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.bugs Subject: bug#40671: [DOC] modify literal objects Date: Fri, 1 May 2020 14:40:59 -0700 Organization: UCLA Computer Science Department Message-ID: References: <530d3597-aaaa-f019-bafa-8229d13e7248@yandex.ru> <60b88f52-c50d-c57a-9ce5-495e6157d36e@cs.ucla.edu> <0721d8c1-4fe3-335c-7dbc-171487cb648a@yandex.ru> <6d1015da-0dc1-376c-f84b-5e3ee3149213@cs.ucla.edu> <286139d2-bbe1-2d5a-bec1-f781666376f1@yandex.ru> <10b89e6f-6fa6-f855-65b6-3361a74472d3@cs.ucla.edu> <8542efe2-c4a6-1da5-2513-7ffcaa6c4ec9@yandex.ru> <293d0eab-4617-08fe-aafa-d6841a750af0@cs.ucla.edu> <4085994e-f42d-b90f-9c86-ad42689bbff2@yandex.ru> <9cfc3b63-7df6-145a-8a78-e3320b6d3861@cs.ucla.edu> <72399223-0ab5-dbe4-5027-d929450a4df0@yandex.ru> <1a2d0454-baa4-9831-0e2c-4411eda1c2fe@yandex.ru> <278a1350-8b9e-4f3b-854a-723d578129f3@default> <6cbe3c10-6d81-f2be-30d7-17096b3f3517@yandex.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Injection-Info: ciao.gmane.io; posting-host="ciao.gmane.io:159.69.161.202"; logging-data="21136"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 Cc: Michael Heerdegen , Mattias =?UTF-8?Q?Engdeg=C3=A5rd?= , ke.vigouroux@laposte.net, 40671@debbugs.gnu.org, Richard Stallman To: Dmitry Gutov , Drew Adams Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Fri May 01 23:46:10 2020 Return-path: Envelope-to: geb-bug-gnu-emacs@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 1jUdU1-0005Li-Ow for geb-bug-gnu-emacs@m.gmane-mx.org; Fri, 01 May 2020 23:46:09 +0200 Original-Received: from localhost ([::1]:47858 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jUdU0-0001Lg-Ng for geb-bug-gnu-emacs@m.gmane-mx.org; 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Fri, 1 May 2020 14:40:59 -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 9236F160079; Fri, 1 May 2020 14:40:59 -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: <6cbe3c10-6d81-f2be-30d7-17096b3f3517@yandex.ru> Content-Language: en-US X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-Received-From: 209.51.188.43 X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Original-Sender: "bug-gnu-emacs" Xref: news.gmane.io gmane.emacs.bugs:179464 Archived-At: On 4/30/20 8:13 PM, Dmitry Gutov wrote: > On 29.04.2020 04:38, Paul Eggert wrote: >> Here's a quote from CLtL2 (page 115): >> >> "it is an error to destructively modify any object that appears as a constant >> in executable code, whether within a 'quote' special form or as >> a self-evaluating form." > > As Drew pointed out (and if I understood this correctly), the above > specification leads to implementations that do raise an error when someone tried > to modify such a value. Although those implementations conform to the Common Lisp spec, that's because the spec explicitly says such behavior is undefined - which means implementations can signal an error, dump core, or do whatever else they want. See , which uses "should" in the same sense the emacs-27 elisp manual uses "should". Here's a quote: ----- When this book specifies that it "is an error" for some situation to occur, this means that: * No valid Common Lisp program should cause this situation to occur. * If this situation occurs, the effects and results are completely undefined as far as adherence to the Common Lisp specification is concerned. * No Common Lisp implementation is required to detect such an error. Of course, implementors are encouraged to provide for detection of such errors wherever reasonable. This is not to say that some particular implementation might not define the effects and results for such a situation; the point is that no program conforming to the Common Lisp specification may correctly depend on such effects or results.