From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Emanuel Berg via Users list for the GNU Emacs text editor Newsgroups: gmane.emacs.help Subject: Re: [External] : Re: Appending lists Date: Wed, 16 Jun 2021 19:06:47 +0200 Message-ID: <87tulxu4bc.fsf@zoho.eu> References: <4tl1yvylvg1fxx5eefjs9mnk.1623688568572@email.android.com> <87o8c8l32h.fsf@posteo.net> <87zgvs2bup.fsf@zoho.eu> <87y2bby1kr.fsf@zoho.eu> <20210615091834.GB24886@tuxteam.de> <87im2ewr3k.fsf@zoho.eu> <20210616072819.GB17919@tuxteam.de> <87r1h1vk0q.fsf@zoho.eu> Reply-To: Emanuel Berg Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="10506"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) To: help-gnu-emacs@gnu.org Cancel-Lock: sha1:hAM2d99g1SaiX0hEZjJ+zgW26UE= Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Wed Jun 16 19:11:21 2021 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 1ltZ4T-0002Uw-0x for geh-help-gnu-emacs@m.gmane-mx.org; Wed, 16 Jun 2021 19:11:21 +0200 Original-Received: from localhost ([::1]:43536 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ltZ4S-00022R-0q for geh-help-gnu-emacs@m.gmane-mx.org; Wed, 16 Jun 2021 13:11:20 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:49500) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ltZ3J-00020b-W0 for help-gnu-emacs@gnu.org; Wed, 16 Jun 2021 13:10:18 -0400 Original-Received: from ciao.gmane.io ([116.202.254.214]:59996) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ltZ3F-00008d-FX for help-gnu-emacs@gnu.org; Wed, 16 Jun 2021 13:10:09 -0400 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1ltZ3B-0000gE-KZ for help-gnu-emacs@gnu.org; Wed, 16 Jun 2021 19:10:01 +0200 X-Injected-Via-Gmane: http://gmane.org/ Mail-Followup-To: help-gnu-emacs@gnu.org Mail-Copies-To: never Received-SPF: pass client-ip=116.202.254.214; envelope-from=geh-help-gnu-emacs@m.gmane-mx.org; helo=ciao.gmane.io X-Spam_score_int: -16 X-Spam_score: -1.7 X-Spam_bar: - X-Spam_report: (-1.7 / 5.0 requ) BAYES_00=-1.9, HEADER_FROM_DIFFERENT_DOMAINS=0.249, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no 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:130916 Archived-At: Drew Adams wrote: >> Maybe that still isn't a guarantee nreverse can't screw up >> something else just the same, unsure how to "partition" or >> isolate it if you will? > > Read your mail quickly. HTH. In general, you can use > a "destructive" function such as `nreverse' on something > that you've created, e.g. as a separate object from other > existing objects. E.g., if you _copy_ a list then you can > use `nreverse' on your copy without bothering the list > you copied. > > Depending on the kind of "destructive" operation, you might > need to make a deep copy. In all cases, if you use > a destructive operation, you should know what it does - > that's a prerequisite, unless you really enjoy surprises. "Copy", you mean to send the value as an argument? What's a "deep copy"? I have used `nconc' 7 times and `nreverse'. Still no surprises so maybe I just haven't committed to them enough. -- underground experts united https://dataswamp.org/~incal