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Re: IRI and IDN in RDF

From: Jeremy Carroll <jjc@hplb.hpl.hp.com>
Date: Thu, 13 Jan 2005 09:46:31 +0000
Message-ID: <41E64377.9020605@hplb.hpl.hp.com>
To: Martin Duerst <duerst@w3.org>
Cc: "Krall, Gary" <gkrall@verisign.com>, "'Chris Lilley'" <chris@w3.org>, Reto Bachmann-Gmuer <reto@gmuer.ch>, www-international@w3.org



Martin

when this round of specs come to fruition i.e.
   RFC2396bis
   IRI RFC
   charmod IRI
I guess I would favour a round of normative errata on many specs to 
formally apply the patch.... Hard to tell though, e.g. I suspect the 
hardest is spaces in xsd:anyURI

Jeremy




Martin Duerst wrote:
> 
> At 01:20 05/01/12, Jeremy Carroll wrote:
>  >
>  >
>  >
>  >I suspect that formally correct treatment and good practice diverge on 
> this.
>  >
>  >The text of RDF Concepts and Abstract Syntax which expresses RDF's 
> idea of an IRI is this:
>  >http://www.w3.org/TR/2004/REC-rdf-concepts-20040210/#section-Graph-URIref
>  >[[
> 
> [shortened]
> 
>  >]]
>  >
>  >my understanding is that the IDNs are not covered as such by the 
> conversion stated,
> 
> Yes, because URIs according to RFC2396 don't allow %-encoding in the
> host part.
> 
>  >and any additional conversion required from them would be an extra 
> (non-standard) feature.
> 
> Extra, yes, but not actually any longer non-standard. RFC2396bis
> allows it. So updating the RDF spec to RFC2396bis would fix this,
> at least spec-wise.
> 
> 
>  >I guess from a W3C side we should be revving a lot of text in light of 
> IRI and IDN as they come to fruition.
> 
> Yes. The second point where problems may occur is that RDF currently
> allows spaces and characters such as '<' and '>' directly, whereas
> in IRIs, they are not allowed. There is some text in the IRI spec
> that describes what a spec using IRIs can do in such a case.
> 
> Spec-wise, there would be two choices for RDF:
> 1) Just switching to IRIs, i.e. disallow direct spaces,... in
>    the hope that nobody used them much because they are confusing
>    anyway.
> 2) Saying that a "RDF URI reference" is an IRI after escaping
>    spaces,...
> 
> 1) would probably be the cleaner solution, and would be easier on
>    things such as N3 and SPARCLE.
> 
>  >e.g. the conversion in
>  >http://www.w3.org/International/iri-edit/draft-duerst-iri-10.txt
>  >[[
>  >    http://r&#xE9;sum&#xE9;.example.org may be converted to
>  >    http://xn--rsum-bpad.example.org instead of
>  >    http://r%C3%A9sum%C3%A9.example.org.
>  >]]
>  >and in fact, the first string is not an 'RDF URI reference' or an 
> XLink href attribute value, or in the lexical space of xsd:anyURI, because
>  >    http://r%C3%A9sum%C3%A9.example.org.
>  >is not a legal URI, and the provisions of those specs only allow for 
> %-encoding.
>  >
>  >So, I think an RSS or RDF tool would need either to:
>  >- not check that the URIs were legal
> 
> Because there are very few things you can check with an URI/IRI
> anyway, that's usually a good solution. It also helps with potential
> future changes to URIs/IRIs.
> 
>  >or
>  >- to have an extended check that knew something about IDNs
>  >
>  >and neither is particularly conformant. Personally I would prefer the 
> latter.
> 
> If RDF gets updated to RFC2396bis, you can do that.
> 
> 
> Regards,    Martin.
> 
Received on Thursday, 13 January 2005 09:46:46 GMT

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