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Re: Does anyone like microdata?

From: Edward O'Connor <hober0@gmail.com>
Date: Mon, 29 Jun 2009 11:50:18 -0700
Message-ID: <3b31caf90906291150l4a9a5210kcdefc173f3bf81e8@mail.gmail.com>
To: Maciej Stachowiak <mjs@apple.com>
Cc: Ian Hickson <ian@hixie.ch>, Shelley Powers <shelleyp@burningbird.net>, public-html@w3.org
Hi,

Maciej Stachowiak wrote:

> Does anyone agree with the inclusion of the microdata section? In
> particular, does anyone think microdata is better than including no
> solutions to address the use cases at which it is aimed?

I do. I think the microdata attributes round out HTML's existing
extensibility points, so that HTML provides sufficient hooks for
distributed extensibility while avoiding any unnecessary complexity.
(HTML, of course, has many existing extensibility points. I think
microdata provide enough of the missing extensibility bits such that
we can close ISSUE-41 now.)

As background info, I'm a sometimes-participant in the microformats
community, and have been since its inception. While I don't speak for
the microformats community, that's the direction from which I'm viewing
HTML5's microdata features.

Microformats currently use the language extension mechanisms present in
HTML 4: @profile (de jure, anyway; in practice, microformats processors
don't rely on profile), @class, meta@name, @rel, and the like. As I've
said elsewhere[1]:

> Microformats are a great example of a community coming together and
> taking advantage of HTML's existing extensibility points[…]
> microformats thrive within the constraints of HTML's existing
> extensibility points.
>
> HTML5's microdata proposal isn't some kind of competing way to mark up
> data, it's a change to the underlying language extension mechanisms.
> In the future, when microformats are defined on top of HTML5[2], they
> will be able to take advantage of microdata attributes
> (@item, @itemprop, and the like), its unambiguous data extraction
> algorithm, as well as other new bits of HTML5 (e.g. the <time>
> element).

Jonas Sicking was looking for "feedback from people designing microdata-
like syntaxes (such as the microformat community)." I hope the above
helps.

Jonas wrote:
> However I definitely would like to see the Predefined vocabularies
> removed from the spec and instead let them fight on their own merits.
> I think they are completely independent to the rest of the spec and
> thus nothing would be lost by having them in their own spec.

My understanding is that the predefined vocabularies were included in
the HTML5 spec because they interact with other HTML5 features:
drag-and-drop, conversion of HTML into RDF/JSON/vCard/other formats,
etc. That said, I think these vocabularies could be (and perhaps should
be) usefully extracted from the spec.

In the case of the vCard, vEvent, and BibTeX vocabularies, their
specification in microdata resembles how I expect the hCard, hCalendar,
and citation microformats to look when reformulated for HTML5. Perhaps
these vocabularies could be extracted and work continued on them within
the microformats community, assuming willing editors can be found.

James Graham wrote:
> Compared to microformats I believe the HTML 5 microdata offers more
> consistent parsing rules (a single parser can unambiguously parse all
> microdata, allowing features such as automatic conversion to RDF) and
> cleaner seperation from the rest of the markup language.

Indeed.

Robin Berjon wrote:
> It certainly is an interesting extension point, enough that I'm
> looking into changing some of the XML formats I use to
> XHTML5+microdata.

Yes. As I said above, I believe microdata rounds out HTML's
extensibility points nicely, which should help with any efforts to
author reusable semantic HTML (such as microformats or poshformats[3]).


-- 
Edward O'Connor

1. http://edward.oconnor.cx/2009/05/microdata-microformats-and-rdf
2. http://microformats.org/wiki/html5
3. http://microformats.org/wiki/posh#poshformats
Received on Monday, 29 June 2009 18:56:59 UTC

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