From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.help Subject: Re: How to tame compiler? Date: Fri, 30 Apr 2021 23:49:40 -0400 Message-ID: References: <875z03th9b.fsf@web.de> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="29925"; 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:No2HZN7u+BEJ0C8jH90c1JfnWUE= Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Sat May 01 05:50:29 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 1lcgeD-0007hi-9V for geh-help-gnu-emacs@m.gmane-mx.org; Sat, 01 May 2021 05:50:29 +0200 Original-Received: from localhost ([::1]:42400 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lcgeC-0002V1-CF for geh-help-gnu-emacs@m.gmane-mx.org; Fri, 30 Apr 2021 23:50:28 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:34802) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lcgda-0002Ui-2r for help-gnu-emacs@gnu.org; Fri, 30 Apr 2021 23:49:50 -0400 Original-Received: from ciao.gmane.io ([116.202.254.214]:54892) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lcgdY-0007tt-GJ for help-gnu-emacs@gnu.org; Fri, 30 Apr 2021 23:49:49 -0400 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1lcgdV-0006zb-Mp for help-gnu-emacs@gnu.org; Sat, 01 May 2021 05:49:45 +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: -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-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:129247 Archived-At: Michael Heerdegen [2021-05-01 02:44:16] wrote: > Jean Louis writes: >> As I have recently implemented new function that use `eval' to expand >> various variables and these variables are not visibly used in the >> program, I would like to tame the compiler, as I get these warnings: >> >> In rcd-send-email: >> rcd-mailing.el:225:62: Warning: Unused lexical variable `unsubscribe-url' >> rcd-mailing.el:231:21: Warning: Unused lexical variable `hello-name' >> rcd-mailing.el:234:72: Warning: Unused lexical variable `unsubscribe-text' >> rcd-mailing.el:252:11: Warning: Unused lexical variable `body' >> >> What is happening here is that those variables are used but inside of >> `eval' form which is expanded dynamically when program runs. Compiler >> cannot see that. >> >> Is there a way to avoid these warnings? > > Independent from the question whether your usage of `eval' is good or > valid - there must be some real problem here: if the compiler tells that > the lexical variables are unused, their values will not be available in > you `eval' call - you would have to create dynamical bindings for that. I know I sound like a broken clock, but I think a better answer is to avoid `eval`: instead of taking expressions (that you'd pass to `eval`) arrange to receive functions (which you'd pass to `funcall` or `apply`). Then you can pass those functions the data they need (e.g. the value of things like `unsubscribe-text`). Stefan