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Re: CURIE syntax: prefix separator required or not?

From: Shane McCarron <shane@aptest.com>
Date: Mon, 08 Feb 2010 15:43:09 -0600
Message-ID: <4B70856D.9020408@aptest.com>
To: Dan Connolly <connolly@w3.org>
CC: public-rdf-in-xhtml-tf <public-rdf-in-xhtml-tf@w3.org>
Both.  The CURIE spec is generic.  However, if you look just SLIGHTLY 
further in section 7 you will see:

In RDFa these values are defined as follows:

    * the *set of mappings from prefixes to URIs* is provided by the
      current in-scope prefix declarations of the [current element
      <http://www.w3.org/TR/rdfa-syntax/#T_current_element>] during parsing;
    * the *mapping to use with the default prefix* is the current
      default prefix mapping;
    * the *mapping to use when there is no prefix* is not defined, which
      effectively prohibits the use of CURIEs that do not contain a colon;
    * the *mapping to use with the '_' prefix*, is not explicitly
      stated, but since it is used to generate [bnode
      <http://www.w3.org/TR/rdfa-syntax/#T_bnode>]s, its implementation
      needs to be compatible with the RDF definition.

In other words, while the generic CURIE syntax permits no prefix, in 
RDFa that is not permitted.

Hope this helps.

Dan Connolly wrote:
> My quick-n-dirty implementation of CURIEs failed test 0091,
> so now I'm looking in detail, but I'm getting different
> signals from different parts of the spec:
> In 5.4.3.
> http://www.w3.org/TR/rdfa-syntax/#s_convertingcurietouri
> we see:
> [[
> Since non-CURIE values MUST be ignored, the following value in @about
> would not set a new subject, since the CURIE has no prefix separator.
> <div about="[Albert_Einstein]">
>   ...
> </div>
> ]]
> but section 7. CURIE Syntax Definition
> http://www.w3.org/TR/rdfa-syntax/#s_curies
> specifies that "Albert_Einstein" *is* a CURIE:
>   curie       :=   [ [ prefix ] ':' ] reference
> It even gives an example with no prefix separator:
>  * a mapping to use with the default prefix (for example, :p);
>  * a mapping to use when there is no prefix (for example, p);
> Meanwhile, there's this text just above the CURIE grammar
> and those two examples, which contradicts them:
>   A CURIE is comprised of two components, a prefix and a reference.
>   The prefix is separated from the reference by a colon (:).
> Which parts of the spec are right? ;-)

Shane P. McCarron                          Phone: +1 763 786-8160 x120
Managing Director                            Fax: +1 763 786-8180
ApTest Minnesota                            Inet: shane@aptest.com
Received on Monday, 8 February 2010 21:43:54 GMT

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