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Re: Change in definition of RDF literals

From: Martin Duerst <duerst@w3.org>
Date: Wed, 21 May 2003 09:28:42 -0400
Message-Id: <4.2.0.58.J.20030521091927.073d63d8@localhost>
To: Graham Klyne <gk@ninebynine.org>, "Jeremy Carroll" <jjc@hplb.hpl.hp.com>
Cc: <w3c-rdfcore-wg@w3.org>

Overnight, I was thinking a bit more about the wider issues at hand.

It appeared to me that there are three different ways to have
a simple string in RDF:

<foo xml:lang=''>Hello World!</foo>
<foo xml:lang='' parseType='Literal'>Hello World!</foo>
<foo rdf:datatype='http://www.w3.org/2001/XMLSchema#string'>Hello World!</foo>

All three are plain strings without language, but they are
represented slightly differently in RDF.
What the recent decision of the RDF WG has done is that it has
said that the xml:lang='' in the second variant is unnecessary.
But this doesn't look like it has addressed the underlying problems.

Regards,    Martin.

At 18:50 03/05/19 +0100, Graham Klyne wrote:
>At 08:38 19/05/03 -0400, Martin Duerst wrote:
>>I think one way to see it is that the underlying problem is the use
>>of a datatype of rdf:XMLLiteral for parseType='Literal' is rather
>>artificial. When I read that for the first time, I thought that it
>>might be nice to allow XML Schema complex types there, which
>>would allow validation of the contents, and would bring simple
>>types and complex types closer together.
>>The alternative solution is to not treat parseType='Literal' as
>>a type at all, but as something separate, as a basic literal in
>>and by itself. One way to go would be to treat all literals as
>>being XML, with the simple case just having no markup. The
>>N-triples notation then would maybe just use some elements
>>of XML syntax, such as &amp; and &lt;. Just an idea.
>
>On reflection, I think this last idea is a logical step on from the 
>decision we reached last Friday, in that it removes the special-case 
>datatype, which I think is a further useful simplification.  I think we 
>were forced to consider XML literals separately from ordinary literals 
>when we were trying to accommodate the namespace issues, but having 
>dropped that idea I think distinguishing XML may be no longer needed.
>
>parseType="Literal" then becomes a pure syntactic device to prevent the 
>enclosed literal from being interpreted as RDF, which to my mind is far 
>closer to the form of literals that I understood to be presented in the 
>original RDF M&S.  Non-XML serializations of RDF simply don't have to be 
>aware of XML literals, which I think is a Good Thing.
>
>#g
>
>
>-------------------
>Graham Klyne
><GK@NineByNine.org>
>PGP: 0FAA 69FF C083 000B A2E9  A131 01B9 1C7A DBCA CB5E
Received on Wednesday, 21 May 2003 09:43:48 EDT

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