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: Making a function than can only be used interactively Date: Mon, 04 Jul 2022 17:18:22 -0400 Message-ID: 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="18003"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/29.0.50 (gnu/linux) Cc: tsdh@gnu.org, help-gnu-emacs@gnu.org To: Christopher Dimech Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Mon Jul 04 23:19:18 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 1o8TTS-0004SY-3l for geh-help-gnu-emacs@m.gmane-mx.org; Mon, 04 Jul 2022 23:19:18 +0200 Original-Received: from localhost ([::1]:58840 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1o8TTQ-0004HY-Gq for geh-help-gnu-emacs@m.gmane-mx.org; Mon, 04 Jul 2022 17:19:16 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:56546) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1o8TSf-0004HB-Sw for help-gnu-emacs@gnu.org; Mon, 04 Jul 2022 17:18:29 -0400 Original-Received: from mailscanner.iro.umontreal.ca ([132.204.25.50]:31521) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1o8TSd-0003TW-0a; Mon, 04 Jul 2022 17:18:28 -0400 Original-Received: from pmg3.iro.umontreal.ca (localhost [127.0.0.1]) by pmg3.iro.umontreal.ca (Proxmox) with ESMTP id 04A93442433; Mon, 4 Jul 2022 17:18:25 -0400 (EDT) Original-Received: from mail01.iro.umontreal.ca (unknown [172.31.2.1]) by pmg3.iro.umontreal.ca (Proxmox) with ESMTP id A6425442430; Mon, 4 Jul 2022 17:18:23 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=iro.umontreal.ca; s=mail; t=1656969503; bh=GRnf1Tt0Re67lZHY0EGZVFMiBLDsikxAi5JG+aDWmSI=; h=From:To:Cc:Subject:References:Date:In-Reply-To:From; b=XcUsJedx2WOKLRqhA1dIU+iX2DRyyCrb7VUoQ/BeV0N1PQO8jrZXlpQ3PJxIpqIeB evUZqmMvbq5S1UVeNBZ7MqgImV0Un1LlmSxE43B+327QW6y06oLO/hemfPJjXHsGLr akyv5cEHLQlNFQBzPQnWAPfa9jNxeVW/QQPZdrYcWfoVFgFdsdt/rM0uNhd1kh0hk8 H0zDxfDBElSmAmNHGJ0d3RDsvNOJXz5qN3ipUSXSjpnZ+8SS+VHFWvkr05E3kG3Foe 9+sqmZkGkSG+M7bkilcfGXJTP4hyLOwrhy7yzQzCwcTCXKFIQ/4UYSEb5HiAEcD6vh YJ1ZrxWBEUVtA== Original-Received: from alfajor (unknown [45.72.196.165]) by mail01.iro.umontreal.ca (Postfix) with ESMTPSA id 6D42F120173; Mon, 4 Jul 2022 17:18:23 -0400 (EDT) In-Reply-To: (Christopher Dimech's message of "Mon, 4 Jul 2022 22:46:18 +0200") Received-SPF: pass client-ip=132.204.25.50; envelope-from=monnier@iro.umontreal.ca; helo=mailscanner.iro.umontreal.ca X-Spam_score_int: -42 X-Spam_score: -4.3 X-Spam_bar: ---- X-Spam_report: (-4.3 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action 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:138301 Archived-At: > Another debate is that although one can declare a non-interactive function, > and an interactive function that can run non-interactively; there is no > construct that can define a purely interactive function. That's because an "interactive function" is just a normal function together with some auxiliary info to tell `call-interactive` how to call it "interactively". Internally `call-interactively` will end up calling the function via `funcall`, i.e. "non-interactively". So at a low-level, technically you just can't have a function that can be called interactively and not non-interactively. You can try and kludge it up above if you really want to (like we've seen in a few different ways), but we're back to the question: what's the benefit? > Does a function know whether it was run from lisp code or from the user in > an Emacs session? Trying to behave differently depending on who/how a function was called goes against the design principle of functions, so it tends to be kludgy and unreliable, like `called-interactively-p`. BTW, here's another way to make a function that "can't" be called non-interactively: (defun foo (a b c &optional extra) (interactive (list ... 'dont-you-dare-call-me-non-interactively)) (unless (eql extra 'dont-you-dare-call-me-non-interactively) (error "foo called non-interactively")) ...) You can make it "more robust" with something like: (defalias 'foo (let ((witness (make-symbol "dont-you-dare-call-me-non-interactively"))) (lambda (a b c &optional extra) (interactive (list ... witness)) (unless (eql extra witness) (error "foo called non-interactively")) ...))) But again: is it really worth the trouble? What is there to gain? Instead of beating the undesired callers with a stick, why not try and convince them to do something else with carrot? Stefan