From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Emanuel Berg Newsgroups: gmane.emacs.help Subject: Re: [External] : Re: new `pcase-let' syntax Date: Sat, 26 Nov 2022 17:01:51 +0100 Message-ID: <87bkotiu1c.fsf@dataswamp.org> References: <87o7syezkm.fsf@dataswamp.org> <87cz9c2mvr.fsf@posteo.net> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="8770"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) To: help-gnu-emacs@gnu.org Cancel-Lock: sha1:JWSROPvjqIJacBQMYOIk1ScFBE0= Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Sat Nov 26 22:10:41 2022 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 1oz2Rc-00028o-Ko for geh-help-gnu-emacs@m.gmane-mx.org; Sat, 26 Nov 2022 22:10:40 +0100 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oz2R2-0002SJ-O0; Sat, 26 Nov 2022 16:10:04 -0500 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oyxcy-0003po-PH for help-gnu-emacs@gnu.org; Sat, 26 Nov 2022 11:02:04 -0500 Original-Received: from ciao.gmane.io ([116.202.254.214]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oyxcx-0004mT-0v for help-gnu-emacs@gnu.org; Sat, 26 Nov 2022 11:02:04 -0500 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1oyxcu-0007yq-As for help-gnu-emacs@gnu.org; Sat, 26 Nov 2022 17:02:00 +0100 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: -15 X-Spam_score: -1.6 X-Spam_bar: - X-Spam_report: (-1.6 / 5.0 requ) BAYES_00=-1.9, HEADER_FROM_DIFFERENT_DOMAINS=0.25, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-Mailman-Approved-At: Sat, 26 Nov 2022 16:10:03 -0500 X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.29 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-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.help:141185 Archived-At: Drew Adams wrote: >>> (pcase-let ((`(,up ,down) >>> (if button >>> `(,#'backward-button ,#'forward-button) >>> `(,#'previous-line ,#'forward-line)))) ...) >> >> [...] I also get the feeling this is a hack for the sake of >> a hack. Is it really that much better than the "classical" >> >> (let ((up #'previous-line) (down #'forward-line)) >> (when button (setq up #'backward-button down #'forward-button))...) > > It gives you more opportunities to use your `,', ``', and > `)' keys? Okay, so how do you do this the classical way then? (pcase-let*((`(,sail ,ho) (if t '(1 2) '(3 4))) (msg (format "%s is %s" sail ho)) ) msg) Also, it's better than `let' and `setq' because if you make a typo setq creates a global variable, a bug that silently enters your code. Obviously if you gonna do typos all day ever day that's gonna be a problem even with pcase-let LOL -- underground experts united https://dataswamp.org/~incal