From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.devel Subject: Re: Arbitrary function: find the number(s) of expected arguments Date: Sat, 19 Mar 2016 15:52:45 -0400 Message-ID: References: <56E8906C.5050405@lanl.gov> <83egb68vfy.fsf@gnu.org> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1458417193 10136 80.91.229.3 (19 Mar 2016 19:53:13 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sat, 19 Mar 2016 19:53:13 +0000 (UTC) To: emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Sat Mar 19 20:53:05 2016 Return-path: Envelope-to: ged-emacs-devel@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 1ahMvo-0003ej-8c for ged-emacs-devel@m.gmane.org; Sat, 19 Mar 2016 20:53:04 +0100 Original-Received: from localhost ([::1]:50243 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ahMvn-0004Jd-GR for ged-emacs-devel@m.gmane.org; Sat, 19 Mar 2016 15:53:03 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:39832) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ahMvj-0004JX-PE for emacs-devel@gnu.org; Sat, 19 Mar 2016 15:53:00 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ahMve-00027Z-NZ for emacs-devel@gnu.org; Sat, 19 Mar 2016 15:52:59 -0400 Original-Received: from plane.gmane.org ([80.91.229.3]:57092) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ahMve-00027B-Gy for emacs-devel@gnu.org; Sat, 19 Mar 2016 15:52:54 -0400 Original-Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1ahMvc-0003Xs-AX for emacs-devel@gnu.org; Sat, 19 Mar 2016 20:52:52 +0100 Original-Received: from 107-179-144-20.cpe.teksavvy.com ([107.179.144.20]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sat, 19 Mar 2016 20:52:52 +0100 Original-Received: from monnier by 107-179-144-20.cpe.teksavvy.com with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sat, 19 Mar 2016 20:52:52 +0100 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 15 Original-X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: 107-179-144-20.cpe.teksavvy.com User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.1.50 (gnu/linux) Cancel-Lock: sha1:ZmvbseqmlI594XsqXDmC2/yR7zw= X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 80.91.229.3 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.14 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-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:201899 Archived-At: > Patches to add func-arity to Emacs are welcome. Actually, I don't welcome them. I always resisted them, because I think that using func-arity is a bad idea. As mentioned to my reply in the corresponding thread, you're better off just making the call and catching the potential `wrong-number-of-arguments' signal. Stefan PS: Little quiz: what should be the func-arity of (lambda (&rest x) (apply #'car x))?