From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Paul Eggert Newsgroups: gmane.emacs.devel Subject: Re: Using the GNU GMP Library for Bignums in Emacs Date: Tue, 10 Jul 2018 19:35:15 -0700 Organization: UCLA Computer Science Department Message-ID: <9ee4b3c6-9d87-a8e6-7e07-455da91c8966@cs.ucla.edu> References: <29f933ac-a6bf-8742-66a7-0a9d6d3e5a88@disroot.org> <83bmecy6fx.fsf@gnu.org> <0d3175d8-d996-651e-b221-71978bde3a65@cs.ucla.edu> <87tvpdnzgy.fsf@tromey.com> <4c2a814f-c254-29e5-39cf-11b5f2e5c9c8@cs.ucla.edu> <49d8ba62-c9a5-9203-d882-8e900b441ff3@cs.ucla.edu> <8e0320d9-e0d0-2b57-57cc-2df4399f133c@cs.ucla.edu> <87lgaio7xd.fsf@tromey.com> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable X-Trace: blaine.gmane.org 1531276404 24524 195.159.176.226 (11 Jul 2018 02:33:24 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Wed, 11 Jul 2018 02:33:24 +0000 (UTC) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 Cc: emacs-devel@gnu.org To: Tom Tromey , Stefan Monnier Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Wed Jul 11 04:33:20 2018 Return-path: Envelope-to: ged-emacs-devel@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 1fd4wS-0006ID-7W for ged-emacs-devel@m.gmane.org; Wed, 11 Jul 2018 04:33:20 +0200 Original-Received: from localhost ([::1]:51361 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fd4yZ-0006cu-D5 for ged-emacs-devel@m.gmane.org; Tue, 10 Jul 2018 22:35:31 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:34900) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fd4yS-0006b8-RU for emacs-devel@gnu.org; Tue, 10 Jul 2018 22:35:25 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fd4yO-0001oC-AY for emacs-devel@gnu.org; Tue, 10 Jul 2018 22:35:24 -0400 Original-Received: from zimbra.cs.ucla.edu ([131.179.128.68]:39000) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fd4yN-0001mi-SA for emacs-devel@gnu.org; Tue, 10 Jul 2018 22:35:20 -0400 Original-Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id 6A3C7160980; Tue, 10 Jul 2018 19:35:17 -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 1QgAv5Y1_Fwu; Tue, 10 Jul 2018 19:35:16 -0700 (PDT) Original-Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id 95E9016099B; Tue, 10 Jul 2018 19:35:16 -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 XkQluQCdDOtU; Tue, 10 Jul 2018 19:35:16 -0700 (PDT) Original-Received: from [192.168.1.9] (unknown [47.154.30.119]) by zimbra.cs.ucla.edu (Postfix) with ESMTPSA id 363FE160980; Tue, 10 Jul 2018 19:35:16 -0700 (PDT) Openpgp: preference=signencrypt Autocrypt: addr=eggert@cs.ucla.edu; prefer-encrypt=mutual; keydata= xsFNBEyAcmQBEADAAyH2xoTu7ppG5D3a8FMZEon74dCvc4+q1XA2J2tBy2pwaTqfhpxxdGA9 Jj50UJ3PD4bSUEgN8tLZ0san47l5XTAFLi2456ciSl5m8sKaHlGdt9XmAAtmXqeZVIYX/UFS 96fDzf4xhEmm/y7LbYEPQdUdxu47xA5KhTYp5bltF3WYDz1Ygd7gx07Auwp7iw7eNvnoDTAl KAl8KYDZzbDNCQGEbpY3efZIvPdeI+FWQN4W+kghy+P6au6PrIIhYraeua7XDdb2LS1en3Ss mE3QjqfRqI/A2ue8JMwsvXe/WK38Ezs6x74iTaqI3AFH6ilAhDqpMnd/msSESNFt76DiO1ZK QMr9amVPknjfPmJISqdhgB1DlEdw34sROf6V8mZw0xfqT6PKE46LcFefzs0kbg4GORf8vjG2 Sf1tk5eU8MBiyN/bZ03bKNjNYMpODDQQwuP84kYLkX2wBxxMAhBxwbDVZudzxDZJ1C2VXujC OJVxq2kljBM9ETYuUGqd75AW2LXrLw6+MuIsHFAYAgRr7+KcwDgBAfwhPBYX34nSSiHlmLC+ KaHLeCLF5ZI2vKm3HEeCTtlOg7xZEONgwzL+fdKo+D6SoC8RRxJKs8a3sVfI4t6CnrQzvJbB n6gxdgCu5i29J1QCYrCYvql2UyFPAK+do99/1jOXT4m2836j1wARAQABzSBQYXVsIEVnZ2Vy dCA8ZWdnZXJ0QGNzLnVjbGEuZWR1PsLBfgQTAQIAKAUCTIByZAIbAwUJEswDAAYLCQgHAwIG FQgCCQoLBBYCAwECH In-Reply-To: <87lgaio7xd.fsf@tromey.com> Content-Language: en-US X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [fuzzy] 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:227234 Archived-At: > I read this thread and I still don't know what a use case for this woul= d be. Yes, I'm not seeing it either. > it's simpler to explain that there are just integers. Yes, and this is a significant win. If interning bignums (so that eq works on them) is what it takes to satif= y=20 Stefan's concerns, then I'm all for interning them. The idea is to avoid=20 unnecessary distinctions between fixnums and bignums, so that Lisp progra= mmers=20 can focus on their problems rather than worry about integer representatio= n.=20 Although it's OK to have user-visible predicates fixnump and bignump for = the few=20 programmers who really need to know, I'm not seeing use cases for why the= se=20 predicates should be any more special than characterp or natnump are. >> why would someone want to specialize a method just for fixnums, as >> opposed to a method for integers? > > cl-generic has no trouble dispatching on a supertype of that returned = by > `type-of`. That's fine, but I was asking for use cases not implementation motivation= . THat=20 is, I was wondering why a Lisp programmer would want to use cl-generic th= at way.=20 Having cl-generic distinguish fixnums from bignums sounds like more a sol= ution=20 looking for a problem than a truly useful feature. >> The basic operations +, -, * etc. aren't specialized for fixnums. > > Actually, they are, but this is done by manual type-testing in the > C code, not with cl-defmethod. Yes, of course: with basic operations it's done under the hood, and Lisp=20 programmers don't need to worry about the details. This is a reasonable=20 programming style for Emacs Lisp, and it'd be a good thing if this style = were=20 used as consistently as possible, to keep things simpler.