From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: David Kastrup Newsgroups: gmane.lisp.guile.devel Subject: Re: when and unless Date: Tue, 06 Dec 2011 17:42:23 +0100 Organization: Organization?!? Message-ID: <877h29k5xs.fsf@fencepost.gnu.org> References: <878vsjd2fh.fsf@pobox.com> <87r50ircng.fsf@pobox.com> <4EDDC8B1.3000509@gentoo.org> <87mxb6kkzx.fsf@fencepost.gnu.org> <877h29oeeq.fsf@pobox.com> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: dough.gmane.org 1323189771 1139 80.91.229.12 (6 Dec 2011 16:42:51 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Tue, 6 Dec 2011 16:42:51 +0000 (UTC) To: guile-devel@gnu.org Original-X-From: guile-devel-bounces+guile-devel=m.gmane.org@gnu.org Tue Dec 06 17:42:48 2011 Return-path: Envelope-to: guile-devel@m.gmane.org Original-Received: from lists.gnu.org ([140.186.70.17]) by lo.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1RXy6S-0005Ge-4D for guile-devel@m.gmane.org; Tue, 06 Dec 2011 17:42:48 +0100 Original-Received: from localhost ([::1]:41870 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RXy6R-0003Tg-JL for guile-devel@m.gmane.org; Tue, 06 Dec 2011 11:42:47 -0500 Original-Received: from eggs.gnu.org ([140.186.70.92]:51340) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RXy6M-0003SB-Qq for guile-devel@gnu.org; Tue, 06 Dec 2011 11:42:45 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RXy6J-0000VD-6s for guile-devel@gnu.org; Tue, 06 Dec 2011 11:42:42 -0500 Original-Received: from lo.gmane.org ([80.91.229.12]:44663) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RXy6I-0000V9-Qh for guile-devel@gnu.org; Tue, 06 Dec 2011 11:42:39 -0500 Original-Received: from list by lo.gmane.org with local (Exim 4.69) (envelope-from ) id 1RXy6F-0005CM-W7 for guile-devel@gnu.org; Tue, 06 Dec 2011 17:42:35 +0100 Original-Received: from p508ed485.dip.t-dialin.net ([80.142.212.133]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Tue, 06 Dec 2011 17:42:35 +0100 Original-Received: from dak by p508ed485.dip.t-dialin.net with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Tue, 06 Dec 2011 17:42:35 +0100 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 27 Original-X-Complaints-To: usenet@dough.gmane.org X-Gmane-NNTP-Posting-Host: p508ed485.dip.t-dialin.net X-Face: 2FEFf>]>q>2iw=B6, xrUubRI>pR&Ml9=ao@P@i)L:\urd*t9M~y1^:+Y]'C0~{mAl`oQuAl \!3KEIp?*w`|bL5qr,H)LFO6Q=qx~iH4DN; i"; /yuIsqbLLCh/!U#X[S~(5eZ41to5f%E@'ELIi$t^ Vc\LWP@J5p^rst0+('>Er0=^1{]M9!p?&:\z]|;&=NP3AhB!B_bi^]Pfkw User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.0.90 (gnu/linux) Cancel-Lock: sha1:/vEVriti5liuzdebONOlUKe9p3M= X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6 (newer, 3) X-Received-From: 80.91.229.12 X-BeenThere: guile-devel@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "Developers list for Guile, the GNU extensibility library" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: guile-devel-bounces+guile-devel=m.gmane.org@gnu.org Original-Sender: guile-devel-bounces+guile-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.lisp.guile.devel:12991 Archived-At: Andy Wingo writes: > On Tue 06 Dec 2011 12:17, David Kastrup writes: > >> I've actually wondered if it would not make sense to return >> *unspecified* in the case of the plain else-less if even if the >> condition is true, namely when you write (if #t #t). > > I have wondered this too. > >> There is probably code relying on this to be #t, but frankly, this >> appears like a recipe for breakage. > > Yeah. A first (and probably worthwhile) step would be to warn if such > a statement is processed for value. Well, is it being processed for value if what I do with the value is calling unspecified? on it in order to find out whether I should warn about a function returning a value when it shouldn't? I am working on a language where returning values in certain contexts might at one point of time might lead to the values being used. So I need to implement warnings to that effect in order to find out calls _not_ returning *unspecified*... -- David Kastrup