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: new `pcase-let' syntax hotter than TikTok girls? Date: Wed, 23 Nov 2022 11:26:49 +0100 Message-ID: <87o7syezkm.fsf@dataswamp.org> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="39922"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Cc: Andreas , Jovelou , Ladbon , Pebben , Per To: help-gnu-emacs@gnu.org Cancel-Lock: sha1:dH3gTqr2rsbZgXOSaPRP5H48EcE= Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Thu Nov 24 14:28:57 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 1oyCHh-000ADy-4Q for geh-help-gnu-emacs@m.gmane-mx.org; Thu, 24 Nov 2022 14:28:57 +0100 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oyCHZ-0000mW-Vs; Thu, 24 Nov 2022 08:28:50 -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 1oxmy6-0004Xi-7b for help-gnu-emacs@gnu.org; Wed, 23 Nov 2022 05:27:02 -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 1oxmy3-00069d-JY for help-gnu-emacs@gnu.org; Wed, 23 Nov 2022 05:27:01 -0500 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1oxmy0-0005ve-IF for help-gnu-emacs@gnu.org; Wed, 23 Nov 2022 11:26:56 +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: -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-Mailman-Approved-At: Thu, 24 Nov 2022 08:28:44 -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:141140 Archived-At: Check out this syntax with `pcase-let'! :O (pcase-let ((`(,up ,down) (if button `(,#'backward-button ,#'forward-button) `(,#'previous-line ,#'forward-line) ))) ... ) Advantage: A single test (here, `if') but without the bulky and ugly combo with `let*' and `car'/`cadr' ... Here is an example how it can be used, and actually is used already [1] (defun set-vertical-keys (kmap &optional button np tab) (pcase-let ((`(,up ,down) (if button `(,#'backward-button ,#'forward-button) `(,#'previous-line ,#'forward-line) ))) (define-key kmap "i" up) (define-key kmap "k" down) (when np (define-key kmap "p" up) (define-key kmap "n" down) ) (when tab (define-key kmap [backtab] up) (define-key kmap "\t" down) ))) and then for example [2] (let ((kmap Buffer-menu-mode-map)) (set-vertical-keys kmap nil nil t) ;; ... ) Too sexy for its shirt! [1] https://dataswamp.org/~incal/emacs-init/scroll.el [2] https://dataswamp.org/~incal/emacs-init/buffer-menu.el -- underground experts united https://dataswamp.org/~incal