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Re: Subjects as Literals, [was Re: The Ordered List Ontology]

From: Tim Furche <tim@furche.net>
Date: Thu, 1 Jul 2010 00:20:40 +0100
Message-ID: <AANLkTindkPvdVUU2E8I9eXnC0uZGt9adAV3VynPD4H9T@mail.gmail.com>
To: Antoine Zimmermann <antoine.zimmermann@deri.org>
Cc: Peter Ansell <ansell.peter@gmail.com>, Toby Inkster <tai@g5n.co.uk>, Semantic Web <semantic-web@w3.org>
Strictly speaking your example can be represented in RDF/XML, though
certainly not in a pretty manner.

<rdf:Description xmlns:prefix-to-avoid-non-XML-characters="mailto:az@">
  <prefix-to-avoid-non-XML-characters:ex.com>blabla</prefix-to-avoid-non-XML-characters:ex.com>
</rdf:Description>

That works for all URLs where characters occur within the URL that are
not allowed in XML names. Except, if that character is the last.

E.g.:

_:x <http://example.com/> "blabla" .

can not be expressed in RDF/XML. The same with any other ending
character in a predicate URL that is not allowed in an XML name (e.g.,
:, @, #, ...)

Admittedly, quite an odd URL, but technically it's a correct URL and
thus an RDF statement that can not be represented in RDF/XML.

To be fair, all this is explained in 8 Serializing an RDF Graph to
RDF/XML of http://www.w3.org/TR/REC-rdf-syntax/.


On Thu, Jul 1, 2010 at 00:07, Antoine Zimmermann
<antoine.zimmermann@deri.org> wrote:
> Le 30/06/2010 23:50, Peter Ansell a écrit :
>>
>> On 1 July 2010 07:25, Toby Inkster<tai@g5n.co.uk>  wrote:
>>>
>>> On Wed, 30 Jun 2010 13:18:25 -0700
>>> Jeremy Carroll<jeremy@topquadrant.com>  wrote:
>>>
>>>> Here are the reasons I voted this way:
>>>>
>>>> - it will mess up RDF/XML
>>>
>>> No it won't - it will just mean that RDF/XML is only capable of
>>> representing a subset of RDF graphs. And guess what? That's already
>>> the case.
>>
>> Could you point me to an example of a valid RDF graph that RDF/XML
>> cannot represent? I have heard people say this before but I don't
>> remember ever seeing an example.
>
> Take this example:
>
> _:x <mailto:az@ex.com> _:x .
>
> mailto:az@ex.com is a valid URI but it cannot be used as an XML element or
> attribute. In RDF/XML, predicates of triples appear either as XML elements
> or as attributes, like this:
>
> <rdf:Description myPredicate="blabla"/>
>
> or
>
> <rdf:Description>
>   <myPredicate>blabla</myPredicate>
> </rdf:Description>
>
> but you cannot write:
>
> <rdf:Description mailto:az@ex.com="blabla"/>
>
> nor
>
> <rdf:Description>
>   <mailto:az@ex.com>blabla</mailto:az@ex.com>
> </rdf:Description>
>
> because it is malformed XML.
>
>
>
> AZ
>
>
>



-- 
Tim Furche
Received on Friday, 2 July 2010 09:12:39 UTC

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