From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from kankan.nagaokaut.ac.jp (kankan.nagaokaut.ac.jp [133.44.2.24]) by blade.nagaokaut.ac.jp (8.9.3+3.2W/8.9.3/Debian 8.9.3-21) with ESMTP id NAA02496; Thu, 25 Jul 2002 13:22:47 +0900 Received: from tonton.nagaokaut.ac.jp (tonton [133.44.2.115]) by kankan.nagaokaut.ac.jp (8.11.3/8.11.3) with ESMTP id g6P4Mp130828; Thu, 25 Jul 2002 13:22:51 +0900 (JST) (envelope-from ruby-core-admin@ruby-lang.org) Received: (from root@localhost) by tonton.nagaokaut.ac.jp (8.11.3/8.11.3) id g6P4Mpf24033; Thu, 25 Jul 2002 13:22:51 +0900 (JST) (envelope-from ruby-core-admin@ruby-lang.org) Received: from voscc.nagaokaut.ac.jp (voscc.nagaokaut.ac.jp [133.44.1.100]) by tonton.nagaokaut.ac.jp (8.11.3/8.11.3av) with ESMTP id g6P4Mn524026; Thu, 25 Jul 2002 13:22:49 +0900 (JST) (envelope-from ruby-core-admin@ruby-lang.org) Received: from helium.ruby-lang.org (helium.ruby-lang.org [210.251.121.214]) by voscc.nagaokaut.ac.jp (8.12.5/8.12.5) with ESMTP id g6P4Mma3074980; Thu, 25 Jul 2002 13:22:48 +0900 (JST) (envelope-from ruby-core-admin@ruby-lang.org) Received: from helium.ruby-lang.org (localhost [127.0.0.1]) by helium.ruby-lang.org (Postfix) with ESMTP id 4C93B15BE; Thu, 25 Jul 2002 13:22:48 +0900 (JST) Received: from picachu.netlab.jp (picachu2.netlab.jp [210.163.138.98]) by helium.ruby-lang.org (Postfix) with ESMTP id C635F152F for ; Thu, 25 Jul 2002 13:22:47 +0900 (JST) Received: from ev.(none) (dhcp187.priv.netlab.jp [192.168.1.187]) by picachu.netlab.jp (Postfix) with SMTP id 92C742D0B7 for ; Thu, 25 Jul 2002 13:22:47 +0900 (JST) Received: (nullmailer pid 15239 invoked by uid 1000); Thu, 25 Jul 2002 00:32:34 -0000 Date: Thu, 25 Jul 2002 13:22:48 +0900 Posted: Thu, 25 Jul 2002 09:32:34 +0900 From: matz@ruby-lang.org (Yukihiro Matsumoto) Reply-To: ruby-core@ruby-lang.org Subject: unifying nil and false (Re: [PATCH] object.c ruby.h) To: ruby-core@ruby-lang.org Message-Id: <1027557154.122024.15237.nullmailer@picachu.netlab.jp> In-Reply-To: Dave Thomas's message of "Thu, 25 Jul 2002 05:05:46 +0900" References: <200207241950.g6OJoOMJ004731@miso.k.notwork.org> X-ML-Name: ruby-core X-Mail-Count: 00242 X-MLServer: fml [fml 3.0pl#17]; post only (only members can post) X-ML-Info: If you have a question, send e-mail with the body "help" (without quotes) to the address ruby-core-ctl@ruby-lang.org; help= X-Mailer: cmail 2.61.1 on GNU Emacs 21.2.1 / Mule 5.0 (SAKAKI) User-Agent: SEMI/1.14.3 (Ushinoya) FLIM/1.14.3 (=?ISO-8859-4?Q?Unebigory?= =?ISO-8859-4?Q?=F2mae?=) APEL/10.3 Emacs/21.2 (i386-debian-linux-gnu) MULE/5.0 (SAKAKI) Mime-Version: 1.0 (generated by SEMI 1.14.3 - "Ushinoya") Content-Type: text/plain; charset=US-ASCII Precedence: bulk X-Virus-Scanned: by AMaViS perl-10 Hi, In message "Re: [PATCH] object.c ruby.h (fwd)" on 02/07/25, Dave Thomas writes: |At the same time, I'm wondering if it would be possible to unify nil |and false, so that they were both the same object? "nil" and "false" are treated differently everywhere. Unifying them will cause serious compatibility problem. For example, Thread#status returns false for threads terminated normally, nil for threads terminated with exceptions. See ri Thread#status. Also I've heard they're used for three state logic (true - false - undefined). So it's not easy to unify them. matz.