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: Mon, 21 Jun 2021 01:04:12 +0200 Message-ID: <87eecwf89f.fsf@zoho.eu> References: <20210617074843.GD16310@tuxteam.de> <87r1gy3f70.fsf@zoho.eu> <20210619065703.GB29866@tuxteam.de> <87fsxdzgl9.fsf@zoho.eu> <87im28gvsx.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="38606"; 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: sha1:0BtzIi33HBZWHgYO07GIF889PVg= Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Mon Jun 21 01:04:56 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 1lv6Uo-0009kO-EJ for geh-help-gnu-emacs@m.gmane-mx.org; Mon, 21 Jun 2021 01:04:54 +0200 Original-Received: from localhost ([::1]:50556 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lv6Un-0004ZJ-Gl for geh-help-gnu-emacs@m.gmane-mx.org; Sun, 20 Jun 2021 19:04:53 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:52934) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lv6UL-0004ZA-4T for help-gnu-emacs@gnu.org; Sun, 20 Jun 2021 19:04:25 -0400 Original-Received: from ciao.gmane.io ([116.202.254.214]:34384) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lv6UJ-0000fo-22 for help-gnu-emacs@gnu.org; Sun, 20 Jun 2021 19:04:24 -0400 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1lv6UH-00096L-CI for help-gnu-emacs@gnu.org; Mon, 21 Jun 2021 01:04:21 +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:131122 Archived-At: Stefan Monnier via Users list for the GNU Emacs text editor wrote: >> might as well be >> >> (nconc (list >> '("\\.bal\\'" . balance-mode) >> '("\\.grm\\'" . sml-mode) >> '("\\.lu\\'" . lua-mode) >> '("\\.nqp\\'" . perl-mode) >> '("\\.php\\'" . html-mode) >> '("\\.pic\\'" . nroff-mode) >> '("\\.pl\\'" . prolog-mode) >> '("\\.sed\\'" . conf-mode) >> '("\\.service\\'" . conf-mode) >> '("\\.tex\\'" . latex-mode) >> '("\\.xr\\'" . conf-xdefaults-mode) >> '("*" . text-mode) ) >> auto-mode-alist) > > Here `nconc` is a safe replace for `append` because indeed > the first arg is a list you just constructed by `list` so > you know for sure it's not shared with anything else. Right. > But the second above code is just an expensive no-op because > your `nconc` will modify its first argument and not its > second Right! > Here's another way you could write the code: > > (setq auto-mode-alist > `(("\\.bal\\'" . balance-mode) > ("\\.grm\\'" . sml-mode) > ("\\.lu\\'" . lua-mode) > ("\\.nqp\\'" . perl-mode) > ("\\.php\\'" . html-mode) > ("\\.pic\\'" . nroff-mode) > ("\\.pl\\'" . prolog-mode) > ("\\.sed\\'" . conf-mode) > ("\\.service\\'" . conf-mode) > ("\\.tex\\'" . latex-mode) > ("\\.xr\\'" . conf-xdefaults-mode) > ("*" . text-mode) > ,@auto-mode-alist)) Hm, isn't that the coolest one by far? -- underground experts united https://dataswamp.org/~incal