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[whatwg] Annotating structured data that HTML has no semantics for

From: Maciej Stachowiak <mjs@apple.com>
Date: Mon, 18 May 2009 06:23:05 -0700
Message-ID: <BECBC841-5373-41D4-94A6-E36BCBC09C76@apple.com>

On May 18, 2009, at 6:05 AM, Eduard Pascual wrote:

> On Mon, May 18, 2009 at 10:38 AM, Henri Sivonen <hsivonen at iki.fi>  
> wrote:
>> On May 14, 2009, at 23:52, Eduard Pascual wrote:
>>
>>> On Thu, May 14, 2009 at 3:54 PM, Philip Taylor <excors+whatwg at gmail.com 
>>> >
>>> wrote:
>>> It doesn't matter one syntax or another. But if a syntax already
>>> exists (RDFa), building a new syntax should be properly justified.
>>
>> It was at the start of this thread:
>> http://lists.whatwg.org/htdig.cgi/whatwg-whatwg.org/2009-May/019681.html
> Ian's initial message goes step by step through the creation of this
> new syntax; but does *not* mention at all *why* it was being created
> on the first place. The insight into the choices taken is indeed a
> good think, and I thank Ian for it; but he omitted to provide insight
> into the first choice taken: discarding the multiple options already
> available (not only Microformats and RDFa, but also other less
> discussed ones such as eRDF, EASE, etc).


I think Ian did explain why he discarded RDFa as an option.

In the email linked above, Ian Hickson wrote:
> Another solution we could consider is RDFa:
>
>      <section typeof="d:cat" xmlns:d="http://damowmow.com/">
>       <h1 property="d:name">Hedral</h1>
>       <p property="d:desc">Hedral is a male american domestic  
> shorthair,
>       with a fluffy black fur with white paws and belly.</p>
>       <img src="hedral.jpeg" alt="" title="Hedral, age 18 months"
>       class="photo" rel="d:img">
>      </section>
>
> This unfortunately also has a number of problems.
>
>  - it uses prefixes, which most authors simply do not understand, and
>    which many implementors end up getting wrong (e.g. SearchMonkey
>    hard-coded certain prefixes in its first implementation, Google's
>    handling of RDF blocks for license declarations is all done with
>    regular expressions instead of actually parsing the namespaces,  
> etc).
>    Even if implemented right, namespaces still lead to flaky
>    copy-and-paste behaviour.
>
>  - it sometimes uses rel="" and sometimes uses property="" and it's  
> hard
>    to know when to use one or the other.
>
>  - it introduces much more power than is necessary to solve this  
> problem.


I believe Microformats were discarded as a solution because the  
proposed use case was as follows:

> USE CASE: Annotate structured data that HTML has no semantics for,  
> and which nobody has annotated before, and may never again, for  
> private use or use in a small self-contained community.

But Microformats are only intended for widely used and generally  
agreed upon public vocabularies. The Microformats process is not  
applicable to private-use/small-community vocabularies. And  
Microformats define specific vocabularies, not a general way to add  
new kinds of semantic markup. I expect Microformats experts would  
agree with this assessment.


So I think it is clear why neither Microformats or RDFa were seen as  
suitable solutions to the use case, even if the matter was addressed  
somewhat briefly.


Regards,
Maciej
Received on Monday, 18 May 2009 06:23:05 UTC

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