From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.devel Subject: Re: Overlays as an AA-tree Date: Tue, 21 Feb 2017 10:11:56 -0500 Message-ID: References: <87d1jylv43.fsf@fastmail.com> <87fujvpkzc.fsf@fastmail.com> <87vasr5tqd.fsf@hochschule-trier.de> <87d1ex4kon.fsf@hochschule-trier.de> <87d1evod6x.fsf@fastmail.com> <877f53ftab.fsf@hochschule-trier.de> <878tpiqiuc.fsf@hochschule-trier.de> <87shnppspb.fsf@hochschule-trier.de> <87o9yc9v30.fsf@hochschule-trier.de> <87a89vaes3.fsf@hochschule-trier.de> <87efz7n0g5.fsf@fastmail.com> <877f4uah6i.fsf@hochschule-trier.de> <83k28u1uyz.fsf@gnu.org> <871suxs9ad.fsf@hochschule-trier.de> <837f4pxpdc.fsf@gnu.org> <877f4lls9e.fsf@hochschule-trier.de> <838tp0q3k8.fsf@gnu.org> <87vas4owus.fsf@luca> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: blaine.gmane.org 1487694415 31115 195.159.176.226 (21 Feb 2017 16:26:55 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Tue, 21 Feb 2017 16:26:55 +0000 (UTC) User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.0.50 (gnu/linux) To: emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Tue Feb 21 17:26:50 2017 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1cgDH4-0007KN-RW for ged-emacs-devel@m.gmane.org; Tue, 21 Feb 2017 17:26:46 +0100 Original-Received: from localhost ([::1]:46699 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cgDHA-0007UH-Bq for ged-emacs-devel@m.gmane.org; Tue, 21 Feb 2017 11:26:52 -0500 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:48064) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cgC6v-0003es-Bx for emacs-devel@gnu.org; Tue, 21 Feb 2017 10:12:14 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cgC6r-0004JR-Ek for emacs-devel@gnu.org; Tue, 21 Feb 2017 10:12:13 -0500 Original-Received: from [195.159.176.226] (port=33629 helo=blaine.gmane.org) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1cgC6r-0004Iy-6Z for emacs-devel@gnu.org; Tue, 21 Feb 2017 10:12:09 -0500 Original-Received: from list by blaine.gmane.org with local (Exim 4.84_2) (envelope-from ) id 1cgC6e-0004ZQ-Tv for emacs-devel@gnu.org; Tue, 21 Feb 2017 16:11:56 +0100 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 26 Original-X-Complaints-To: usenet@blaine.gmane.org Cancel-Lock: sha1:YTRuHIBde7wmBerDs/zYSkybXlw= X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 195.159.176.226 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.org gmane.emacs.devel:212523 Archived-At: > Ideally, I think, this last detail should be of no consequence and the > implementation should only be limited by the number of overlays and not > by where in the buffer they occur. Luckily, it's not currently a problem we really face. Instead the problem we face is how to handle a large number of overlays in a buffer, but where any given buffer position is only covered by a modest number of overlays. The problem of handling efficiently a large number of overlays covering a given position seems pretty hard to solve, actually. > I think I'm going to relax now. BTW, in your new overlay representation, how many bytes (or words) does an overlay cost (in the master tree, if I count right, an overlay costs 3 Lisp_Misc objects, so that should be 3x 6words, i.e. 72 bytes on a 32bit system)? I'd expect the new representation to be no larger (the current representation has a lot of redundancy). But I'm curious because, depending on the answer, the whole Lisp_Misc thingy might want to be reconsidered. Stefan