From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Andy Wingo Newsgroups: gmane.lisp.guile.devel Subject: Re: mark uniqueness Date: Wed, 25 Jan 2012 10:02:45 +0100 Message-ID: <87wr8gjgsq.fsf@pobox.com> References: <874nvw99za.fsf@pobox.com> <87zkdo7uf5.fsf@pobox.com> <87sjjbvs12.fsf@pobox.com> <87sjjaunme.fsf@netris.org> <87r4yurruv.fsf@pobox.com> <87obtyuj4k.fsf@netris.org> <871uqqpfoo.fsf@pobox.com> <87hazmrv15.fsf@netris.org> <87zkdem58t.fsf@pobox.com> <87d3a9mjcy.fsf@pobox.com> <874nvls04f.fsf@netris.org> <87mx9clu9p.fsf_-_@pobox.com> <87r4yor5j7.fsf@netris.org> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: dough.gmane.org 1327482188 14555 80.91.229.12 (25 Jan 2012 09:03:08 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Wed, 25 Jan 2012 09:03:08 +0000 (UTC) Cc: Peter TB Brett , guile-devel@gnu.org To: Mark H Weaver Original-X-From: guile-devel-bounces+guile-devel=m.gmane.org@gnu.org Wed Jan 25 10:03:04 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 1Rpykx-00068v-QH for guile-devel@m.gmane.org; Wed, 25 Jan 2012 10:03:03 +0100 Original-Received: from localhost ([::1]:50798 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Rpykx-00038X-BG for guile-devel@m.gmane.org; Wed, 25 Jan 2012 04:03:03 -0500 Original-Received: from eggs.gnu.org ([140.186.70.92]:55052) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Rpykm-0002uq-72 for guile-devel@gnu.org; Wed, 25 Jan 2012 04:03:01 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Rpykk-0005Tm-P6 for guile-devel@gnu.org; Wed, 25 Jan 2012 04:02:52 -0500 Original-Received: from a-pb-sasl-sd.pobox.com ([74.115.168.62]:63974 helo=sasl.smtp.pobox.com) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Rpykk-0005Tg-Gi for guile-devel@gnu.org; Wed, 25 Jan 2012 04:02:50 -0500 Original-Received: from sasl.smtp.pobox.com (unknown [127.0.0.1]) by a-pb-sasl-sd.pobox.com (Postfix) with ESMTP id EFB655EC5; Wed, 25 Jan 2012 04:02:49 -0500 (EST) DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=pobox.com; h=from:to:cc :subject:references:date:in-reply-to:message-id:mime-version :content-type; s=sasl; bh=Ti093AOzl1rcdKLmeH8w8w5O7uk=; b=r18T5j BN8dJhj0jgU9KVHS89b6VyuV5/5gXkh7j/5P75RrN7HMGurSrvCD/DWDJ8yzgqFp TXfZ4ikk5dcdNW8ZoAh6HAEHIKoUJYNMRaNAVommy+k3gOveR2D5qkMVRO5Qnc5j WKVa59/SV6nii2SZWeaXulBsJNhM7pPi4PO+w= DomainKey-Signature: a=rsa-sha1; c=nofws; d=pobox.com; h=from:to:cc :subject:references:date:in-reply-to:message-id:mime-version :content-type; q=dns; s=sasl; b=XjXjzNXYIHx25LpGCKpEG5TVsg6uAVPz JoTFSbR9/a+WwrryiDYSP9Mub9es+TP5I6h4AKxQyqF8JSvERt7x7kv8mJyALf2I RSInuo5taMdyaOE/4Xv/OmmM1bCe1Si961VAMJktxqxZIkO+7/eRCQDRky+s75yJ QaghGYmfH1U= Original-Received: from a-pb-sasl-sd.pobox.com (unknown [127.0.0.1]) by a-pb-sasl-sd.pobox.com (Postfix) with ESMTP id E6A845EC4; Wed, 25 Jan 2012 04:02:49 -0500 (EST) Original-Received: from badger (unknown [90.164.198.39]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by a-pb-sasl-sd.pobox.com (Postfix) with ESMTPSA id 509A35EC3; Wed, 25 Jan 2012 04:02:49 -0500 (EST) In-Reply-To: <87r4yor5j7.fsf@netris.org> (Mark H. Weaver's message of "Tue, 24 Jan 2012 19:26:36 -0500") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.3 (gnu/linux) X-Pobox-Relay-ID: 5B140E20-4733-11E1-A489-65B1DE995924-02397024!a-pb-sasl-sd.pobox.com X-detected-operating-system: by eggs.gnu.org: Solaris 10 (beta) X-Received-From: 74.115.168.62 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:13670 Archived-At: On Wed 25 Jan 2012 01:26, Mark H Weaver writes: > Andy Wingo writes: > >> (define-syntax-rule (define-const x val) >> (begin >> (define t val) >> (define-syntax x (identifier-syntax t)))) >> >> Here, `t' will have a fresh mark. >> >> Now, if in one compilation unit, I do: >> >> (define-const x 10) >> >> And in another, I do: >> >> (let ((t 20)) >> x) => ? >> >> You would expect the result to be 20. But I think it could be 20, if >> the marks on the two "t"s happened to collide. FWIW I think this example wasn't quite right; you'd need to have the case where both "t"s that are visible have marks. Like in compilation unit B: (let () (define-const y 20) x) => ? Cheers, Andy -- http://wingolog.org/