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Re: IRIs, URIs, TAG issues 15 and 27

From: Martin Duerst <duerst@w3.org>
Date: Thu, 17 Apr 2003 17:41:43 -0400
Message-Id: <>
To: Tim Bray <tbray@textuality.com>, WWW-Tag <www-tag@w3.org>, uri@w3.org, public-iri@w3.org

Hello Tim,

Many thanks for your message. Can you (and everybody else)
please make sure that you copy public-iri@w3.org for IRI-related
issues? Many thanks in advance.

Regarding the issue of coherent round-tripping IRI->URI->IRI,
I suggest
as required reading.

Regards,    Martin.

At 16:30 03/04/14 -0700, Tim Bray wrote:

>The TAG has two issues on its plate, 
>http://www.w3.org/2001/tag/ilist#URIEquivalence-15 (essentially: when are 
>two URIs considered equivalent?) and
>http://www.w3.org/2001/tag/ilist#IRIEverywhere-27 (essentially: what 
>should we do about IRIs?).
>I, with lots of TAG input, drafted some text on the comparison issue, most 
>of which has now made it into the latest draft of the RFC2396 revision at 
>We've spun our wheels on this quite a bit and failed to record much 
>progress.  However, I feel that we do have quite a bit of consensus 
>lurking and we can move forward on these issues.
>I suspect that we agree on the following:
>1. In response to the basic question asked by Jonathan Marsh et al in 
>Issue 27, the TAG answers, first of all, "Yes".  That is, we believe that 
>it is important that Web identifiers be able to use non-ASCII characters 
>natively and straightforwardly, and that the IRI work (see 
>http://www.w3.org/International/iri-edit/) is sound and is making good 
>progress.  That said, the draft is not yet stable or finalized, and we 
>agree with the concern addressed by Marsh et al about the risk involved 
>when referencing unstable standards.  As of now, both XML 1.* and XML 
>Schema's "AnyURI" work define a construct where IRIs may be used, and the 
>benefit seems to justify the risk.
>2. The TAG notes that, with the blessing of the XML Namespaces 
>recommendation, some software is observed to take decisions about URI 
>equivalence on the basis of strcmp() or its equivalent.  This is 
>widespread enough that it's not going to go away.
>3. The TAG urges both spec and software authors to familiarize themselves 
>with the issues around URI comparison as laid out in RFC2396bis, 
>4. Because of the prevalence of simple string comparison of URIs, and 
>because of the Web Architectural principle that consistency in naming is 
>important, the TAG urges creators of URIs to create them in as canonical a 
>form as possible.  Section 6.3 of the RFC2396bis draft provides rules for 
>this that are applicable both to URIs and IRIs.  This will have the 
>beneficial effect that strcmp() will be an accurate (and very cheap) 
>equivalence test.
>Following on from this, TimBL keeps raising the importance of coherent 
>round-tripping IRI->URI->IRI, but I've not quite managed to grasp the core 
>of that issue fully enough to tell whether we really have consensus; Tim, 
>any chance of outlining that one in writing or have you already?
>We can't close our issue 15 until the RFC2396 redrafting is finished, but 
>given the above, I think we can close #27.
>Cheers, Tim Bray
>         (ongoing fragmented essay: http://www.tbray.org/ongoing/)
Received on Thursday, 17 April 2003 17:42:27 UTC

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