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Re: QName to URI reference

From: Brian McBride <bwm@hplb.hpl.hp.com>
Date: Fri, 09 Mar 2001 13:24:35 +0000
Message-ID: <3AA8D993.ED3BC3DC@hplb.hpl.hp.com>
To: Jonathan Borden <jborden@mediaone.net>
CC: www-rdf-comments@w3.org
Jonathan,

Thank you for sending this issue which has been recorded as
http://www.w3.org/2000/03/rdf-tracking/#rdfms-qname-uri-mapping.

This will appear when the issue tracking document is next published to
the W3 site.

Brian


Jonathan Borden wrote:
> 
> Mapping namespace qualified element names to URIs
> 
> REC: insert '#' between namespace URI and local name when namespace URI ends
> in alphanumeric.
> 
> The current convention of concatenating a namespace URI reference and local
> name to convert a QName to URI reference is inconsistent with common usage
> of QNames
> 
> For example in XML Schema the QName: "xsd:unsignedInt" is used to refer to
> the simple datatype "unsigned integer". This corresponds to the fragment:
> 
> <simpleType name="unsignedInt" id="unsignedInt" ...>
> 
> within the document resolved from the URI:
> http://www.w3.org/2000/10/XMLSchema which is bound to the "xsd" prefix.
> 
> This simpleType definition is referenced by the URI reference:
> 
> http://www.w3.org/2000/10/XMLSchema#unsignedInt
> 
> however the RDF convention would produce
> http://www.w3.org/2000/10/XMLSchemaunsignedInt
> 
> It is not acceptable for RDF and XML Schema (among others) to have different
> conventions for naming the same concepts/resources.
> 
> A proposal:
> 
> It is necessary to map namespace qualified element names (QNames) to URIs
> for a variety of purposes but particularly in RDF. The RDF Model and Syntax
> specification directs this mapping to occur via concatenation of the
> namespace URI with the local name. This is acceptable when the namespace URI
> does not end with a character which cannot be used to begin an element name
> (an NCName) i.e. a Letter or '_', because the first non Letter or '_'
> encountered from the end of the URI can be used to delimit the namespace URI
> from the element name. Yet when the URI ends in a Letter or '_', several
> URI, NCName pairs may map to the same concatenated URI.
> 
> It is proposed for namespace URIs that when a namespace URI ends in a Letter
> or '_' that a '#' be inserted between the namespace URI and the element tag
> name to create the resultant URI. When such a URI is resolvable to a
> resource of media type text/html or text/xml, the fragment identifier
> resolves to an identifier of the element name. When the document is of type
> text/html, the identifier might point to a section which describes the
> element. When the document is of type text/xml (or application/xml) and the
> base document contains an RDF Schema, the identifier is expected to point to
> the Property or Class definition for the element name.
> 
> Jonathan Borden
> The Open Healthcare Group
> http://www.openhealth.org
Received on Friday, 9 March 2001 08:56:03 GMT

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