From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.ciao.gmane.io!not-for-mail From: Paul Eggert Newsgroups: gmane.emacs.devel Subject: =?UTF-8?Q?Re=3a_31395511=3a_=22Don=e2=80=99t_attempt_to_modify_cons?= =?UTF-8?Q?tant_strings=22?= Date: Fri, 5 Jun 2020 18:43:05 -0700 Organization: UCLA Computer Science Department Message-ID: <58642244-da07-c96d-21d5-d7d46714678d@cs.ucla.edu> References: <871rmvn7ge.fsf@gmail.com> <87lfl36abx.fsf@gmail.com> <1abe5965-b48e-6dee-1516-c5c233f09d01@cs.ucla.edu> <873679lel3.fsf@gmail.com> <87d06dje3d.fsf@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Injection-Info: ciao.gmane.io; posting-host="ciao.gmane.io:159.69.161.202"; logging-data="53097"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 Cc: Pip Cet , emacs-devel To: =?UTF-8?B?Sm/Do28gVMOhdm9yYQ==?= , Dmitry Gutov Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Sat Jun 06 03:43:41 2020 Return-path: Envelope-to: ged-emacs-devel@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1jhNs5-000Dih-8c for ged-emacs-devel@m.gmane-mx.org; Sat, 06 Jun 2020 03:43:41 +0200 Original-Received: from localhost ([::1]:39262 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jhNs4-0004rx-9z for ged-emacs-devel@m.gmane-mx.org; Fri, 05 Jun 2020 21:43:40 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:51644) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jhNrb-0004Sb-Vc for emacs-devel@gnu.org; Fri, 05 Jun 2020 21:43:12 -0400 Original-Received: from zimbra.cs.ucla.edu ([131.179.128.68]:39600) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jhNra-0004qy-HJ for emacs-devel@gnu.org; Fri, 05 Jun 2020 21:43:11 -0400 Original-Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id 66A601600D1; Fri, 5 Jun 2020 18:43:07 -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 S6MENx94GJkU; Fri, 5 Jun 2020 18:43:06 -0700 (PDT) Original-Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id A4B221600D4; Fri, 5 Jun 2020 18:43:06 -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 Bdib-QoPuzxj; Fri, 5 Jun 2020 18:43:06 -0700 (PDT) Original-Received: from [192.168.1.9] (cpe-23-242-74-103.socal.res.rr.com [23.242.74.103]) by zimbra.cs.ucla.edu (Postfix) with ESMTPSA id 6FE411600DE; Fri, 5 Jun 2020 18:43:06 -0700 (PDT) Autocrypt: addr=eggert@cs.ucla.edu; prefer-encrypt=mutual; keydata= LS0tLS1CRUdJTiBQR1AgUFVCTElDIEtFWSBCTE9DSy0tLS0tCgptUUlOQkV5QWNtUUJFQURB QXlIMnhvVHU3cHBHNUQzYThGTVpFb243NGRDdmM0K3ExWEEySjJ0QnkycHdhVHFmCmhweHhk R0E5Smo1MFVKM1BENGJTVUVnTjh0TFowc2FuNDdsNVhUQUZMaTI0NTZjaVNsNW04c0thSGxH ZHQ5WG0KQUF0bVhxZVpWSVlYL1VGUzk2ZkR6ZjR4aEVtbS95N0xiWUVQUWRVZHh1NDd4QTVL aFRZcDVibHRGM1dZRHoxWQpnZDdneDA3QXV3cDdpdzdlTnZub0RUQWxLQWw4S1lEWnpiRE5D UUdFYnBZM2VmWkl2UGRlSStGV1FONFcra2doCnkrUDZhdTZQcklJaFlyYWV1YTdYRGRiMkxT MWVuM1NzbUUzUWpxZlJxSS9BMnVlOEpNd3N2WGUvV0szOEV6czYKeDc0aVRhcUkzQUZINmls QWhEcXBNbmQvbXNTRVNORnQ3NkRpTzFaS1FNcjlhbVZQa25qZlBtSklTcWRoZ0IxRApsRWR3 MzRzUk9mNlY4bVp3MHhmcVQ2UEtFNDZMY0ZlZnpzMGtiZzRHT1JmOHZqRzJTZjF0azVlVThN Qml5Ti9iClowM2JLTmpOWU1wT0REUVF3dVA4NGtZTGtYMndCeHhNQWhCeHdiRFZadWR6eERa SjFDMlZYdWpDT0pWeHEya2wKakJNOUVUWXVVR3FkNzVBVzJMWHJMdzYrTXVJc0hGQVlBZ1Jy NytLY3dEZ0JBZndoU In-Reply-To: <87d06dje3d.fsf@gmail.com> Content-Language: en-US Received-SPF: pass client-ip=131.179.128.68; envelope-from=eggert@cs.ucla.edu; helo=zimbra.cs.ucla.edu X-detected-operating-system: by eggs.gnu.org: First seen = 2020/06/05 21:43:07 X-ACL-Warn: Detected OS = Linux 3.1-3.10 X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, SPF_PASS=-0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.23 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-mx.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.io gmane.emacs.devel:251926 Archived-At: On 6/5/20 4:19 PM, Jo=C3=A3o T=C3=A1vora wrote: > I totally agree it is > undefined behaviour to change structure of literals (quoted or > self-evaluating objects), also in Common Lisp, because compilers are > probably allowed to reuse parts of the internal structure of such > objects. But that's a far cry from having two different manifestations > of `equal` such objects _be_ the same object, but only for compiled > code. I don't understand this remark, as the idea that "compilers are allowed t= o reuse parts" necessarily implies that (eq "a" "a") can be t if the compiler dec= ides to reuse the string. Certainly in Common Lisp (eq "Foo" "Foo") might be true= or false (this specific example is called out in CLtL 6.3). Anyway, Elisp has behaved compatibly with Common Lisp for some time, and = it works well in practice. I doubt whether it'd be a good idea to try to cha= nge Elisp to require each string literal "unique", whatever that turns out to= mean.