From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mp0 ([2001:41d0:2:4a6f::]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) by ms11 with LMTPS id e+S7CNkZkF8tHgAA0tVLHw (envelope-from ) for ; Wed, 21 Oct 2020 11:22:01 +0000 Received: from aspmx1.migadu.com ([2001:41d0:2:4a6f::]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) by mp0 with LMTPS id iKf5A9kZkF9UfgAA1q6Kng (envelope-from ) for ; Wed, 21 Oct 2020 11:22:01 +0000 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by aspmx1.migadu.com (Postfix) with ESMTPS id DD321940414 for ; Wed, 21 Oct 2020 11:22:00 +0000 (UTC) Received: from localhost ([::1]:45384 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kVCBr-0000xf-Bc for larch@yhetil.org; Wed, 21 Oct 2020 07:21:59 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:55528) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kVCBb-0000xW-In for guix-devel@gnu.org; Wed, 21 Oct 2020 07:21:43 -0400 Received: from hera.aquilenet.fr ([185.233.100.1]:53128) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kVCBZ-0004QM-Ey; Wed, 21 Oct 2020 07:21:43 -0400 Received: from localhost (localhost [127.0.0.1]) by hera.aquilenet.fr (Postfix) with ESMTP id 7C527538; Wed, 21 Oct 2020 13:21:37 +0200 (CEST) X-Virus-Scanned: Debian amavisd-new at aquilenet.fr Received: from hera.aquilenet.fr ([127.0.0.1]) by localhost (hera.aquilenet.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id SMlEAflaaS9G; Wed, 21 Oct 2020 13:21:36 +0200 (CEST) Received: from jurong (p200300dd571a0800695415b3b7c52c04.dip0.t-ipconnect.de [IPv6:2003:dd:571a:800:6954:15b3:b7c5:2c04]) by hera.aquilenet.fr (Postfix) with ESMTPSA id 3B375536; Wed, 21 Oct 2020 13:21:36 +0200 (CEST) Date: Wed, 21 Oct 2020 13:21:34 +0200 From: Andreas Enge To: Ludovic =?iso-8859-15?Q?Court=E8s?= Subject: Re: Using #true and #false everywhere? Message-ID: <20201021112134.GA4681@jurong> References: <875z7a78ww.fsf@gnu.org> <87a6wm5mv5.fsf@gmail.com> <874kmub8e1.fsf@nckx> <20201020095712.GA6805@jurong> <87pn5b7vcj.fsf@gnu.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <87pn5b7vcj.fsf@gnu.org> Received-SPF: neutral client-ip=185.233.100.1; envelope-from=andreas@enge.fr; helo=hera.aquilenet.fr X-detected-operating-system: by eggs.gnu.org: First seen = 2020/10/21 07:21:37 X-ACL-Warn: Detected OS = Linux 3.11 and newer [fuzzy] X-Spam_score_int: -10 X-Spam_score: -1.1 X-Spam_bar: - X-Spam_report: (-1.1 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_PASS=-0.001, SPF_NEUTRAL=0.779, URI_DOTEDU=0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: guix-devel@gnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: "Development of GNU Guix and the GNU System distribution." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: guix-devel@gnu.org Errors-To: guix-devel-bounces+larch=yhetil.org@gnu.org Sender: "Guix-devel" X-Scanner: scn0 Authentication-Results: aspmx1.migadu.com; dkim=none; dmarc=none; spf=pass (aspmx1.migadu.com: domain of guix-devel-bounces@gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=guix-devel-bounces@gnu.org X-Spam-Score: 0.49 X-TUID: B1hoeDjCaEdI On Wed, Oct 21, 2020 at 11:59:40AM +0200, Ludovic Courtès wrote: > What material are you referring to? SICP & co.? I simply used my favourite search engine with something such as scheme language boolean In my case the first link is to the racket manual: https://docs.racket-lang.org/reference/booleans.html Or this: https://courses.cs.washington.edu/courses/cse341/02sp/scheme/basics.html Or the Wikipedia entry: https://en.wikipedia.org/wiki/Scheme_%28programming_language%29 Any kind of search quickly reveals that booleans in Scheme are coded using #t and #f; whereas to find #true and #false, my impression is that one already needs to know that these are possibilities. I find their use more confusing than helpful. Now if we drop the #t from phases as discussed in the present thread, that would be even better. I have never been convinced by phases that always return #t and never #f; what is the point of a return value if it is not really checked? Andreas