From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 21497 invoked by alias); 14 Oct 2011 20:03:24 -0000 Received: (qmail 21489 invoked by uid 22791); 14 Oct 2011 20:03:23 -0000 X-SWARE-Spam-Status: No, hits=-7.2 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_HI,RP_MATCHES_RCVD,SPF_HELO_PASS X-Spam-Check-By: sourceware.org Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Fri, 14 Oct 2011 20:03:07 +0000 Received: from int-mx12.intmail.prod.int.phx2.redhat.com (int-mx12.intmail.prod.int.phx2.redhat.com [10.5.11.25]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id p9EK35q6019196 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Fri, 14 Oct 2011 16:03:05 -0400 Received: from ns3.rdu.redhat.com (ns3.rdu.redhat.com [10.11.255.199]) by int-mx12.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id p9EK34qw016680; Fri, 14 Oct 2011 16:03:05 -0400 Received: from barimba (ovpn01.gateway.prod.ext.phx2.redhat.com [10.5.9.1]) by ns3.rdu.redhat.com (8.13.8/8.13.8) with ESMTP id p9EK33HS030056; Fri, 14 Oct 2011 16:03:03 -0400 From: Tom Tromey To: Paul Koning Cc: gdb-patches@sourceware.org Subject: Re: Python: fetch value when building gdb.Value object References: <36B29E9D-F2B3-446F-AF8A-97254A3AAEE2@comcast.net> <21467A42-84A3-4DFD-83A9-28FFFB0A5C7F@comcast.net> Date: Fri, 14 Oct 2011 20:03:00 -0000 In-Reply-To: <21467A42-84A3-4DFD-83A9-28FFFB0A5C7F@comcast.net> (Paul Koning's message of "Tue, 4 Oct 2011 11:51:00 -0400") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.0.90 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2011-10/txt/msg00422.txt.bz2 >>>>> "Paul" == Paul Koning writes: Tom> I am not convinced that this is the right approach. Tom> I think it would probably be better to expose the laziness to the Python Tom> programmer -- via a new attribute and a new method to un-lazy the Tom> object. Tom> The reason is that eager fetching can be very expensive. E.g., you may Tom> construct an intermediate value that is a very large array, but intend Tom> only to reference a few elements. This can be done efficiently by gdb, Tom> but eager fetching will defeat that. Paul> I modeled what I did after the way the existing GDB code handles Paul> convenience variables. Convenience variables aren't really the best model. First, they are very old, probably predating anybody worrying about this stuff. Second, the CLI isn't really a fully-featured programming language. Tom