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.devel Subject: Re: noverlay branch Date: Tue, 27 Sep 2022 14:45:46 -0400 Message-ID: References: <87bkr1e6yb.fsf@rfc20.org> <83ill9joji.fsf@gnu.org> <877d1oenc7.fsf@rfc20.org> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="37590"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/29.0.50 (gnu/linux) Cc: Eli Zaretskii , emacs-devel@gnu.org To: Matt Armstrong Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Tue Sep 27 20:50:14 2022 Return-path: Envelope-to: ged-emacs-devel@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 1odFen-0009Xc-Q0 for ged-emacs-devel@m.gmane-mx.org; Tue, 27 Sep 2022 20:50:14 +0200 Original-Received: from localhost ([::1]:40532 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1odFem-0008KL-PK for ged-emacs-devel@m.gmane-mx.org; Tue, 27 Sep 2022 14:50:12 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:41024) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1odFae-0004nU-Fn for emacs-devel@gnu.org; Tue, 27 Sep 2022 14:45:56 -0400 Original-Received: from mailscanner.iro.umontreal.ca ([132.204.25.50]:57611) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1odFac-0005Uy-27; Tue, 27 Sep 2022 14:45:55 -0400 Original-Received: from pmg2.iro.umontreal.ca (localhost.localdomain [127.0.0.1]) by pmg2.iro.umontreal.ca (Proxmox) with ESMTP id 538128071D; Tue, 27 Sep 2022 14:45:49 -0400 (EDT) Original-Received: from mail01.iro.umontreal.ca (unknown [172.31.2.1]) by pmg2.iro.umontreal.ca (Proxmox) with ESMTP id BC0298005E; Tue, 27 Sep 2022 14:45:47 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=iro.umontreal.ca; s=mail; t=1664304347; bh=xiab+bx6X7xsUTWbA3rWi/XSbv3JhLRpSwAmO7KkGPI=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=ONH9fCOJCfK/owHFTNuSk7+6Hmc3M9J8Hmil8AC0AuVPWGJRHnEKIBSxBhzWL67K5 O2EAPAcVwFkd7jqBLbgO9XhZjnyEib4c7nLQnb3QBa/3qIJgf+6rIrc+bnkKnk1FSY Phs58tCAjY59251vxV7JN2g7J0v9+5yzPcCAVTGb3LV4jTygExh4W2DMWV5wzoBGNb 4GbCM6d8NRlyDtw2TeCyeAOlQV6M33UAL4CcD3BjS/6/aaa5CS/cIOfjmFVzlFIgAC Fw5g0707LFD3hnrwDa7v9/BdSEeW9W3r84CLGhgzra205RvyEpdO9UZfjk0I6EXWm/ 53vBhxgwNUfdw== Original-Received: from lechazo (lechon.iro.umontreal.ca [132.204.27.242]) by mail01.iro.umontreal.ca (Postfix) with ESMTPSA id AC403120392; Tue, 27 Sep 2022 14:45:47 -0400 (EDT) In-Reply-To: <877d1oenc7.fsf@rfc20.org> (Matt Armstrong's message of "Tue, 27 Sep 2022 10:31:04 -0700") 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 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.29 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-mx.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.io gmane.emacs.devel:296368 Archived-At: >> Of the rest, item 1 sounds like the most important one, but do you >> have ideas for how to achieve that? > I think (3) -- improving the comments -- is a good starting point, Not only that. It's an important end in itself. Even if you don't know what the code does or why it does something, writing it as a comment can be very useful (can help someone else, who does understand the code, notice that it deserves an explanation). > My idea is: store each overlay in two trees, one ordered by ascending > BEG and one ordered by descending END. These are the similar to the > current "overlays before" and "overlays after" linked lists, except that > the "overlay center" is gone and replaced by O(log N) lookups. (In fact > we could retain the idea of an "overlay center" by maintaining a > "finger" node in each tree...but I digress...) I don't want to discourage you, but please do remember that we have lived with a "ridiculously inefficient" implementation for the last 30 years or so, and that keeping two trees comes at a cost (coding/maintenance cost + runtime cost + heapsize cost). Stefan