From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED.blaine.gmane.org!not-for-mail From: Paul Eggert Newsgroups: gmane.emacs.devel Subject: Re: Comparing symbol-with-position using eq Date: Fri, 5 Apr 2019 17:50:20 -0500 Message-ID: References: <20190402112537.GA6212@ACM> <20190402202412.GA25792@ACM> <4a2df4442b4acf2eb2dabd3c2c4227c5.squirrel@dancol.org> <20190402210013.GD25792@ACM> <87bm1l6oq5.fsf@gmail.com> <20190405082652.GA4208@ACM> <87ftqwcrgo.fsf_-_@gmail.com> <20190405182106.GC4208@ACM> <47d94f87b51706205f4fe7ce4d938d53.squirrel@dancol.org> <20190405215450.GD4208@ACM> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Injection-Info: blaine.gmane.org; posting-host="blaine.gmane.org:195.159.176.226"; logging-data="60665"; mail-complaints-to="usenet@blaine.gmane.org" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 Cc: Alex , emacs-devel@gnu.org To: Alan Mackenzie , Daniel Colascione Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Sat Apr 06 01:05:52 2019 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([209.51.188.17]) by blaine.gmane.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:256) (Exim 4.89) (envelope-from ) id 1hCXuA-000Fax-Ov for ged-emacs-devel@m.gmane.org; Sat, 06 Apr 2019 01:05:50 +0200 Original-Received: from localhost ([127.0.0.1]:47930 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hCXu9-0008L1-Nr for ged-emacs-devel@m.gmane.org; Fri, 05 Apr 2019 19:05:49 -0400 Original-Received: from eggs.gnu.org ([209.51.188.92]:45954) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hCXsJ-0007eP-NY for emacs-devel@gnu.org; Fri, 05 Apr 2019 19:03:56 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hCXfj-0001U4-UN for emacs-devel@gnu.org; Fri, 05 Apr 2019 18:50:57 -0400 Original-Received: from zimbra.cs.ucla.edu ([131.179.128.68]:41026) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hCXff-0001CG-DB for emacs-devel@gnu.org; Fri, 05 Apr 2019 18:50:52 -0400 Original-Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id 5A1C2161603; Fri, 5 Apr 2019 15:50:46 -0700 (PDT) Original-Received: from zimbra.cs.ucla.edu ([127.0.0.1]) by localhost (zimbra.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id bDzj04FG_FpC; Fri, 5 Apr 2019 15:50:45 -0700 (PDT) Original-Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id 5FB5C161626; Fri, 5 Apr 2019 15:50:45 -0700 (PDT) X-Virus-Scanned: amavisd-new at zimbra.cs.ucla.edu Original-Received: from zimbra.cs.ucla.edu ([127.0.0.1]) by localhost (zimbra.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id yiRG-vN1rrmN; Fri, 5 Apr 2019 15:50:45 -0700 (PDT) Original-Received: from [172.20.8.153] (unknown [12.197.214.2]) by zimbra.cs.ucla.edu (Postfix) with ESMTPSA id 0FDE9161516; Fri, 5 Apr 2019 15:50:45 -0700 (PDT) In-Reply-To: <20190405215450.GD4208@ACM> Content-Language: en-US X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 131.179.128.68 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.org gmane.emacs.devel:235014 Archived-At: On 4/5/19 4:54 PM, Alan Mackenzie wrote: > I've been thinking that for the time (nearly 3 years) that I've been > trying to fix this bug. Is this how compilers for other Lisp systems are > written? It seems horribly easy to compile as Emacs does, by taking the > (read) starting form and gradually transforming it as a Lisp form. Sure, it's standard for Lisp compilers to use a representation that is somewhat more complicated than the original. This kind of practice goes back a long way. For example, the Multics MACLISP compiler, although it didn't do a full AST, systematically used a different representation (i.e., not simple symbols) for variables, a representation that let the compiler issue more-precise diagnostics. See Bernard Greenberg's tutorial . Although this sort of thing does complicate the compiler, that's typically better than complicating 'eq'. 'eq' is supposed to be verrry simple and straightforward.