From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: ludo@gnu.org (Ludovic =?utf-8?Q?Court=C3=A8s?=) Newsgroups: gmane.lisp.guile.user Subject: Re: A value for "nothing" Date: Mon, 27 Aug 2018 14:37:36 +0200 Message-ID: <87lg8s9e9b.fsf@gnu.org> References: <21036238.c6yQEfjfIL@aleksandar-ixtreme-m5740> <3467110.H24gZIzStD@aleksandar-ixtreme-m5740> <87ftz0vidc.fsf@netris.org> <15511073.3h7x93ioX3@aleksandar-ixtreme-m5740> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Trace: blaine.gmane.org 1535375293 4605 195.159.176.226 (27 Aug 2018 13:08:13 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Mon, 27 Aug 2018 13:08:13 +0000 (UTC) User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) To: guile-user@gnu.org Original-X-From: guile-user-bounces+guile-user=m.gmane.org@gnu.org Mon Aug 27 15:08:09 2018 Return-path: Envelope-to: guile-user@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 1fuHFY-00018b-Hh for guile-user@m.gmane.org; Mon, 27 Aug 2018 15:08:08 +0200 Original-Received: from localhost ([::1]:53160 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fuHHe-0005yw-TB for guile-user@m.gmane.org; Mon, 27 Aug 2018 09:10:18 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:40773) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fuH7D-00045p-BK for guile-user@gnu.org; Mon, 27 Aug 2018 08:59:34 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fuGmC-0005Tf-2n for guile-user@gnu.org; Mon, 27 Aug 2018 08:37:51 -0400 Original-Received: from [195.159.176.226] (port=35689 helo=blaine.gmane.org) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1fuGmB-0005Rm-Rs for guile-user@gnu.org; Mon, 27 Aug 2018 08:37:48 -0400 Original-Received: from list by blaine.gmane.org with local (Exim 4.84_2) (envelope-from ) id 1fuGjz-0004Gk-Ut for guile-user@gnu.org; Mon, 27 Aug 2018 14:35:31 +0200 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 13 Original-X-Complaints-To: usenet@blaine.gmane.org X-URL: http://www.fdn.fr/~lcourtes/ X-Revolutionary-Date: 10 Fructidor an 226 de la =?utf-8?Q?R=C3=A9volution?= X-PGP-Key-ID: 0x090B11993D9AEBB5 X-PGP-Key: http://www.fdn.fr/~lcourtes/ludovic.asc X-PGP-Fingerprint: 3CE4 6455 8A84 FDC6 9DB4 0CFB 090B 1199 3D9A EBB5 X-OS: x86_64-pc-linux-gnu Cancel-Lock: sha1:xxsbpqZFDHb5kqSB0J5ZGxzsj6Q= X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 195.159.176.226 X-BeenThere: guile-user@gnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: General Guile related discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: guile-user-bounces+guile-user=m.gmane.org@gnu.org Original-Sender: "guile-user" Xref: news.gmane.org gmane.lisp.guile.user:14783 Archived-At: Hi, I would suggesting returning zero values, using: (values) That way, if a caller wrongfully attempts to get at the return value of that procedure, it’ll get an error. Fibers does that in several places, and I think it’s a good convention as it conveys exactly what you want. Ludo’.