Re: Review of latest RDFa Core 1.1

On Mar 6, 2011, at 10:09 AM, Gregg Kellogg wrote:

[snip]

Section 6. CURIE Syntax Definition

Paragraph 3 describes the 'default prefix' mapping to be http://www.w3.org/1999/xhtml/vocab#. To me, this implies that the initial list of URI mappings (described in 7.5) contains such a mapping, however the text explicitly states that it is empty (or as defined in the RDFa Profile). Indeed, the XML RDFa Profile does contain this mapping, but what about host languages that don't use this profile? 4.3 XML+RDFa Document Conformance only applies to generic XML documents, and is integrated into XHTML+RDFa 1.1. Presumably, a host language could not include this definition, or any default profile. Should the language indicate that the initial set of uri mappings include XHV?


The default prefix mapping is very special.   It is the mapping that comes into play with there is a colon and a reference (e.g., :prev).  It is not possible to override this mapping.  All RDFa processors are required to support it.  The term 'default prefix' is unfortunate, but is historical and I don't feel like we can change it at this time.

So, to answer your question, no - I don't think that there is any need to define this mapping in the RDFa Profile.  Indeed, I don't think there is any WAY to define it.  And if there is, I think that is an error.  Since this is not meant to be overridable, there shouldn't be a way to define the mapping.  That way lies madness ;-)

Yes, I see that a prefix must match the NCName production, which precludes the empty string. I'll add a test for @prefix and @profile to ensure that these do not result in a change of the default prefix.

So, there is a test for this: Test 0180 checks to see that defining prefix to ":" changes the mapping. So, from what you're saying, this test should be marked "rejected" and replaced with a new test that ensure that it cannot change this mapping. My processor was not actually requiring that the prefix was an NCName, and allowed an empty string. How do other processors handle this?

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML+RDFa 1.1//EN" "http://www.w3.org/MarkUp/DTD/xhtml-rdfa-2.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
>
  <head>
    <title>Test 0180</title>
    <base href="http://example.org/"/>
  </head>
  <body>
  <div about ="#me" prefix=": http://xmlns.com/foaf/0.1/" >
      <p property=":name">Ivan Herman</p>
  </div>
  </body>
</html>

<http://example.org/#me> <http://xmlns.com/foaf/0.1/name> "Ivan Herman" .

Gregg

Received on Sunday, 6 March 2011 23:47:24 UTC