[whatwg] A Selector-based metadata proposal (was: Annotating structured data that HTML has no semantics for)

Eduard Pascual herenvardo at gmail.com
Sun May 17 04:36:03 PDT 2009

First of all, thanks for the time taken to review the document and to
post your feedback. I truly appreciate it.

On Sat, May 16, 2009 at 2:12 PM, Toby A Inkster <mail at tobyinkster.co.uk> wrote:
> In part 0.1 you include some HTML and some RDF triples that you'd like to
> mark up in the HTML and conclude that RDFa is incapable of doing that
> without adding extra wrapper elements.
> While adding redundant wrapper elements and empty elements is occasionally
> needed in RDFa (and from what I can tell, the microdata approach is even
> worse at this), the example you give doesn't require any.
I think I already stated this somewhere, but it never hurts to state
it again: as any human, I can make mistakes; and my knowledge about
RDF, RDFa, and even CSS, is definitely far from perfect. So, thanks
for your post that has actually improved it a little, with the
"revelation" that @property can take multiple values. My apologies for
that wrong example, then, I'll try to fix that part ASAP. Trying to
think about which cases would then require wrappers in RDFa, the only
situation I've come up with is when the value should be reused for
properties about different subjects. And, to my surprise, just
realized that CRDF in embedded form didn't handle those case neither!
So, my most sincere thanks for highlighting this, since you have
revealed a serious issue on CRDF that will get fixed on the next
iteration of the document (hopefully due for late tuesday or early

> Part 0.3 of your document claims that RDFa is designed for XHTML
> "exclusively". This is not the case - the designers of RDFa went out of
> their way to make its use feasible in *any* XML or XML-like language. SVG
> Tiny 1.2 includes the RDFa attributes, so RDFa can be used in SVG.
My apologies here for such a bad wording, although your reply confirms
the idea behind the wording: RDFa was part of the "the future is XML"
dream, thus not taking into propper account non-X HTML. Not to say
that it was the RDFa's fault, since that was a quite widespread belief
(I shared it myself for a long while). But RDFa's XMLish approach is
the root of many issues for tag-soup HTML; perfectly illustrated by
the ammount of controversy generated on these lists by the
"xmlns:prefix" syntax.
I'll make sure to change that wording to better describe the idea
behind it; and I'd like to thank you for highlighting the issue.

> Part 0.3 also states that "both Microformats and RDFa require the
> human-readable values to be reused as the machine-
> readable ones.". Actually, RDFa provides @content and @resource which,
> respectively, over-ride human-readable text and human-intended link targets.
Again, my limited knowledge of RDFa has betrayed me. This, added to
Microformats missuse of abbr as a workaround, means that the issue
itself doesn't exist, at least not as initially percevied. I'm not
sure whether I'll remove that one entirely, or just briefly mention on
the "Issues with Microformats" section, due to the accessibility
issues with the abbr approach.

> Lastly, and most seriously, CRDF doesn't seem to distinguish between
> literals and resources.
This is definitely an important issue, which Tab already made me aware
of. Fortunately, it's easy to fix; and Tab himself provided a possible
solution, which is very likely to be part of the next version of the

Until I add the fixes to the document, it's only left to reiterate my
thanks for your feedback.

Eduard Pascual

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