroups: gmane.emacs.help Subject: Re: Suppress user-prompting when calling commands in programs Date: Sat, 14 Jun 2014 11:47:56 +0800 Message-ID: <87r42sjgnn.fsf@ericabrahamsen.net> References: <87r42skjd8.fsf@gmail.com> <877g4k7ux4.fsf@geodiff-mac3.ulb.ac.be> <878up0kfcv.fsf@gmail.com> <5b284aa3-068d-461d-a95b-52cd97ba292a@default> <874mzokvwr.fsf@ericabrahamsen.net> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1402717498 4952 80.91.229.3 (14 Jun 2014 03:44:58 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sat, 14 Jun 2014 03:44:58 +0000 (UTC) To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Sat Jun 14 05:44:51 2014 Return-path: Envelope-to: geh-help-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1Wvetf-0006Bi-5a for geh-help-gnu-emacs@m.gmane.org; Sat, 14 Jun 2014 05:44:51 +0200 Original-Received: from localhost ([::1]:34069 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Wvete-0002Gr-LA for geh-help-gnu-emacs@m.gmane.org; Fri, 13 Jun 2014 23:44:50 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:46386) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WvetP-0002Gm-Tf for help-gnu-emacs@gnu.org; Fri, 13 Jun 2014 23:44:41 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WvetG-0000U9-RU for help-gnu-emacs@gnu.org; Fri, 13 Jun 2014 23:44:35 -0400 Original-Received: from plane.gmane.org ([80.91.229.3]:50897) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WvetG-0000Te-Kj for help-gnu-emacs@gnu.org; Fri, 13 Jun 2014 23:44:26 -0400 Original-Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1WvetF-0005x5-Af for help-gnu-emacs@gnu.org; Sat, 14 Jun 2014 05:44:25 +0200 Original-Received: from 114.248.8.189 ([114.248.8.189]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sat, 14 Jun 2014 05:44:25 +0200 Original-Received: from eric by 114.248.8.189 with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sat, 14 Jun 2014 05:44:25 +0200 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 30 Original-X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: 114.248.8.189 User-Agent: Gnus/5.130012 (Ma Gnus v0.12) Emacs/24.4.50 (gnu/linux) Cancel-Lock: sha1:Hmy9vfLYhq1cP8FE+qjT/FRRTuQ= X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 80.91.229.3 X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.14 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-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.help:98235 Archived-At: Drew Adams writes: >> > What's wrong with them pushing the read into the interactive spec? >> > >> > (defun foo (&optional arg bar) >> > (interactive (list current-prefix-arg >> > (org-icompleting-read ...)))) >> > ...) >> >> A quick side-question: Everyone here is using &optional for the prefix >> arg name. > > I used &optional because that is what was used in the original `foo'. > Presumably there is existing code that uses `foo' and expects that > signature, e.g., tries to evaluate `(foo)'. > >> I have several functions lying around that use the "P" >> interactive spec but don't specify arg as &optional, and seem to work >> fine. My understanding is that, if there is no prefix arg, arg will >> simply be nil, as it should be. > > Correct. > >> Apart from style/code clarity, are there other reasons for specifying >> &optional? > > See above. Use &optional if you want to be able to call the function > without passing that argument. Ah, of course -- sort of the inverse of the OP's question. Thanks!