From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Ian Price Newsgroups: gmane.lisp.guile.user Subject: Re: Syntax-rules generate symbol Date: Tue, 10 Sep 2013 11:38:38 +0100 Message-ID: <874n9tneq9.fsf@Kagami.home> References: <87txhuarxf.fsf@gnu.org> <871u4xdaow.fsf@taylan.uni.cx> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1378809536 22395 80.91.229.3 (10 Sep 2013 10:38:56 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Tue, 10 Sep 2013 10:38:56 +0000 (UTC) Cc: "guile-user@gnu.org" To: Panicz Maciej Godek Original-X-From: guile-user-bounces+guile-user=m.gmane.org@gnu.org Tue Sep 10 12:39:00 2013 Return-path: Envelope-to: guile-user@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1VJLLX-0003bw-TH for guile-user@m.gmane.org; Tue, 10 Sep 2013 12:39:00 +0200 Original-Received: from localhost ([::1]:56911 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VJLLX-00044x-Av for guile-user@m.gmane.org; Tue, 10 Sep 2013 06:38:59 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:51737) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VJLLL-00044h-62 for guile-user@gnu.org; Tue, 10 Sep 2013 06:38:51 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VJLLH-0005gM-3m for guile-user@gnu.org; Tue, 10 Sep 2013 06:38:47 -0400 Original-Received: from mail-wg0-x22b.google.com ([2a00:1450:400c:c00::22b]:32856) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VJLLG-0005gI-Se for guile-user@gnu.org; Tue, 10 Sep 2013 06:38:43 -0400 Original-Received: by mail-wg0-f43.google.com with SMTP id z12so6252134wgg.34 for ; Tue, 10 Sep 2013 03:38:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=20120113; h=from:to:cc:subject:references:mail-followup-to:date:in-reply-to :message-id:user-agent:mime-version:content-type; bh=bKx22URVLfHrBzflasODO0yI+/rr6/8avexIY1Q3PIs=; b=D5nXiN+femVmUEKPcRk7zI/TBbedSyJGC2/d7aIJWTvlWeNiGfOY5YfLEkN5uZcZTS 03MdzpjgEaBliiXksQqhJgC/FGVTsB38DgpVeT9UO7OR5XEL4CMfky/uPaZAVMW9rmVm ieixQeQnNVMsML0S80gT03sWRXmpvGyj5AhWyJ0H+8J+6SeoSy6/O6o5NPEaJ9hFW0gO c2SoP3096MpVK1+ax4qL7abvQZjCMR+goTzszdE7+lhVHSsOdTHGaRjyLB9PKS8yp61H 2VpQbcyIcOCFudxXbV2Q25XeygAvUIfc3EN5/I3hyYpv13Q9sM2/x+A87ldV58tPxcIM l90Q== X-Received: by 10.180.24.198 with SMTP id w6mr12373789wif.1.1378809521980; Tue, 10 Sep 2013 03:38:41 -0700 (PDT) Original-Received: from Kagami.home (host109-157-170-145.range109-157.btcentralplus.com. [109.157.170.145]) by mx.google.com with ESMTPSA id b13sm2345103wiv.1.1969.12.31.16.00.00 (version=TLSv1.2 cipher=RC4-SHA bits=128/128); Tue, 10 Sep 2013 03:38:40 -0700 (PDT) Mail-Followup-To: Panicz Maciej Godek , "guile-user\@gnu.org" In-Reply-To: (Panicz Maciej Godek's message of "Tue, 10 Sep 2013 08:11:09 +0200") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.1 (gnu/linux) X-detected-operating-system: by eggs.gnu.org: Error: Malformed IPv6 address (bad octet value). X-Received-From: 2a00:1450:400c:c00::22b X-BeenThere: guile-user@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: General Guile related discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: guile-user-bounces+guile-user=m.gmane.org@gnu.org Original-Sender: guile-user-bounces+guile-user=m.gmane.org@gnu.org Xref: news.gmane.org gmane.lisp.guile.user:10789 Archived-At: Panicz Maciej Godek writes: > I assume that the main reason for using this is efficiency (rather > than simplicity), because allegedly guile's continuations are rather > inefficient. Primarily, it's an efficiency hack, but you can also make a case that it better if you can tell at a glance that the continuation will never be stored, similar to how we have conventions for predicates and so forth. > On one hand, it's good to know that (and would be even better > to be able to find it out by skimming section 6.13 of the manual), It is documented in section 13.5.1. > but on the other it would be nicer if the compiler could trace the > usages of continuations and figure out whether a given one is > ever being re-entered, and optimize accordingly. Well, it can sometimes, but it's a hard analysis in general. -- Ian Price -- shift-reset.com "Programming is like pinball. The reward for doing it well is the opportunity to do it again" - from "The Wizardy Compiled"