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Re: GUIDE: Dumb question re namespaces.

From: Jonathan Borden <jonathan@openhealth.org>
Date: Wed, 14 Aug 2002 13:12:44 -0400
Message-ID: <3D5A8F8B.2A54626A@openhealth.org>
To: Jos De_Roo <jos.deroo.jd@belgium.agfa.com>
CC: "Smith, Michael K" <michael.smith@eds.com>, www-webont-wg@w3.org

Jos De_Roo wrote:
> > Why are all of the RDF and DAML example namespace URIs suffixed with a
> '#'?
> well, not *all* of them...
> it was agendum 8 for RDF Core Teleconference 2002-08-09 (datatypes, # | /)
>   http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2002Aug/0090.html
> but it wasn't discussed at that telecon

Sigh, there are two answers:

1) from a practical point of view, when RDF converts an XML Qname to a
URI, the namespace URI and local name are merely appended to form a URI
reference. If an alphanumeric character is at the end of a namespace
URI, it will be unclear in the resulting (concatenated) URI which part
was from the namespace URI and which part was from the local-name,
making it impossible to recover the QName from the URI reference.

This is the essential problem with non-RDF QNames such as those that
identify XML Schema types e.g.

<foo:example rdf:about="http://example.org" 
  <xsd:string>an XML Schema string</xsd:string>

which parses according to RDF into:

<http://example.org> <http://www.w3.org/2001/XMLSchemastring> "10" .

as opposed to (the intended)

... <http://www.w3.org/2001/XMLSchema#string> "10" .


TimBL suggests that HTTP URIs ought only identify _documents_ whereas
such URIs _with_ a '#' can identify anything (see www-tag@w3.org for
details). Hence XML Namespaces, being abstract entities rather than
documents, ought have a '#'. This view is, however, controversial.

Received on Wednesday, 14 August 2002 13:17:18 UTC

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