From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED.blaine.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.devel Subject: Re: Lexical binding: why? Date: Tue, 28 May 2019 09:25:04 -0400 Message-ID: References: <20190528100850.GA5296@ACM> <1df3afde-497e-bb67-9cce-5c5d7e5887a6@yandex.ru> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: blaine.gmane.org; posting-host="blaine.gmane.org:195.159.176.226"; logging-data="85697"; mail-complaints-to="usenet@blaine.gmane.org" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.0.50 (gnu/linux) To: emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Tue May 28 15:27:36 2019 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([209.51.188.17]) by blaine.gmane.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:256) (Exim 4.89) (envelope-from ) id 1hVc8d-000M8x-Pz for ged-emacs-devel@m.gmane.org; Tue, 28 May 2019 15:27:35 +0200 Original-Received: from localhost ([127.0.0.1]:35044 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hVc8c-00031l-Ry for ged-emacs-devel@m.gmane.org; Tue, 28 May 2019 09:27:34 -0400 Original-Received: from eggs.gnu.org ([209.51.188.92]:34671) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hVc6O-0001Ot-BN for emacs-devel@gnu.org; Tue, 28 May 2019 09:25:17 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hVc6M-0004QI-Q6 for emacs-devel@gnu.org; Tue, 28 May 2019 09:25:16 -0400 Original-Received: from [195.159.176.226] (port=37830 helo=blaine.gmane.org) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hVc6K-0004Mr-FQ for emacs-devel@gnu.org; Tue, 28 May 2019 09:25:12 -0400 Original-Received: from list by blaine.gmane.org with local (Exim 4.89) (envelope-from ) id 1hVc6H-000JFm-De for emacs-devel@gnu.org; Tue, 28 May 2019 15:25:09 +0200 X-Injected-Via-Gmane: http://gmane.org/ Cancel-Lock: sha1:88urIFzNyaa0MqGOOPw/JPYL8i0= X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] 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:237097 Archived-At: > I think js2-mode in lexical-binding is still ~10% slower than the dynamic > binding mode, Oh, well! I thought we had a better story there :-( Maybe the speed up I remember was linked to the rework I suggested back then to work around the poor lexical-scoping performance (mainly moving a condition-case outside of a loop, IIRC) and that actually improved performance with both lexical and dynamic binding? Stefan