From mboxrd@z Thu Jan 1 00:00:00 1970 Path: main.gmane.org!not-for-mail From: David.Kastrup@t-online.de (David Kastrup) Newsgroups: gmane.emacs.devel Subject: Re: invisible text and point Date: 27 May 2003 09:26:27 +0200 Sender: emacs-devel-bounces+emacs-devel=quimby.gnus.org@gnu.org Message-ID: References: <200305260437.h4Q4bbh14766@eel.dms.auburn.edu> <200305261721.h4QHLigb001231@rum.cs.yale.edu> <200305261813.h4QIDN815240@eel.dms.auburn.edu> <200305261826.h4QIQX5S001474@rum.cs.yale.edu> <200305270213.h4R2DpP15774@eel.dms.auburn.edu> Reply-To: dak@gnu.org NNTP-Posting-Host: main.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: main.gmane.org 1054020688 14968 80.91.224.249 (27 May 2003 07:31:28 GMT) X-Complaints-To: usenet@main.gmane.org NNTP-Posting-Date: Tue, 27 May 2003 07:31:28 +0000 (UTC) Cc: monnier+gnu/emacs@rum.cs.yale.edu Original-X-From: emacs-devel-bounces+emacs-devel=quimby.gnus.org@gnu.org Tue May 27 09:31:26 2003 Return-path: Original-Received: from quimby.gnus.org ([80.91.224.244]) by main.gmane.org with esmtp (Exim 3.35 #1 (Debian)) id 19KYve-0003t4-00 for ; Tue, 27 May 2003 09:31:26 +0200 Original-Received: from monty-python.gnu.org ([199.232.76.173]) by quimby.gnus.org with esmtp (Exim 3.12 #1 (Debian)) id 19KZ9F-0005yG-00 for ; Tue, 27 May 2003 09:45:29 +0200 Original-Received: from localhost ([127.0.0.1] helo=monty-python.gnu.org) by monty-python.gnu.org with esmtp (Exim 4.20) id 19KYua-0004en-Rg for emacs-devel@quimby.gnus.org; Tue, 27 May 2003 03:30:20 -0400 Original-Received: from list by monty-python.gnu.org with tmda-scanned (Exim 4.20) id 19KYtP-0003tP-Sk for emacs-devel@gnu.org; Tue, 27 May 2003 03:29:07 -0400 Original-Received: from mail by monty-python.gnu.org with spam-scanned (Exim 4.20) id 19KYrI-0003D9-5p for emacs-devel@gnu.org; Tue, 27 May 2003 03:26:56 -0400 Original-Received: from mailout03.sul.t-online.com ([194.25.134.81]) by monty-python.gnu.org with esmtp (Exim 4.20) id 19KYr9-000391-4w for emacs-devel@gnu.org; Tue, 27 May 2003 03:26:47 -0400 Original-Received: from fwd08.sul.t-online.de by mailout03.sul.t-online.com with smtp id 19KYqy-0002t3-0B; Tue, 27 May 2003 09:26:36 +0200 Original-Received: from localhost.localdomain (520018396234-0001@[62.226.12.150]) by fwd08.sul.t-online.com with esmtp id 19KYqt-0G2btgC; Tue, 27 May 2003 09:26:31 +0200 Original-Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by localhost.localdomain (8.12.8/8.12.8) with ESMTP id h4R7QTR5001892; Tue, 27 May 2003 09:26:29 +0200 Original-Received: (from dak@localhost) by localhost.localdomain (8.12.8/8.12.8/Submit) id h4R7QRLq001888; Tue, 27 May 2003 09:26:27 +0200 Original-To: Luc Teirlinck In-Reply-To: <200305270213.h4R2DpP15774@eel.dms.auburn.edu> Original-Lines: 45 User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.3.50 X-Sender: 520018396234-0001@t-dialin.net Original-cc: emacs-devel@gnu.org X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1b5 Precedence: list List-Id: Emacs development discussions. List-Help: List-Post: List-Subscribe: , List-Archive: List-Unsubscribe: , Errors-To: emacs-devel-bounces+emacs-devel=quimby.gnus.org@gnu.org Xref: main.gmane.org gmane.emacs.devel:14302 X-Report-Spam: http://spam.gmane.org/gmane.emacs.devel:14302 Luc Teirlinck writes: > Stefan Monnier wrote: > > Yes, we need to address those. Making invisible front-sticky and > not rear-sticky (in the info buffer) is easy enough. > > Yes although, as you pointed out, that might in certain situations > produce non-intuitive results for commands that check char-before > (or both char-before and char-after) for what to do. Of course. The purpose of the invisible property is to actually have the characters in question appear in the buffer. If you wanted to attach some information to text that would _not_ influence editing, you would put it into text properties, for example. > To make things worse, the invisibility property is not the only text > property that appears to give problems of the "things are not always > what they really seem" type. The display property can be just as > bad. Again, the purpose of this property is to make things different from what they really seem, so it is hardly surprising that it succeeds. > echo: (sh-utils)echo invocation. Print a line of text. > > The user does not see the: > > : (sh-utils)echo invocation. > > But to play semantic games (that have some relevance), that text is > completely "visible" (line-move-invisible returns nil for all involved > positions and there are no invisibility properties around). It just > has the display property. > > All of this would seem to be very confusing to the user. Which is the reason one would have to fix this right there in the code at the place of usage. One can't cook up semantics for invisible and display that will be perfect in all situations, so one has to cater for those situations explicitly where it turns out the chosen alternative does not fit. -- David Kastrup, Kriemhildstr. 15, 44793 Bochum