From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: David Kastrup Newsgroups: gmane.lisp.guile.devel Subject: Re: A plea for local-eval in 2.0.4 Date: Sat, 14 Jan 2012 09:59:32 +0100 Organization: Organization?!? Message-ID: <87r4z264nf.fsf@fencepost.gnu.org> References: <87aa5s8uli.fsf@netris.org> <8762gg7yco.fsf@fencepost.gnu.org> <8739bj8tem.fsf@netris.org> <87boq777xz.fsf@fencepost.gnu.org> <87pqen6qho.fsf@netris.org> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: dough.gmane.org 1326531596 22444 80.91.229.12 (14 Jan 2012 08:59:56 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Sat, 14 Jan 2012 08:59:56 +0000 (UTC) To: guile-devel@gnu.org Original-X-From: guile-devel-bounces+guile-devel=m.gmane.org@gnu.org Sat Jan 14 09:59:52 2012 Return-path: Envelope-to: guile-devel@m.gmane.org Original-Received: from lists.gnu.org ([140.186.70.17]) by lo.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1RlzSq-000112-2j for guile-devel@m.gmane.org; Sat, 14 Jan 2012 09:59:52 +0100 Original-Received: from localhost ([::1]:39154 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RlzSp-0007sx-KG for guile-devel@m.gmane.org; Sat, 14 Jan 2012 03:59:51 -0500 Original-Received: from eggs.gnu.org ([140.186.70.92]:54155) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RlzSn-0007sr-D8 for guile-devel@gnu.org; Sat, 14 Jan 2012 03:59:50 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RlzSm-0002qG-7z for guile-devel@gnu.org; Sat, 14 Jan 2012 03:59:49 -0500 Original-Received: from lo.gmane.org ([80.91.229.12]:55816) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RlzSl-0002qB-QP for guile-devel@gnu.org; Sat, 14 Jan 2012 03:59:48 -0500 Original-Received: from list by lo.gmane.org with local (Exim 4.69) (envelope-from ) id 1RlzSi-0000yS-Eo for guile-devel@gnu.org; Sat, 14 Jan 2012 09:59:44 +0100 Original-Received: from p508ea5b6.dip.t-dialin.net ([80.142.165.182]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sat, 14 Jan 2012 09:59:44 +0100 Original-Received: from dak by p508ea5b6.dip.t-dialin.net with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sat, 14 Jan 2012 09:59:44 +0100 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 33 Original-X-Complaints-To: usenet@dough.gmane.org X-Gmane-NNTP-Posting-Host: p508ea5b6.dip.t-dialin.net X-Face: 2FEFf>]>q>2iw=B6, xrUubRI>pR&Ml9=ao@P@i)L:\urd*t9M~y1^:+Y]'C0~{mAl`oQuAl \!3KEIp?*w`|bL5qr,H)LFO6Q=qx~iH4DN; i"; /yuIsqbLLCh/!U#X[S~(5eZ41to5f%E@'ELIi$t^ Vc\LWP@J5p^rst0+('>Er0=^1{]M9!p?&:\z]|;&=NP3AhB!B_bi^]Pfkw User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.0.92 (gnu/linux) Cancel-Lock: sha1:3Cjhd2sOr1h18X7mLg5h24hJ9XI= X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6 (newer, 3) X-Received-From: 80.91.229.12 X-BeenThere: guile-devel@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "Developers list for Guile, the GNU extensibility library" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: guile-devel-bounces+guile-devel=m.gmane.org@gnu.org Original-Sender: guile-devel-bounces+guile-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.lisp.guile.devel:13487 Archived-At: Mark H Weaver writes: > Probably the easiest way to think about it is that (the-environment) > acts like (list (lambda () ) ...), with one `lambda' for each > expression that you will later pass to `local-eval'. Calling > `local-eval' simply calls the appropriate procedure in that list. Well, I experimented around a bit with lambda. How does this work in practice? In Guilev1, the module is probably recorded as part of the procedure-environment. In Guilev2, a variable reference is compiled? How does that work when there is no such variable? It gets created with an undefined binding? > Calling the procedure created by a lambda expression evaluates the > lambda body within the _lexical_ environment of the lambda expression, > but within the _dynamic_ environment of the procedure call. Top-level > variables are part of the _lexical_ environment. That means that > top-level variable references within a procedure are looked up in the > module where the procedure was defined, _not_ the (current-module) at > the time of the procedure call. Ok, here is the clincher and probably what I have actually confused this with (it is a thin line): within local-eval, what is the return value of calling (current-module)? I would expect that it is the same as outside of local-eval so that (define x 5) inside of local-eval would _not_ be equivalent to (module-define! (current-module) 'x 5) as the first one would take the current module at the-environment time, and the second one would take it at local-eval time. Correct? -- David Kastrup