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Wednesday, November 28, 2007

CURIE Syntax 1.0: A Syntax for Expressing Compact URIs

W3C announced the publication of an updated version of "CURIE Syntax
1.0." The document was produced by members of the W3C XHTML 2 Working
Group as part of the HTML Activity. Originally this document was based
upon work done in the definition of XHTML2, and work done by the
RDF-in-HTML task force, a joint task force of the Semantic Web Best
Practices and Deployment Working Group and XHTML 2 Working Group. It
is not yet stable, but has had extensive review and some use in other
W3C documents. It is being released in a separate, stand-alone
specification in order to speed its adoption and facilitiate its use
in various specifications. The aim of the document is to outline a
syntax for expressing URIs in a generic, abbreviated syntax. While it
has been produced in conjunction with the HTML Working Group, it is not
specifically targeted at use by XHTML Family Markup Languages. The
target audience for this document is Language designers, not the users
of those Languages. More and more languages are expressing URIs in XML
using QNames. Since QNames are invariably shorter than the URI that
they express, this is obviously a very useful device. The definition
of a QName insists on the use of valid XML element names, but an
increasingly common use of QNames is as a means to abbreviate URIs,
and unfortunately the two are in conflict with each other. This
specification addresses the problem by creating a new data type whose
purpose is specifically to allow for the abbreviation of URIs in
exactly this way. This type is called a "CURIE" or a "Compact URI",
and QNames are a subset of this. CURIEs can be used in exactly the
same way that QNames have been used in attribute values, with the
modification that the format of the strings after the colon are
looser. In all cases a parsed CURIE will produce an IRI. However,
the process of parsing involves substituting the value represented
by the prefix for the prefix itself, and then simply appending the
part after the colon. More Information

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