From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Tomas Hlavaty Newsgroups: gmane.emacs.devel Subject: Re: sqlite3 Date: Sun, 19 Dec 2021 00:31:31 +0100 Message-ID: <87czlt4hik.fsf@logand.com> References: <87tufmjyai.fsf@gnus.org> <87lf0nr2b4.fsf@gnus.org> <87fsqvp5ae.fsf@gnus.org> <87bl1jp51y.fsf@gnus.org> <187323C2-81D0-47B6-96C8-3D721EF7C003@mit.edu> <8735mvp454.fsf@gnus.org> <87ilvn1xur.fsf@gnus.org> <87fsqqxsr9.fsf@gnus.org> <679ECACB-C458-4C9E-B26A-72E8D81E0A24@mit.edu> <8FA7417E-7C56-42A0-8533-DDB604965EBA@mit.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="7656"; mail-complaints-to="usenet@ciao.gmane.io" Cc: "larsi@gnus.org" , "rms@gnu.org" , "emacs-devel@gnu.org" To: Qiantan Hong , LdBeth Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Sun Dec 19 00:32:22 2021 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 1myjBd-0001r4-Dj for ged-emacs-devel@m.gmane-mx.org; Sun, 19 Dec 2021 00:32:21 +0100 Original-Received: from localhost ([::1]:39668 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1myjBc-00031q-0H for ged-emacs-devel@m.gmane-mx.org; Sat, 18 Dec 2021 18:32:20 -0500 Original-Received: from eggs.gnu.org ([209.51.188.92]:46812) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1myjB1-0002BO-Ps for emacs-devel@gnu.org; Sat, 18 Dec 2021 18:31:43 -0500 Original-Received: from logand.com ([37.48.87.44]:38568) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1myjB0-0003AG-2Z; Sat, 18 Dec 2021 18:31:43 -0500 Original-Received: by logand.com (Postfix, from userid 1001) id CD95419EC6A; Sun, 19 Dec 2021 00:31:33 +0100 (CET) X-Mailer: emacs 27.2 (via feedmail 11-beta-1 I) In-Reply-To: <8FA7417E-7C56-42A0-8533-DDB604965EBA@mit.edu> Received-SPF: pass client-ip=37.48.87.44; envelope-from=tom@logand.com; helo=logand.com X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.29 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:282343 Archived-At: On Sat 18 Dec 2021 at 09:06, Qiantan Hong wrote: > The feature of hash-consing is exactly not preserving EQness, > or, under hash-consing EQ and EQUAL degenerate to the same thing > (Aka, intensional and extensional identity degenerates), effectively > removing the concept of EQ and object identity from the language all=20 > together. It is the other way round: hash-consing "reduces" EQUAL to EQ. It does not remove the concept of identity. > In layman=E2=80=99s term: even if two objects=E2=80=99 value look the sam= e, they may > or may not be the same object. > The difference become apparent when > you poke one, and the other may or may not change. That is a consequence of having more than one definitions of same-ness. > Therefore I conclude that maybe preserving EQness in persistent store > does not make that much sense (otherwise why it can only be preserved > partially?). It could preserve EQness if every object, where EQness has to be preserved, was also stored under different key. Or there would have to be a way to reference objects stored inside the structure saved under different key. (Some kind of extended syntax for print-circle labels.)