Was: Should we define Graph Literal datatypes?


I was actually wondering whether there should not be a cleanup action/issue on XML Literals, namely their equality rules. There is a mess in my mind compared to different canonicalization algorithms, and I also wonder whether the references are still o.k. I know you have dived into this much more than I did...


On Mar 6, 2011, at 15:54 , Andy Seaborne wrote:

> 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

Ivan Herman, W3C Semantic Web Activity Lead
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Received on Monday, 7 March 2011 05:49:22 UTC