From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Philipp Stephani Newsgroups: gmane.emacs.help Subject: Re: Plist-put changes literal argument Date: Sat, 5 Sep 2020 17:53:52 +0200 Message-ID: References: <30E631BA-6845-43C1-AB5E-4C02C4F44780@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="blaine.gmane.org:116.202.254.214"; logging-data="27892"; mail-complaints-to="usenet@ciao.gmane.io" Cc: help-gnu-emacs To: Yuan Fu Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Sat Sep 05 17:54:28 2020 Return-path: Envelope-to: geh-help-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 1kEaWK-0007BZ-HJ for geh-help-gnu-emacs@m.gmane-mx.org; Sat, 05 Sep 2020 17:54:28 +0200 Original-Received: from localhost ([::1]:45260 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kEaWJ-0007IK-Il for geh-help-gnu-emacs@m.gmane-mx.org; Sat, 05 Sep 2020 11:54:27 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:47732) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kEaVz-0007Hn-6P for help-gnu-emacs@gnu.org; Sat, 05 Sep 2020 11:54:07 -0400 Original-Received: from mail-ot1-x32d.google.com ([2607:f8b0:4864:20::32d]:36705) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1kEaVx-00079H-Hm for help-gnu-emacs@gnu.org; Sat, 05 Sep 2020 11:54:06 -0400 Original-Received: by mail-ot1-x32d.google.com with SMTP id 109so8668676otv.3 for ; Sat, 05 Sep 2020 08:54:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=Tm0KTDaLiK6IMbDaTQqYMOxqLvrPfrUq/s+Q4r/aho8=; b=YD42jIdsnEZn1Fo2Uh2MxVzm4Sd4B0TzRxx+6BSr8IChoOTsVXJ+ulRHSA6850NE0K 1u7ABCi1WOhdtGEnqXiOCsCIB8Re4jkt5Mf9uE4JbBsTolCax50TUB5T7zSVHsz6v2ZC JdFZsPMHr6X5ZjkueqRLEWT9oPSp2zlHH+1Xx4V/Sh9iFOPfXLRKUGJJLKihUiK47qLm A5vnYRRjDgR/eOdpyh4JoqTDMiIOuIl7TlMnxPSQgC2neem7GSHrBvefKXevaO+AXeeb CLPJYjwWC41orpQEVW9hrYb1IxKESKZuN2A5St0516EmJaJmbqNupRaIoXSRrqs/9CPb mYyA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=Tm0KTDaLiK6IMbDaTQqYMOxqLvrPfrUq/s+Q4r/aho8=; b=nGnyLmZ9O9gwYMhmrnGIUkU/hUloloqAO+OzTV36LnhbbztbAsHRkuBCG/btilPycj a3C8pRLVdZdiPaVR7bS9+Xx0d3/dF0+VlelBhiFpvOnpuPo/YcLvSMza0jlrdzhlOP9k ITBhOdKFEMiOvEcTC+neCnnS8WrMVS6yywLq4xh7dV9IBGlYPlGROo7w4AYB6LdWgep8 244fUlwN3W8smAicyjtt0NQu4CXtIYMik9msytz+45zk1PypOWskyL4qF4NkRlkonS41 1BWeVcYMj6EeadMte6bdeFn6WOr9memnmjNJ1OCIh8fhWEEhfvNHyalZVU/CFOyuNHbp HrHw== X-Gm-Message-State: AOAM531plHN3NP782GES8bp8R1PaS9SZKIgH8Au3Rtk/LB3bnKYFVKDJ pdRq/SZqsNZIY+loyEYac08Eue+IlUaKdxGBq2Y= X-Google-Smtp-Source: ABdhPJzfFSysg4fTEr9xhcH1e438JN6bnh/uUA5d8au+Y8qWwp+9U6v64yeYwqTeJAt0Eu5/hPguhflJ+ZA8rqb61bs= X-Received: by 2002:a9d:20c1:: with SMTP id x59mr9167920ota.36.1599321243385; Sat, 05 Sep 2020 08:54:03 -0700 (PDT) In-Reply-To: Received-SPF: pass client-ip=2607:f8b0:4864:20::32d; envelope-from=p.stephani2@gmail.com; helo=mail-ot1-x32d.google.com X-detected-operating-system: by eggs.gnu.org: No matching host in p0f cache. That's all we know. X-Spam_score_int: -17 X-Spam_score: -1.8 X-Spam_bar: - X-Spam_report: (-1.8 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_ENVFROM_END_DIGIT=0.25, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Original-Sender: "help-gnu-emacs" Xref: news.gmane.io gmane.emacs.help:123976 Archived-At: Am Do., 3. Sept. 2020 um 01:59 Uhr schrieb Yuan Fu : > > > > > On Sep 2, 2020, at 7:55 PM, Yuan Fu wrote: > > > > I found plist-put changes the literal argument I pass to a function: > > > > (defun test () > > (test-2 '(:a b))) > > > > (defun test-2 (form) > > (print form) > > (plist-put form :a 'c) > > nil) > > > > (progn (test) (test)) > > > > (:a b) > > > > (:a c) > > nil > > > > I thought Elisp is pass-by-copy? Is this expected? > > > > P.S., (setf (alist-get )) does the same, I guess this IS expected? > > > > Yuan > > I also tried setcar, same result. So Elisp doesn=E2=80=99t copy arguments= ? Lists (actually all values except fixnums/small integers) are always passed by reference; or, in other words, a list argument actually contains a pointer to the list, not the list itself. Copying the pointer doesn't copy the list.