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Re: Expressing triples with special characters in URLs

From: Adam Souzis <adam-l@souzis.com>
Date: Fri, 02 Apr 2004 11:41:55 -0800
Message-ID: <406DC203.8040601@souzis.com>
To: Jeremy Carroll <jjc@hplb.hpl.hp.com>
Cc: Jakob <jakob.voss@s1999.tu-chemnitz.de>, www-rdf-interest@w3.org

Here's a rule (from RxPath) for mapping QNames to URIs that works around 
this "last URI reference char must end in a XML NameChar" limitation.  
Probably won't help your case but one could imagine a future version of 
RDF/XML adopting something similar if such a minor limitation warranted 
fixing.

RxPath needs such a rule since it must be able to generate a QName from 
any possible RDF URI ref. The rule is defined here:
http://rx4rdf.liminalzone.org/RxPathSpec#id148914988

Basically the rule is before concatenating the namespace URI and the 
local name of the QName remove one underscore from the local name if the 
local name consists only of one or more underscores.

With this rule you can split any URI to a namespace, XML name pair by 
appending an underscore to the XML name if the URI ends with either a 
undercore or a non-NameChar.

-- adam

Jeremy Carroll wrote:

>
> Jakob wrote:
>
>> Hi,
>>
>> As far as I do understand the way to express a triple in XML is
>>
>> <rdf:Description rdf:about="http://www.mydomain.com/my_subject.html">
>>   <predicates:my-predicate      
>> rdf:resource="http://www.mydomain.com/my_object.html"/>
>> </rdf:Description>
>>
>> Since characters of XML-Tagnames are more restricted than characters 
>> in URLs I
>> wonder how to express triples where the predicate URL contains special
>> characters like ':', '&' and '%'? Its not quite common but possible 
>> for some
>> nodes (especially in my application ;-)
>>
>> Thanks a lot,
>>   Jakob Voss
>>
>
> It's OK as long as the predicate ends in a NCName (e.g. a single letter)
>
> _:a http://example.org/x%20y&z "" .
>
> can be written
>
> <rdf:Description>
>  <eg:z xmlns:eg="http://example.org/x%20y&amp;"/>
> </rdf:Description>
>
> not pretty ... if you have a predicate that does not end in a NCName 
> e.g. it ends in a special character or %79 or then it is a known 
> limitation with RDF/XML that you can't serialize that.
>
> Jeremy
>
>
>
Received on Friday, 2 April 2004 14:41:41 GMT

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