From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Stefan Monnier via Users list for the GNU Emacs text editor Newsgroups: gmane.emacs.help Subject: Re: [External] : Re: Lexical vs. dynamic: small examples? Date: Sun, 15 Aug 2021 18:44:42 -0400 Message-ID: References: <4a9bddb9ec57299b3b0c@heytings.org> <87y293sdxk.fsf@zoho.eu> <87pmufs4er.fsf@zoho.eu> <87wnompmpw.fsf@zoho.eu> <87k0kmgycz.fsf@gnus.org> <87y292nya4.fsf@zoho.eu> Reply-To: Stefan Monnier Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="34994"; 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:rMmWd3NdEe169LRuli3+gaMibyI= Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Mon Aug 16 00:45:27 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 1mFOsh-0008tb-5F for geh-help-gnu-emacs@m.gmane-mx.org; Mon, 16 Aug 2021 00:45:27 +0200 Original-Received: from localhost ([::1]:47346 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mFOsf-0007bc-P6 for geh-help-gnu-emacs@m.gmane-mx.org; Sun, 15 Aug 2021 18:45:25 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:33584) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mFOs5-0007a6-RH for help-gnu-emacs@gnu.org; Sun, 15 Aug 2021 18:44:49 -0400 Original-Received: from ciao.gmane.io ([116.202.254.214]:40222) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mFOs4-0002Qr-A5 for help-gnu-emacs@gnu.org; Sun, 15 Aug 2021 18:44:49 -0400 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1mFOs2-00080b-Lv for help-gnu-emacs@gnu.org; Mon, 16 Aug 2021 00:44:46 +0200 X-Injected-Via-Gmane: http://gmane.org/ 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:132594 Archived-At: Emanuel Berg via Users list for the GNU Emacs text editor [2021-08-16 00:22:43] wrote: > Lars Ingebrigtsen wrote: >>> So the proposal/question is, instead one could have `let' >>> _always_ be lexical, and one "with-variables-as" which >>> would be what is now called "dynamic binding" with let. >> These are `lexical-let' and `dlet' (in Emacs 28). > Ha! Now you are telling... Note that `lexical-let` is an old thing of the deprecated `cl.el` library which let you have static scoping let-bindings before `lexical-binding` existed. When `lexical-binding` is not enabled it's still currently the only way I know to get a statically scoped let-binding, but when `lexical-binding` is enabled you can use: (defmacro slet (bindings &rest body) (unless lexical-binding (error "`slet' requires `lexical-binding' to be enabled")) `(funcall (lambda ,(mapcar #'car bindings) ,@body) ,@(mapcar #'cadr bindings))) instead, Stefan