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Re: [LC] Official SVG Tiny Working Draft Comments from W3C RDF in XHTML Task Force (ISSUE-2100)

From: Doug Schepers <schepers@w3.org>
Date: Fri, 10 Oct 2008 12:37:01 -0400
Message-ID: <48EF84AD.1030001@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-

I've split the different issues up, to track them better, and I'll
respond to each separately.

Manu Sporny wrote (on 10/9/08 11:06 PM):
> @rel/@rev values do not necessarily need to be prefixed
> -------------------------------------------------------
> http://www.w3.org/TR/SVGMobile12/metadata.html#MetadataAttributes
> """
> When used with RDFa, the values for the 'rel' and 'rev' attributes must
> be a CURIE [RDFA] (i.e., a prefixed string, such as 'cc:license' to
> indicate a Creative Commons license), while the values may simply be
> from a set of specific keywords for Microformats. These formats may be
> used independently, or in combination if the keywords do not clash.
> """
> The @rel/@rev values in RDFa can either be a reserved word or a CURIE as
> defined in the RDFa Syntax document[2]. Perhaps the SVG Tiny document is
> authored to not support reserved words due to a mis-reading or
> mis-understanding of the current CURIE specification[3]? The current
> specification allows both prefixed and unprefixed "reference only" values:
> http://www.w3.org/TR/curie/#s_syntax
> """
> curie       :=   [ [ prefix ] ':' ] reference
> ...
> A host language MAY interpret a reference value that is not preceded by
> a prefix and a colon as being a member of a host-language defined set of
> reserved values. Such reserved values MUST translate into an IRI, just
> as with any other CURIE.
> """
> We urge the SVG WG to not limit CURIEs and provide a CURIE mechanism as
> defined by the CURIE specification. It would make the job of RDFa parser
> authors much easier as there are less special cases to consider when
> creating their parser. The current language in SVG Tiny requires all
> current RDFa parsers to strip out all reserved word processing in order
> to conform to SVG+RDFa, which would lead to two increasingly divergent
> types of RDFa parsers:
> 1. Parsers that parse SVG+RDFa 1.0.
> 2. Parsers that parse "XHTML+RDFa 1.0".
> The SVG Tiny document seems to insist that terms must be of the form
> "x:y", instead of also allowing things like "license" (note that there
> isn't a preceding colon before a reserved word).
> We are currently working on a method to specify reserved words that will
> not need preceding colons and the current language in SVG Tiny would
> prevent that method from being used in SVG Tiny.
> Please do one of the following:
> * Adopt the current RDFa/CURIE processing rules as-is.
> * Define a set of reserved words that should be used in SVG Tiny and
>   preserve the functionality provided in the CURIE Specification.
> * Do not rule out the ability to use non-colon-prefixed reserved words.

> [2] http://www.w3.org/TR/rdfa-syntax/#relValues
> [3] http://www.w3.org/TR/curie/

As you note in another email [1], I think that this is simply a matter
of poor wording in the spec.  I truly apologize for making you take
pains to correct my cruddy wording, which was not intended to be
controversial, and is most likely a case of late-night sloppiness.
Thanks for catching it.

I have reworded that section in an attempt to clarify what I meant, and
further to indicate that SVG doesn't impose restrictions on RDFa or any
other format. Please review the new wording and comment if it's still
not quite right. [2]

In fact, our approach is quite the opposite... we believe that SVG
should impose on the attributes the bare minimum of authoring and
processing restrictions, so that other formats can use them as befits
their own constraints, while still allowing them some meaningful
context.  It's a fine balance, but I hope we're getting closer to the
happy medium.

Please let us know promptly if this response does or does not meet
satisfy your comment.

[1] http://lists.w3.org/Archives/Public/www-svg/2008Oct/0060.html
[2] http://dev.w3.org/SVG/profiles/1.2T/publish/metadata.html

-Doug Schepers
W3C Team Contact, SVG and WebApps WGs
Received on Friday, 10 October 2008 16:37:10 UTC

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