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PROPOSAL: Errata text to clarify CURIE-related processing requirements

From: Shane McCarron <shane@aptest.com>
Date: Wed, 23 Sep 2009 12:10:06 -0500
Message-ID: <4ABA566E.2090904@aptest.com>
To: "public-rdf-in-xhtml-tf.w3.org" <public-rdf-in-xhtml-tf@w3.org>
Jeni and others have pointed out that the context in which CURIEs are 
evaluated can be hard to discern because the rules are complex, subtle, 
and distributed throughout the specification.  I propose the following 
errata text:

Rules for evaluating CURIEs and SafeCURIEs are defined throughout the 
Recommendation.  For the avoidance of doubt, these rules require at 
least the following:

   1. The set of prefix mappings to use when expanding CURIEs to IRIs is
      provided by the current in-scope prefix declarations of the
      element on which the CURIEs are found (see section 7 and section
      5.5 step 2).
   2. The URI to use when the 'default' prefix is referenced from a
      CURIE (e.g., ':next') is '|http://www.w3.org/1999/xhtml/vocab#'
      (see section 7). An RDFa Processor MUST expand CURIEs prefixed
      with only a colon using this prefix mapping.|
      ||
   3. There is no mapping defined when there is no prefix AND no colon
      specified (see section 7).  Therefore, an RDFa processor MUST NOT
      expand non-prefixed CURIEs (however, see reserved terms below).
   4. The prefix '_' is reserved and is used to refer to document-local
      blank nodes (bnodes) - see sections 5.4.5 and 7.  RDFa processors
      MUST ignore any declaration of a mapping for that prefix.
   5. The reserved terms (defined in section 9.3) are ONLY processed on
      the attributes rel and rev. All other attributes that take CURIEs
      or SafeCURIEs as values MUST NOT treat reserved words specially. 
      The datatype definitions are in section 9.1, and the attribute to
      datatype mappings are in section 9.2.
   6. Prefix declarations are subject to the syntactic restrictions
      defined in the Namespaces in XML Recommendation (see section 5.5
      step 2).  These restrictions include prohibiting the declaration
      of a prefix mapping for the special prefix 'xmlns' and limiting
      the declaration of the special prefix 'xml' to map to its
      pre-defined namespace URI (see the Namespaces in XML
      Recommendation, section 3). RDFa Processors MUST behave as if
      these restrictions are enforced.

Ben, can we please try to get this on the agenda for tomorrow?

Thanks!

-- 
Shane P. McCarron                          Phone: +1 763 786-8160 x120
Managing Director                            Fax: +1 763 786-8180
ApTest Minnesota                            Inet: shane@aptest.com
Received on Wednesday, 23 September 2009 17:10:50 GMT

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