W3C home > Mailing lists > Public > public-rdf-in-xhtml-tf@w3.org > September 2009

Re: PROPOSAL: Errata text to deal with the issue of predeclared 'xml' and 'xmlns' prefixes

From: Philip Taylor <pjt47@cam.ac.uk>
Date: Thu, 24 Sep 2009 21:45:36 +0100
Message-ID: <4ABBDA70.6070808@cam.ac.uk>
To: Shane McCarron <shane@aptest.com>
CC: "public-rdf-in-xhtml-tf.w3.org" <public-rdf-in-xhtml-tf@w3.org>
Shane McCarron wrote:
> [...] Unfortunately, this version of the RDFa Syntax 
> Recommendation is silent on whether these prefix mappings are required 
> to be included in the collection of URI mappings at the start of 
> processing.

Isn't it actually very explicit that they are not included? It defines 
the processing model algorithm with:

   "An initially empty list of [URI mapping]s, called the [local list of 
URI mappings]."

and a list that contains mappings for xml and xmlns at the start of 
processing is not initially empty.

Then the local list of URI mappings is never modified except via:

   "Next the [current element] is parsed for [URI mapping]s and these 
are added to the [local list of URI mappings]. [...] Mappings are 
provided by @xmlns. The value to be mapped is set by the XML namespace 
prefix, and the value to map is the value of the attribute—a URI."

so it will only add mappings that are explicitly declared in xmlns:* 
attributes in the document. So I can't see any way to interpret the spec 
that would allow xml and xmlns to be automatically bound.

Also, I remember it being mentioned several times on the lists that RDFa 
merely imports the namespace syntax from Namespaces in XML, and nothing 
else, and it could just as easily call the attribute e.g. 'banana' 
instead of 'xmlns'. That view seems to conflict with the idea that the 
default xml/xmlns mappings are imported too.

Philip Taylor
Received on Thursday, 24 September 2009 20:46:12 UTC

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