From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Eric Abrahamsen Newsgroups: gmane.emacs.help Subject: Re: How do I pass a variable defined in a wrapping let, to a lambda? Date: Fri, 11 Mar 2022 15:48:23 -0800 Message-ID: <87k0d03vaw.fsf@ericabrahamsen.net> References: Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="24721"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/29.0.50 (gnu/linux) To: help-gnu-emacs@gnu.org Cancel-Lock: sha1:tlOfCWMrAqueXBUFxI7x3QXg4yk= Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Sat Mar 12 01:31:46 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 1nSpfd-0006Ip-SG for geh-help-gnu-emacs@m.gmane-mx.org; Sat, 12 Mar 2022 01:31:45 +0100 Original-Received: from localhost ([::1]:48618 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nSpfc-0007VW-RZ for geh-help-gnu-emacs@m.gmane-mx.org; Fri, 11 Mar 2022 19:31:44 -0500 Original-Received: from eggs.gnu.org ([209.51.188.92]:46282) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nSozq-0004F8-C8 for help-gnu-emacs@gnu.org; Fri, 11 Mar 2022 18:48:34 -0500 Original-Received: from ciao.gmane.io ([116.202.254.214]:35272) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nSozo-0005QO-VS for help-gnu-emacs@gnu.org; Fri, 11 Mar 2022 18:48:34 -0500 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1nSozn-0006Lg-6B for help-gnu-emacs@gnu.org; Sat, 12 Mar 2022 00:48:31 +0100 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, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=no autolearn_force=no X-Spam_action: no action X-Mailman-Approved-At: Fri, 11 Mar 2022 19:30:26 -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" Xref: news.gmane.io gmane.emacs.help:136463 Archived-At: Steinar Bang writes: >> I have been trying to write a restclient.el[1] result function that can be >> used to save the body of a GET result to a file[2]. >> >> My first attempt didn't work[3]. >> >> I tried to look at an existing result function that actually worked[4], >> and I finally figured it out: the final form of that function is a >> lambda! >> >> So it was probably that lambda that was run to create the result? >> >> I rewrote my example code to this[5]. >> >> But it still didn't work. And the reason it didn't work is that >> filename didn't have a value set. >> >> If I replace the filename variable with a text constant[6], then the >> function works. >> >> But as far as I can tell, the function in[4] uses variables defined in >> the wrapping (let) in the lambda...? >> >> So why is that working but my filename failing? > They've got a lexical-binding cookie at the top of the file, but you > don't! :) Oh, maybe I'm wrong. I just tested some code in two different elisp buffers, one with lexical-binding -> t and one with it nil, and it worked in both cases. Darn -- I thought I understood lexical-binding. (defun steinars-test (file) (let ((fname (expand-file-name file))) (lambda () (message "file is %s" fname)))) (setq payload (steinars-test "~/.emacs.d/init.el")) (funcall payload)