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xml:lang (non-)use-cases

From: Graham Klyne <GK@NineByNine.org>
Date: Tue, 24 Jul 2001 07:44:38 +0100
Message-Id: <5.1.0.14.2.20010724072059.00a5f2f0@joy.songbird.com>
To: RDF core WG <w3c-rdfcore-wg@w3.org>
 From the last teleconference, I was tasked to come up for use cases for 
RDF literals that were not expressed in any any language designated by 
xml:lang;  i.e. for which an xml:lang attribute is not meaningful.

These examples are taken from CC/PP and UAPROF:  one can argue about 
whether these are the best way to model the concepts described using RDF, 
and I might agree, but they do exist in real RDF applications so that 
argument would be moot:


1. UAPROF

The original RDF/XML document

  <?xml version="1.0"?>
  <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
           xmlns:ccpp="http://www.w3.org/2000/07/04-ccpp#"
           xmlns:uaprof="http://www.wapforum.org/UAPROF/ccppschema-20000405#">
    <rdf:Description rdf:about="http://example.org/HWDefault">
      <rdf:type rdf:resource="http://example.org/HardwarePlatform" />
      <uaprof:display>320x200</uaprof:display>
      <uaprof:memory>16Mb</uaprof:memory>
    </rdf:Description>
  </rdf:RDF>

Triples of the Data Model in N-Triples Format (Sub, Pred, Obj)

<http://example.org/HWDefault> 
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type> 
<http://example.org/HardwarePlatform> .
<http://example.org/HWDefault> 
<http://www.wapforum.org/UAPROF/ccppschema-20000405#display> "320x200" .
<http://example.org/HWDefault> 
<http://www.wapforum.org/UAPROF/ccppschema-20000405#memory> "16Mb" .


2. CC/PP using CONNEG-derived tags

The original RDF/XML document

  <?xml version="1.0"?>
  <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
           xmlns:ccpp="http://www.w3.org/2000/07/04-ccpp#"
           xmlns:client="http://www.w3.org/2000/07/04-ccpp-client#">
    <rdf:Description rdf:about="http://example.org/ClientCapability">
      <client:charset>us-en</client:charset>
      <client:pix-x>1024</client:pix-x>
      <client:color>mapped</client:color>
    </rdf:Description>
  </rdf:RDF>

Triples of the Data Model in N-Triples Format (Sub, Pred, Obj)

<http://example.org/ClientCapability> 
<http://www.w3.org/2000/07/04-ccpp-client#charset> "us-en" .
<http://example.org/ClientCapability> 
<http://www.w3.org/2000/07/04-ccpp-client#pix-x> "1024" .
<http://example.org/ClientCapability> 
<http://www.w3.org/2000/07/04-ccpp-client#color> "mapped" .


...

In each case, the value of the literal object is a sequence of characters 
intended to be interpreted by some computer program, not by a human 
reader.  As such, the value of an xml:lang attribute for these literals 
would be meaningless.

#g


------------
Graham Klyne
(GK@ACM.ORG)
Received on Tuesday, 24 July 2001 02:45:07 EDT

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