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Re: RDF-ISSUE-5 (Graph Literals): Should we define Graph Literal datatypes? [RDF Graphs]

From: Andy Seaborne <andy.seaborne@epimorphics.com>
Date: Sun, 06 Mar 2011 14:54:16 +0000
Message-ID: <4D73A018.3010603@epimorphics.com>
To: Steve Harris <steve.harris@garlik.com>
CC: Ivan Herman <ivan@w3.org>, Richard Cyganiak <richard@cyganiak.de>, RDF Working Group WG <public-rdf-wg@w3.org>


On 06/03/11 09:10, Steve Harris wrote:
> On 2011-03-06, at 08:23, Ivan Herman wrote:
>> On Mar 6, 2011, at 24:03 , Steve Harris wrote:
>>
>>> On 2011-03-05, at 14:49, Richard Cyganiak wrote:
>>>
>>>> On 4 Mar 2011, at 21:59, RDF Working Group Issue Tracker
>>>> wrote:
>>>>> RDF-ISSUE-5 (Graph Literals): Should we define Graph Literal
>>>>> datatypes? [RDF Graphs]
>>>>
>>>> Anyone could trivially define such datatypes. And once that is
>>>> done, tool vendors could easily add support for them.
>>>>
>>>> Given the relative ease of doing this, if there was actual user
>>>> demand for such datatypes, then surely someone would have
>>>> already defined them, and they would have seen some adoption.
>>>>
>>>> It is my strong belief that standardization efforts should
>>>> focus on codifying existing practice and not invent new
>>>> speculative things.
>>>
>>> Absolutely.
>>>
>>> rdf:XMLLiteral is kind of in this space, and no one really uses
>>> that, let alone an RDF version.
>>
>> Interestingly, AFAIK Drupal 7 uses XML Literals and that means,
>> potentially, millions of Web pages with RDFa encoding thereof...
>> Much that I do not like them...
>
> Ah, I stand corrected. That's unfortunate.

The rules for RDF XML Literals are very strict (to ensure that 
equivalence can be done by string equality).  The requirement to put 
attributes in sorted name order ,for example, means that placing GML 
fragments in RDF as RDF XML literals dones not work by simply adding the 
GML string.  This catches people out.

A weaker form of RDF XML literal might be better: the lexical space is 
less constrained but the value space is exclusive Canonical XML.

	Andy
Received on Sunday, 6 March 2011 14:54:57 UTC

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