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: `when-let' (was: Re: My read-buffer-function doesn't work when called by switch-to-buffer) Date: Sat, 11 Mar 2023 21:40:12 +0100 Message-ID: <87pm9fkonn.fsf_-_@dataswamp.org> References: <875yb8nvvk.fsf@gnu.org> <87y1o486wo.fsf@web.de> <87fsabslcj.fsf@gnu.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="8807"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) To: help-gnu-emacs@gnu.org Cancel-Lock: sha1:10ZJNyYE1kYSQmuDyIWfxnoh+Fk= Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Mon Mar 13 08:36:49 2023 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 1pbcjh-00025Y-B9 for geh-help-gnu-emacs@m.gmane-mx.org; Mon, 13 Mar 2023 08:36:49 +0100 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pbcje-0000ho-NS; Mon, 13 Mar 2023 03:36:46 -0400 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 1pb60u-0005Qj-16 for help-gnu-emacs@gnu.org; Sat, 11 Mar 2023 15:40:24 -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 1pb60s-0005Mc-Bu for help-gnu-emacs@gnu.org; Sat, 11 Mar 2023 15:40:23 -0500 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1pb60q-00010L-7T for help-gnu-emacs@gnu.org; Sat, 11 Mar 2023 21:40:20 +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: Mon, 13 Mar 2023 03:36:46 -0400 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:143009 Archived-At: Tassilo Horn wrote: > (when-let ((result (completing-read [...] )))) `when-let' is so cool! I didn't use it once. But I used `let' 457 times, and `when' 161 times. So what about this (setq initial-scratch-message nil) (when-let ((buf (get-buffer "*scratch*"))) (kill-buffer buf) ) ? There is also `if-let'. But no "unless-let". Yeah, like if all of these are nil, then do something with them ... There are also the sequential/non-"parallel"/self-refering `when-let*' and `if-let*'! Actually, there are and-let* cl--loop-let if-let[*] macroexp-let* macroexp-let2[*] map-let named-let pcase-let[*] rx-let seq-let when-let[*] while-let and more! I have 6 `pcase-let' and 1 `pcase-let*' and - now - 1 `when-let'. Yeah - it's not a lot :( -- underground experts united https://dataswamp.org/~incal