[Lucid] Please clarify the i's in Appendix A

Shawn Steele <Shawn.Steele@microsoft.com> Fri, 20 March 2015 00:02 UTC

Return-Path: <Shawn.Steele@microsoft.com>
X-Original-To: lucid@ietfa.amsl.com
Delivered-To: lucid@ietfa.amsl.com
Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 8C06F1A01A8 for <lucid@ietfa.amsl.com>; Thu, 19 Mar 2015 17:02:20 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -3.901
X-Spam-Level:
X-Spam-Status: No, score=-3.901 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, GB_I_LETTER=-2, HTML_MESSAGE=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001] autolearn=ham
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id JLsSvQeRu9Du for <lucid@ietfa.amsl.com>; Thu, 19 Mar 2015 17:02:18 -0700 (PDT)
Received: from na01-bn1-obe.outbound.protection.outlook.com (mail-bn1on0798.outbound.protection.outlook.com [IPv6:2a01:111:f400:fc10::798]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id D28F81A0167 for <lucid@ietf.org>; Thu, 19 Mar 2015 17:02:17 -0700 (PDT)
Received: from BLUPR03MB1378.namprd03.prod.outlook.com (25.163.81.12) by BLUPR03MB1380.namprd03.prod.outlook.com (25.163.81.139) with Microsoft SMTP Server (TLS) id 15.1.112.19; Fri, 20 Mar 2015 00:01:58 +0000
Received: from BLUPR03MB1378.namprd03.prod.outlook.com ([25.163.81.12]) by BLUPR03MB1378.namprd03.prod.outlook.com ([25.163.81.12]) with mapi id 15.01.0112.000; Fri, 20 Mar 2015 00:01:58 +0000
From: Shawn Steele <Shawn.Steele@microsoft.com>
To: "lucid@ietf.org" <lucid@ietf.org>
Thread-Topic: Please clarify the i's in Appendix A
Thread-Index: AdBin+ZuKs3zpeT0SS+0IvxOVk8XSg==
Date: Fri, 20 Mar 2015 00:01:58 +0000
Message-ID: <BLUPR03MB1378FED1AEB1C756C5D058C2820E0@BLUPR03MB1378.namprd03.prod.outlook.com>
Accept-Language: en-US
Content-Language: en-US
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
x-originating-ip: [2001:4898:80e8:ee31::2]
authentication-results: ietf.org; dkim=none (message not signed) header.d=none;
x-microsoft-antispam: UriScan:;BCL:0;PCL:0;RULEID:;SRVR:BLUPR03MB1380;
x-forefront-antispam-report: BMV:1; SFV:NSPM; SFS:(10019020)(86362001)(19300405004)(107886001)(2351001)(110136001)(99286002)(19625215002)(33656002)(46102003)(19617315012)(229853001)(122556002)(40100003)(19580395003)(92566002)(16236675004)(86612001)(15975445007)(102836002)(2900100001)(77156002)(62966003)(450100001)(74316001)(50986999)(2656002)(2501003)(87936001)(54356999)(76576001)(16601075003)(3826002); DIR:OUT; SFP:1102; SCL:1; SRVR:BLUPR03MB1380; H:BLUPR03MB1378.namprd03.prod.outlook.com; FPR:; SPF:None; MLV:sfv; LANG:en;
x-microsoft-antispam-prvs: <BLUPR03MB1380D521D9F04601BB46786E820E0@BLUPR03MB1380.namprd03.prod.outlook.com>
x-exchange-antispam-report-test: UriScan:;
x-exchange-antispam-report-cfa-test: BCL:0; PCL:0; RULEID:(601004)(5002010)(5005006); SRVR:BLUPR03MB1380; BCL:0; PCL:0; RULEID:; SRVR:BLUPR03MB1380;
x-forefront-prvs: 05214FD68E
Content-Type: multipart/alternative; boundary="_000_BLUPR03MB1378FED1AEB1C756C5D058C2820E0BLUPR03MB1378namp_"
MIME-Version: 1.0
X-OriginatorOrg: microsoft.onmicrosoft.com
X-MS-Exchange-CrossTenant-originalarrivaltime: 20 Mar 2015 00:01:58.0270 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 72f988bf-86f1-41af-91ab-2d7cd011db47
X-MS-Exchange-Transport-CrossTenantHeadersStamped: BLUPR03MB1380
Archived-At: <http://mailarchive.ietf.org/arch/msg/lucid/i2jqttz-eS3UG9Ydehh45LeWdqA>
Subject: [Lucid] Please clarify the i's in Appendix A
X-BeenThere: lucid@ietf.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: "Locale-free UniCode Identifiers \(LUCID\)" <lucid.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/lucid>, <mailto:lucid-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/lucid/>
List-Post: <mailto:lucid@ietf.org>
List-Help: <mailto:lucid-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/lucid>, <mailto:lucid-request@ietf.org?subject=subscribe>
X-List-Received-Date: Fri, 20 Mar 2015 00:02:20 -0000

https://datatracker.ietf.org/doc/draft-sullivan-lucid-prob-stmt/?include_text=1 that seems odd to me, where does Unicode document this?

   U+069 vs \u'0069'\u'0307'  LATIN SMALL LETTER I followed by COMBINING
      DOT ABOVE by definition, renders exactly the same as LATIN SMALL
      LETTER I by itself and does so in practice for any good font.  The
      same would be true if "i" was replaced with any of the other
      Soft_Dotted characters defined in Unicode.  The character sequence
      \u'0069'\u'0307' (followed by no other combining mark) is
      reportedly rather common on the Internet.  Because base character
      and stand-alone code point are the same in this case, and the code
      points affected have the Soft_Dotted property already, this could
      be mitigated separately via a context rule affecting U+0307.

IDNA makes this worse by mapping İ U+0130 to U+0069 + U+0307, apparently to get a visual effect.  It seems peculiar to me that there would need to be an exception to the existing exception.

I’d like an attribution for the remark “\u'0069'\u'0307' (followed by no other combining mark) is reportedly rather common on the Internet”.  I’d also be interested in what contexts.  I’d also be curious about how those came into existence.  (NFD followed by lower case?)

-Shawn

 
http://blogs.msdn.com/shawnste
http://L3-G0.blogspot.com