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: [PATCH] Add new lisp function length= with bytecode support Date: Tue, 07 Mar 2017 21:46:28 -0500 Message-ID: References: NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: blaine.gmane.org 1488941215 5341 195.159.176.226 (8 Mar 2017 02:46:55 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Wed, 8 Mar 2017 02:46:55 +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 Wed Mar 08 03:46:51 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 1clRcl-0000MJ-AX for ged-emacs-devel@m.gmane.org; Wed, 08 Mar 2017 03:46:47 +0100 Original-Received: from localhost ([::1]:53627 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1clRco-00041C-7w for ged-emacs-devel@m.gmane.org; Tue, 07 Mar 2017 21:46:50 -0500 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:41298) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1clRcf-0003zk-HC for emacs-devel@gnu.org; Tue, 07 Mar 2017 21:46:42 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1clRcc-0001wL-Av for emacs-devel@gnu.org; Tue, 07 Mar 2017 21:46:41 -0500 Original-Received: from [195.159.176.226] (port=34391 helo=blaine.gmane.org) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1clRcc-0001w3-4O for emacs-devel@gnu.org; Tue, 07 Mar 2017 21:46:38 -0500 Original-Received: from list by blaine.gmane.org with local (Exim 4.84_2) (envelope-from ) id 1clRcS-0007KO-Qj for emacs-devel@gnu.org; Wed, 08 Mar 2017 03:46:28 +0100 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 19 Original-X-Complaints-To: usenet@blaine.gmane.org Cancel-Lock: sha1:la4DYrcguj29S65e+WeYkiU0+Ew= 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:212823 Archived-At: > This is beginning to feel like bike-shedding. Indeed. I guess part of the problem is a lack of direction: is there some benchmark or test case that drives your desire to add that bytecode? You say that you've found a large proportion of calls to `length` where the result is then compared to a number, so it could be sped up. I do not doubt that it is the case, but the question is whether this speed up makes a difference in practice. If it does, then we can compare the different options. BTW, AFAIK there are 4 options (in order of increasing performance): - leave things as they are. - implement length= in Elisp. - implement length= in C (but without dedicating a bytecode to it). - implement length= as a bytecode. Stefan