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Re: Official Response to ISSUE-128 from RDF Web Apps WG

From: Michael[tm] Smith <mike@w3.org>
Date: Mon, 27 Feb 2012 11:52:19 +0900
To: Manu Sporny <msporny@digitalbazaar.com>
Cc: RDFa WG <public-rdfa-wg@w3.org>
Message-ID: <20120227025217.GD278@sideshowbarker>
Thanks for the response.

Resolving this by adding a statement saying that the empty string is
allowed on all RDFa attributes is acceptable to me, but I think it needs to
be qualified in some way; specifically, I'd suggest this:

  "an empty string for the value of any RDFa attribute MUST be allowed as
  conforming unless a Host Language specifically disallows the empty string
  for a particular attribute"

I suggest this because the wording "an empty string for the value of any
RDFa attribute MUST be allowed as conforming" requires a Host Language to
always allow the empty string (or to word it differently, it prevents a
Host Language from disallowing the empty string).

This is not a hypothetical problem, because the HTML5 spec does actually
already disallow the empty string for the value of the "src" attribute on
any element, and for the value of the "href" attribute on <link>:

  http://dev.w3.org/html5/spec/media-elements.html#attr-media-src
  http://dev.w3.org/html5/spec/the-link-element.html#attr-link-href

The spec does that by defining a datatype called "valid non-empty URL
potentially surrounded by spaces":

  http://dev.w3.org/html5/spec/urls.html#valid-non-empty-url-potentially-surrounded-by-spaces

So if you keep the unqualified wording saying "an empty string for the
value of any RDFa attribute MUST be allowed as conforming", that would seem
to me to make HTML5 a non-conforming Host Language.

So I think you need to go with wording like, "an empty string for the value
of any RDFa attribute MUST be allowed as conforming unless a Host Language
specifically disallows the empty string for a particular attribute".

  --Mike

Manu Sporny <msporny@digitalbazaar.com>, 2012-02-26 15:25 -0500:
[...]
> Working Group Decision
> ----------------------
> 
> The Working Group had always intended that the empty string was valid
> for all RDFa attribute values and agreed to update the specification
> text to make this more explicit.
> 
> RESOLVED: For the purposes of conformance, an empty string for the value
> of any RDFa attribute MUST be allowed as conforming. (non-substantive)
> 
> http://www.w3.org/2010/02/rdfa/meetings/2012-02-23#resolution_6
> 
> Since the Working Group had always intended this to be the case, it is
> noted as a non-substantive change for the purposes of the W3C Process.
> 
> The group would also like to thank you for your fine work on the new
> HTML validator suite for W3C, which includes both RDFa 1.1 and RDFa Lite
> 1.1.
> 
> Feedback
> --------
> 
> Since this is an official Working Group response to your issue, we would
> appreciate it if you responded to this e-mail and let us know if the
> decision made by the group is acceptable to you as soon as possible.

-- 
Michael[tm] Smith http://people.w3.org/mike/+
Received on Monday, 27 February 2012 02:52:25 GMT

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