From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: carlmarcos--- via Users list for the GNU Emacs text editor Newsgroups: gmane.emacs.help Subject: Re: Making a function than can only be used interactively Date: Fri, 8 Jul 2022 14:18:16 +0200 (CEST) Message-ID: References: <875yk8ehp8.fsf@dataswamp.org> <87bku0ce1f.fsf@dataswamp.org> Reply-To: carlmarcos@tutanota.com Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="17392"; mail-complaints-to="usenet@ciao.gmane.io" Cc: Yuri Khan , help-gnu-emacs To: carlmarcos@tutanota.com Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Fri Jul 08 14:19:52 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 1o9mxb-0004Mk-Bs for geh-help-gnu-emacs@m.gmane-mx.org; Fri, 08 Jul 2022 14:19:51 +0200 Original-Received: from localhost ([::1]:48130 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1o9mxa-0004rK-1b for geh-help-gnu-emacs@m.gmane-mx.org; Fri, 08 Jul 2022 08:19:50 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:46344) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1o9mw9-0003l6-Fk for help-gnu-emacs@gnu.org; Fri, 08 Jul 2022 08:18:21 -0400 Original-Received: from w1.tutanota.de ([81.3.6.162]:44310) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1o9mw6-0005HD-BI for help-gnu-emacs@gnu.org; Fri, 08 Jul 2022 08:18:20 -0400 Original-Received: from w3.tutanota.de (unknown [192.168.1.164]) by w1.tutanota.de (Postfix) with ESMTP id CFE9FFBF926; Fri, 8 Jul 2022 12:18:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1657282696; s=s1; d=tutanota.com; h=From:From:To:To:Subject:Subject:Content-Description:Content-ID:Content-Type:Content-Type:Content-Transfer-Encoding:Cc:Cc:Date:Date:In-Reply-To:In-Reply-To:MIME-Version:MIME-Version:Message-ID:Message-ID:Reply-To:References:References:Sender; bh=yEi6UlPDYj0RJ3OmPmq4W4sw5HTUu6MM8M0AnF3cq4c=; b=bs7RdDd/2TgiPdE2XHo8EBnRYMoCkrYb7Iaj6HlwDAsctXu/lrUn7WcU5e5oYiRW FQH1ca8EkX3zNSQEiFI0hUHoRvEcKgI+JADVcpwOYU7vJQ3CyCJzpCVn+PS1rVd4F9G edRn4OjH9h0rWveIc3oaiHxsdQKMuDESW/3jqwN8zHGkIQ4mb69CJIvAV+iweOSejme s9HKZl7fmezzgyLAtxbsWm4UbXd1x/6ZNYU2DRh2cuDBzJzeK8Og86pcqtDO1Vh91LC ib+2RhK+DIGGZ3Q1rwxTUs0l+nyW38xZqa/9vgJRe9kZ/Zqi48S54KvyV6SQrLuuljY 0yCUU7s+4w== In-Reply-To: Received-SPF: pass client-ip=81.3.6.162; envelope-from=carlmarcos@tutanota.com; helo=w1.tutanota.de X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, HTML_MESSAGE=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-Content-Filtered-By: Mailman/MimeDel 2.1.29 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:138378 Archived-At: Jul 8, 2022, 12:06 by help-gnu-emacs@gnu.org: > Jul 8, 2022, 06:55 by yuri.v.khan@gmail.com: > >> On Fri, 8 Jul 2022 at 13:31, Emanuel Berg wrote: >> >>> > It does not matter for interactive use. [...] =E2=80=98&optional=E2= =80=99 >>> > comes into play if you use this function non-interactively, >>> > from Lisp >>> >>> No, it matters. One example how it matters is that optional >>> arguments defaults to nil. >>> >> >> You=E2=80=99re right, with an interactive specification that evaluates t= o a >> list it matters, because the list you return may or may not have as >> many arguments as the function takes. >> >> My point was that in the specific case of a three-argument function >> and a three-item string-valued interactive specification, &optional >> does not matter for interactive use. >> What should one be concerned with most when deciding when and what argument= s are defined as optional.=C2=A0 When in non-interactive mode, or in interact= ive mode? >>> Check out this file and in particular example 4 which doesn't >>> make sense to me? >>> >>> ;; DWIM example 1, from Lisp ignore region if set >>> ;; example 2, use the region if available from Lisp as well >>> >>> (defun test-dwim (&optional beg end) >>> (interactive (when (use-region-p) >>> (list (region-beginning) (region-end)) )) >>> >> >> Here you have two cases. If the region is active, you produce a >> two-element list, otherwise, a 0-element list. The function signature >> allows 0..2 arguments, so it works in either case. >> >>> ;; example 3, one call to `use-region-p' is enough >>> >>> (defun test-dwim-3 (re &optional beg end) >>> (interactive `(,(read-regexp "re: ") >>> ,@(when (use-region-p) >>> (list (region-beginning) (region-end)) ))) >>> >> >> Mostly same, except you build a list of 3 or 1 elements, and the >> function accepts 1..3 arguments. >> >>> ;; example 4, let's do that with the `interactive' spec >>> ;; string. but without `use-region-p' it doesn't reset after >>> ;; I clear the region, or that's what I thought happened >>> ;; anyway :) so this doesn't work as intended, which >>> ;; `test-dwim-3' does, supposedly the worse one. >>> >>> (defun test-dwim-4 (re &optional beg end) >>> (interactive "sre: \nr") >>> >> >> Here you use a string interactive spec which always produces 3 >> elements. In non-interactive use, it will work if called as >> (test-dwim-4 "^foo$"), (test-dwim-4 "^foo$" 42), or (test-dwim-4 >> "^foo$" 42 69). >> >> As to your =E2=80=9Cclearing=E2=80=9D the region, Emacs always maintains= the point and >> mark positions, and the =E2=80=98r=E2=80=99 interactive spec code ignore= s the region >> activation flag and always passes the point and mark. (This could be >> considered a bug, but I see no good alternative behavior, except maybe >> passing two nils if the region is not active.) >> > There seems to exist total confusion on how to use the interactive clause= and how=20 > when to use mandatory or optional arguments, and how to handle them.=C2= =A0 >