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Re: CURIE syntax: prefix separator required or not?

From: Dan Connolly <connolly@w3.org>
Date: Mon, 08 Feb 2010 16:22:59 -0600
To: Shane McCarron <shane@aptest.com>
Cc: public-rdf-in-xhtml-tf <public-rdf-in-xhtml-tf@w3.org>
Message-ID: <1265667779.3812.877.camel@pav.lan>
On Mon, 2010-02-08 at 15:43 -0600, Shane McCarron wrote:
> 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.

Still, the wording "Since non-CURIE values MUST be ignored" is broken,
right? "Albert_Einstein" is not a non-CURIE value; it's a CURIE
value with no prefix.

Also, in the generic case, this text is broken, right?

   A CURIE is comprised of two components, a prefix and a reference.
   The prefix is separated from the reference by a colon (:).


> 
> 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? ;-)
> >
> >   
> 


-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
gpg D3C2 887B 0F92 6005 C541  0875 0F91 96DE 6E52 C29E
Received on Monday, 8 February 2010 22:23:02 GMT

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