From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.help Subject: Re: Manually parsing char-tables Date: Sun, 20 Feb 2022 14:50:54 +0200 Message-ID: <835yp9ya4x.fsf@gnu.org> References: <20220220110926.25c675be@JRWUBU2> Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="29442"; mail-complaints-to="usenet@ciao.gmane.io" To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Sun Feb 20 13:53:56 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 1nLlit-0007SZ-QA for geh-help-gnu-emacs@m.gmane-mx.org; Sun, 20 Feb 2022 13:53:55 +0100 Original-Received: from localhost ([::1]:33312 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nLlis-0004RE-Ki for geh-help-gnu-emacs@m.gmane-mx.org; Sun, 20 Feb 2022 07:53:54 -0500 Original-Received: from eggs.gnu.org ([209.51.188.92]:56868) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nLlfy-0002wZ-3K for help-gnu-emacs@gnu.org; Sun, 20 Feb 2022 07:50:54 -0500 Original-Received: from [2001:470:142:3::e] (port=55302 helo=fencepost.gnu.org) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nLlfx-0004cp-OF for help-gnu-emacs@gnu.org; Sun, 20 Feb 2022 07:50:53 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gnu.org; s=fencepost-gnu-org; h=References:Subject:In-Reply-To:To:From:Date: mime-version; bh=ePo/uiTM2BKRNDXl/f8iBt6eGzKex70t6aDk9RUp9+w=; b=lNIYzVIeBoKa E7SzW7VgDMuBiwghsMDnnxSt1HSwj3Z4pblaUfjMBMZxyOSTrZV80FkznDBKdqj4tI1sY7DW+wWmU CVDlwmlrsI7DY3IAyvcVTFvMocOkUzQ6nJXIBw4pT6ETNlF12oR/BiuhZIX8oxdLzRscYVYRKRewK hdbA5MFBirFz4B20ySSQh2wb3x+MCZ82LbMyIDYQl/AbB32wELCeLrLaGVgO+aiyk14AyN6zlG95c KmtY5reiasU3wztpETe+RAtLKAFB1eOrSrSTqxlDJwGS014c3bMjAL4kcu3CxuPlThTgX2OJZnEYH oPTdivNCONwgjBLic+YFlA==; Original-Received: from [87.69.77.57] (port=4088 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nLlfx-0006Ls-8G for help-gnu-emacs@gnu.org; Sun, 20 Feb 2022 07:50:53 -0500 In-Reply-To: <20220220110926.25c675be@JRWUBU2> (message from Richard Wordingham on Sun, 20 Feb 2022 11:09:26 +0000) 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:136052 Archived-At: > Date: Sun, 20 Feb 2022 11:09:26 +0000 > From: Richard Wordingham > > I am trying to understand how Arabic script rendering works in Emacs > 28.0.90, as it seems to be using a different mechanism to that used for > Indic or European scripts. (There seems to be more to it than just the > asymmetries between right-to-left and left-to-right.) To that end, I > am trying to understand the contents of the variable > composition-function-table. I think it is easier to just look at how the Arabic part of this table is populated. See lisp/language/misc-lang.el starting from line 105. > #^^[3 1152 nil nil nil #1# #1# #1# #1# #1# #1# #1# nil nil nil > nil nil nil nil nil nil nil nil nil nil nil nil nil nil nil nil > nil nil nil nil nil nil nil nil nil nil nil nil nil nil nil nil > nil nil nil nil nil nil nil nil nil nil nil nil nil nil nil nil > nil nil nil nil nil nil nil nil nil nil nil nil nil nil nil nil > nil nil nil nil nil nil nil nil nil nil nil nil nil nil nil nil > nil nil nil nil nil nil nil nil nil nil nil nil nil nil nil nil > nil nil nil nil nil nil nil nil nil nil nil nil nil nil nil nil > nil nil nil] > > (I've converted lines to paragraphs and abbreviated leading white > space.) > > I'm guessing that #1# is a macro invocation; when I invoke (print > composition-function-table), I get something similar, but with #1# > expanded and the '#1=' in the apparent macro definition omitted. #1# is a backreference to the value indicated by #1=. > Where is this syntax explained? I've looked in the elisp manual, but > not found it, though I may simply have failed to guess where such a > description was. See the node "Circular Objects" there. (Btw, 28.0.90 is not the latest pretest of Emacs 28, there's 28.0.91.)