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Re: [LC] Official SVG Tiny Working Draft Comments from W3C RDF in XHTML Task Force (ISSUE-2099)

From: Doug Schepers <schepers@w3.org>
Date: Fri, 10 Oct 2008 14:04:43 -0400
Message-ID: <48EF993B.2090907@w3.org>
To: Manu Sporny <msporny@digitalbazaar.com>
CC: SVG WG <www-svg@w3.org>, RDFa mailing list <public-rdf-in-xhtml-tf@w3.org>

Hi, Manu-

Manu Sporny wrote (on 10/9/08 11:06 PM):
> 
> Re-use of RDFa attributes should follow RDF in XHTML processing rules
> ---------------------------------------------------------------------
> 
> http://www.w3.org/TR/SVGMobile12/metadata.html#MetadataAttributes
> """
> SVG includes several attributes that may be placed on any element, for
> the use of attribute-based metadata formats. These include the 'class',
> 'role', 'rel', 'rev', 'about', 'content', 'datatype', 'property',
> 'resource', and 'typeof'  attributes. ***SVG makes no specific
> requirements about the values for these attributes, other than their
> particular value data types, such as a string or a space-separated lists
> of strings.*** Other specifications, such as RDFa [RDFA], Microformats
> [MF] patterns, or ARIA [ARIA] ontologies,
> """
> 
> The current text leaves far too much room for mis-use and abuse of the
> RDFa attributes. It would be a shame if authors were allowed to
> re-define how a non-RDFa parser may use those attributes in such a way
> as to directly conflict, or even worse, create ambiguity with regard to
> the current RDF in XHTML parser rules. The RDFa task force went to great
> lengths to ensure that the RDFa Syntax Processing[1] rules define clear
> behavior when RDFa is used in non-XHTML languages.
> 
> Please add text clearly stating that if one re-uses the RDFa attributes
> that they follow the same processing rules as outlined in the RDFa
> Syntax Processing Rules[1].
>
> [1] http://www.w3.org/TR/rdfa-syntax/#sec_5.5.

While the SVG WG does not wish to restrict use of these attributes
unduly, and hopes that they can be used productively and consistently by
other formats than RDFa (such as the evil Microformats, bane of many
metadaticians), we do sympathize with your desire that those attributes
not be hijacked and misused.  We strove to be consistent with RDFa in
the way we defined the attributes themselves [1] (though the
descriptions are not identical, since we felt the need to provide more
context and were asked to add distinction between those attributes and
others in SVG).

At the same time, we are reluctant to add a normative dependency on RDFa
(despite that specification's maturity) because we cannot rely upon
there being multiple interoperable SVG User Agents that currently
implement the RDFa processing rules.  We hope this will change, spurred
on by our inclusion of these attributes.

Therefore, we have struck a compromise position, adding wording that
recommends but does not mandate the use of the RDFa processing rules
(which we can do without imposing normative requirements on UAs) [2]:
[[
In order to maintain consistency and simplicity of implementation, and
prevent conflict or ambiguity of use, if an author or a non-RDFa format
reuses the 'about', 'content', 'datatype', 'property', 'resource', or
'typeof'  attributes, it is recommended that this is done in a manner
consistent with the RDFa Syntax Processing Rules [RDFA].
]]

We hope that this will satisfy your comment, but please let us know
promptly either way.


[1] http://dev.w3.org/SVG/profiles/1.2T/publish/struct.html#Core.attrib
[2]
http://dev.w3.org/SVG/profiles/1.2T/publish/metadata.html#MetadataAttributes

Regards-
-Doug
Received on Friday, 10 October 2008 18:05:35 GMT

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