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: Ideal performance of ELisp Date: Sat, 13 Aug 2022 10:07:04 -0400 Message-ID: References: <83mtceupbx.fsf@gnu.org> <83lerxvfnu.fsf@gnu.org> <838rnxvdcq.fsf@gnu.org> <83r11ptksn.fsf@gnu.org> <83a68dti6w.fsf@gnu.org> <874jykzvx9.fsf@yahoo.com> <83fsi4sttn.fsf@gnu.org> <838rnws5c7.fsf@gnu.org> <838rntocb8.fsf@gnu.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="23923"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/29.0.50 (gnu/linux) Cc: Eli Zaretskii , Po Lu , Alan Mackenzie , emacs-devel , Yuan Fu To: Lynn Winebarger Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Sat Aug 13 16:08:34 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 1oMroW-0005xc-Qi for ged-emacs-devel@m.gmane-mx.org; Sat, 13 Aug 2022 16:08:33 +0200 Original-Received: from localhost ([::1]:39246 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oMroV-0003r8-Gw for ged-emacs-devel@m.gmane-mx.org; Sat, 13 Aug 2022 10:08:31 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:39210) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oMrnG-0003AQ-1o for emacs-devel@gnu.org; Sat, 13 Aug 2022 10:07:14 -0400 Original-Received: from mailscanner.iro.umontreal.ca ([132.204.25.50]:44831) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oMrnC-0002GP-7D; Sat, 13 Aug 2022 10:07:11 -0400 Original-Received: from pmg3.iro.umontreal.ca (localhost [127.0.0.1]) by pmg3.iro.umontreal.ca (Proxmox) with ESMTP id 9AD4B440621; Sat, 13 Aug 2022 10:07:06 -0400 (EDT) Original-Received: from mail01.iro.umontreal.ca (unknown [172.31.2.1]) by pmg3.iro.umontreal.ca (Proxmox) with ESMTP id 6B3954404A6; Sat, 13 Aug 2022 10:07:05 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=iro.umontreal.ca; s=mail; t=1660399625; bh=0UQyNW4zlXD97loT31jRL42nRCDDvikSi6Sy17GvtsI=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=eBxINw/fH5G52fozo51jlu7989WKmMj9/6xkbE+WRkPXSkg68OWkAMkMHVly6GX0u aRYsffKKkkdnqF5S4XfCEX95PZDdRdqebIWSvNAmozF/rekFykuB7g0ZDeSU05Op0i pNEv3Wmud2hjRBjEcQeS+VfhpbDFidL+Lj/Ui928CqZt2wjvxxI54YDOjWsi5HzPRL auhlNJRrrTot7eibos0zFYlpG2WFCKrX2SVy18cdP596KdiOt5EzkCDGZd6CEIrlou k/HCKHbjgoXMhwD5rR/yrBMG+B3AlCF4gsUfxsNUhoVLYzeA+5wwKEOlhcUbsa9N32 QlcYBP7OKnrFA== Original-Received: from pastel (unknown [45.72.195.111]) by mail01.iro.umontreal.ca (Postfix) with ESMTPSA id 20EE1120198; Sat, 13 Aug 2022 10:07:05 -0400 (EDT) In-Reply-To: (Lynn Winebarger's message of "Sat, 13 Aug 2022 06:51:45 -0400") 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, T_SCC_BODY_TEXT_LINE=-0.01 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:293412 Archived-At: >> > Once the VM supports proper tail recursion, it's straightforward to >> > generate automata that never perform a function call, at least not as part >> > of the recognizer. >> >> It was straightforward beforehand as well (using a `while` loop instead >> of recursion). And if you do use recursion, then it's not very much >> simpler with `lexical-binding` than without because you still have to >> take into account the possibility that the function gets redefined >> during your recursion :-( >> > > I think you're mistaking self-tail recursion for tail recursion. No, I was simply restricting the discussion to the case you mention of "generat[ing an] automata", in which case you usually have enough control over the generated code to use a `while` loop if desired. Stefan