From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Neil Jerram Newsgroups: gmane.lisp.guile.user Subject: Re: Exception API Date: Thu, 07 Sep 2006 23:23:26 +0100 Message-ID: <87fyf348pt.fsf@ossau.uklinux.net> References: <87mz9gt3ia.fsf@laas.fr> <87wt8jkzm5.fsf@zip.com.au> NNTP-Posting-Host: main.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: sea.gmane.org 1157667919 10780 80.91.229.2 (7 Sep 2006 22:25:19 GMT) X-Complaints-To: usenet@sea.gmane.org NNTP-Posting-Date: Thu, 7 Sep 2006 22:25:19 +0000 (UTC) Cc: guile-user@gnu.org Original-X-From: guile-user-bounces+guile-user=m.gmane.org@gnu.org Fri Sep 08 00:25:18 2006 Return-path: Envelope-to: guile-user@m.gmane.org Original-Received: from lists.gnu.org ([199.232.76.165]) by ciao.gmane.org with esmtp (Exim 4.43) id 1GLSIw-0004TO-Jf for guile-user@m.gmane.org; Fri, 08 Sep 2006 00:25:02 +0200 Original-Received: from localhost ([127.0.0.1] helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1GLSIw-00051u-21 for guile-user@m.gmane.org; Thu, 07 Sep 2006 18:25:02 -0400 Original-Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1GLSIr-00051p-TT for guile-user@gnu.org; Thu, 07 Sep 2006 18:24:57 -0400 Original-Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1GLSIr-00051d-CP for guile-user@gnu.org; Thu, 07 Sep 2006 18:24:57 -0400 Original-Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1GLSIr-00051a-9z for guile-user@gnu.org; Thu, 07 Sep 2006 18:24:57 -0400 Original-Received: from [80.84.72.33] (helo=mail3.uklinux.net) by monty-python.gnu.org with esmtp (Exim 4.52) id 1GLSJJ-0006BL-TX for guile-user@gnu.org; Thu, 07 Sep 2006 18:25:26 -0400 Original-Received: from laruns (host86-129-125-104.range86-129.btcentralplus.com [86.129.125.104]) by mail3.uklinux.net (Postfix) with ESMTP id 855F640A4D7; Thu, 7 Sep 2006 22:24:56 +0000 (UTC) Original-Received: from laruns (laruns [127.0.0.1]) by laruns (Postfix) with ESMTP id C6D986F71C; Thu, 7 Sep 2006 23:23:26 +0100 (BST) Original-To: Kevin Ryde In-Reply-To: <87wt8jkzm5.fsf@zip.com.au> (Kevin Ryde's message of "Tue, 05 Sep 2006 08:58:58 +1000") User-Agent: Gnus/5.1007 (Gnus v5.10.7) Emacs/21.4 (gnu/linux) X-BeenThere: guile-user@gnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: General Guile related discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Original-Sender: guile-user-bounces+guile-user=m.gmane.org@gnu.org Errors-To: guile-user-bounces+guile-user=m.gmane.org@gnu.org Xref: news.gmane.org gmane.lisp.guile.user:5498 Archived-At: Kevin Ryde writes: > I had trouble understanding the different dynamic environments > specified for that srfi-34 guard. It looked worryingly like there > could be jumps out of the originating continuation and then back in if > there's a re-throw, which could be pretty slow with guile's > continuations. Yes, I had the same worry. I don't think this is intended, though, and none of the examples in the SRFI do anything so outlandish. Perhaps one of us should raise this with the R6RS committee? (My understanding is that SRFI-34 is regarded as one of the things that will be added to R6RS, and that it is already in pretty much final form.) Assuming that it isn't intended, and that this is clarified in R6RS, we shouldn't need full continuations to implement guard. (If anyone's wondering about the catch-based implementation of guard in srfi/srfi-34.scm, I believe it isn't quite right, but I forgot exactly why.) Regards, Neil _______________________________________________ Guile-user mailing list Guile-user@gnu.org http://lists.gnu.org/mailman/listinfo/guile-user