From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Mark H Weaver Newsgroups: gmane.lisp.guile.user Subject: Re: A value for "nothing" Date: Tue, 28 Aug 2018 13:15:35 -0400 Message-ID: <87pny2h0p4.fsf@netris.org> References: <21036238.c6yQEfjfIL@aleksandar-ixtreme-m5740> <87sh30vqmm.fsf@netris.org> <20180827080415.GB10407@tuxteam.de> <87wosbsh5m.fsf@netris.org> <87sh2zsfle.fsf@netris.org> <31c7a870-aaf2-3f0e-2ef4-be4dc783a842@gmail.com> <87va7vyo2q.fsf@netris.org> <87h8jeijr2.fsf@netris.org> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: blaine.gmane.org 1535476549 2021 195.159.176.226 (28 Aug 2018 17:15:49 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Tue, 28 Aug 2018 17:15:49 +0000 (UTC) User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) Cc: guile-user@gnu.org, Matt Wette To: John Cowan Original-X-From: guile-user-bounces+guile-user=m.gmane.org@gnu.org Tue Aug 28 19:15:45 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 1fuhaj-0000Ox-5K for guile-user@m.gmane.org; Tue, 28 Aug 2018 19:15:45 +0200 Original-Received: from localhost ([::1]:39149 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fuhcp-0002B5-48 for guile-user@m.gmane.org; Tue, 28 Aug 2018 13:17:55 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:43067) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fuhcG-000260-78 for guile-user@gnu.org; Tue, 28 Aug 2018 13:17:20 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fuhc9-0003zr-Bx for guile-user@gnu.org; Tue, 28 Aug 2018 13:17:18 -0400 Original-Received: from world.peace.net ([64.112.178.59]:52386) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fuhc8-0003u0-2v for guile-user@gnu.org; Tue, 28 Aug 2018 13:17:13 -0400 Original-Received: from mhw by world.peace.net with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1fuhc6-0004e0-EL; Tue, 28 Aug 2018 13:17:10 -0400 In-Reply-To: (John Cowan's message of "Tue, 28 Aug 2018 12:12:34 -0400") X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 64.112.178.59 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:14808 Archived-At: John Cowan writes: > On Tue, Aug 28, 2018 at 11:40 AM Mark H Weaver wrote: > > That's the phrase used in R7RS-small, which fails to define it, as you > noted, but that shortcoming is limited to R7RS. > > The relevant sentences in R5RS and R7RS are identical: " If > yields a false value and no is specified, then the result > of the expression is unspecified." Likewise, the paragraph from 1.3.2 > you quote below is identical in both standards. So either they both > define it or they both don't. > > In R6RS, section 11.4.3 (Conditionals) provides this example: > > Unlike Wil Clinger, and apparently you, I don't believe that examples > in specs are normative. Alright, well, the formal denotational semantics makes it 100% unambiguous, as I noted in my previous email. Mark