From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: ludo@gnu.org (Ludovic =?iso-8859-1?Q?Court=E8s?=) Newsgroups: gmane.lisp.guile.devel Subject: Re: Enhancement to the syntax system? Date: Mon, 02 Jul 2012 21:28:29 +0200 Message-ID: <877gumufmq.fsf@gnu.org> References: NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Trace: dough.gmane.org 1341257341 25092 80.91.229.3 (2 Jul 2012 19:29:01 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Mon, 2 Jul 2012 19:29:01 +0000 (UTC) To: guile-devel@gnu.org Original-X-From: guile-devel-bounces+guile-devel=m.gmane.org@gnu.org Mon Jul 02 21:29:00 2012 Return-path: Envelope-to: guile-devel@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 1SlmIt-0005r0-GE for guile-devel@m.gmane.org; Mon, 02 Jul 2012 21:28:59 +0200 Original-Received: from localhost ([::1]:41640 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SlmIs-0002t4-Gm for guile-devel@m.gmane.org; Mon, 02 Jul 2012 15:28:58 -0400 Original-Received: from eggs.gnu.org ([208.118.235.92]:34488) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SlmIc-0002F8-WD for guile-devel@gnu.org; Mon, 02 Jul 2012 15:28:44 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1SlmIb-0005KD-Cb for guile-devel@gnu.org; Mon, 02 Jul 2012 15:28:42 -0400 Original-Received: from plane.gmane.org ([80.91.229.3]:45220) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SlmIb-0005Jv-6A for guile-devel@gnu.org; Mon, 02 Jul 2012 15:28:41 -0400 Original-Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1SlmIZ-0005GK-8h for guile-devel@gnu.org; Mon, 02 Jul 2012 21:28:39 +0200 Original-Received: from reverse-83.fdn.fr ([80.67.176.83]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Mon, 02 Jul 2012 21:28:39 +0200 Original-Received: from ludo by reverse-83.fdn.fr with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Mon, 02 Jul 2012 21:28:39 +0200 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 30 Original-X-Complaints-To: usenet@dough.gmane.org X-Gmane-NNTP-Posting-Host: reverse-83.fdn.fr X-URL: http://www.fdn.fr/~lcourtes/ X-Revolutionary-Date: 15 Messidor an 220 de la =?iso-8859-1?Q?R=E9volution?= X-PGP-Key-ID: 0xEA52ECF4 X-PGP-Key: http://www.fdn.fr/~lcourtes/ludovic.asc X-PGP-Fingerprint: 83C4 F8E5 10A3 3B4C 5BEA D15D 77DD 95E2 EA52 ECF4 X-OS: x86_64-unknown-linux-gnu User-Agent: Gnus/5.130005 (Ma Gnus v0.5) Emacs/24.1 (gnu/linux) Cancel-Lock: sha1:jMpD8Ti5MyfUiwbjwTmIiYxFus8= X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 80.91.229.3 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:14687 Archived-At: Hi Stefan, Stefan Israelsson Tampe skribis: > Hygiene is harder to maintain. e.g. I kept on hitting this kind of code > snippets > > #'(let ((x v)) > #,(f rest #'x)) > > The problem with this code is hygiene, I need to make a gensym and use > with-syntax to bound x to that gensym in order to be safe > at the macro expansion. What do you mean? Here ‘x’ leads to a newly introduced binding. Likewise, the code below doesn’t introduce bindings non-hygienic bindings, and is non-ambiguous: (macroexpand '(let-syntax ((f (lambda (s) (syntax-case s () ((_ x y) #`(let ((p x)) (+ p #,(identity #'y)))))))) (f 1 2))) => # Thanks, Ludo’.