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Re: GRDDL

From: Charles McCathieNevile <chaals@opera.com>
Date: Wed, 06 Aug 2008 22:01:10 +0200
To: "Henri Sivonen" <hsivonen@iki.fi>
Cc: "public-html@w3.org" <public-html@w3.org>
Message-ID: <op.ufhdv8bcwxe0ny@widsith.local>

On Wed, 06 Aug 2008 11:11:18 +0200, Henri Sivonen <hsivonen@iki.fi> wrote:

> On Aug 6, 2008, at 11:56, Julian Reschke wrote:
>
>>> ...
>>>>> I'm not sure if abusing HTML is the right characterization, but the  
>>>>> GRDDL setup violates the The Rule of Least Power TAG Finding.
>>>>> http://www.w3.org/2001/tag/doc/leastPower
>>>>
>>>> I'm not sure how using XSLT 1.0 violates that finding (please  
>>>> elaborate);
>>> XSLT is in a more powerful language category than (scriptless) HTML or  
>>> any of the notations for RDF triples.
>> > ...
>>
>> That's true. But how do you use RDF triples or scriptless HTML to  
>> extract RDF out of (X)HTML?
>
> You do this:
>> - Document the mapping between the host language and RDF, do not touch  
>> the host language, and have transformers for each of the languages,  
>> triggered by contenttype/doctype/xmlnamespace.

No, that doesn't work unless you also have a centralised authority  
creating the vocabulary. In the real web it is more common to us HTML with  
certain classes (or something equivalent such as word or PDF documents  
with certain formatting conventions). Since each user creates their own  
set of conventions, you don't have scalability. The Microformats approach  
is OK if we wanted to ask Tantek to decide what information we actually  
need to encode, but it turns out that large numbers of people have never  
heard of him, don't speak any language he speaks, don't see why they  
should have to talk to anyone else to make a private convention, and so  
this approach misses a lot of use cases that GRDDL deals with.

It ain't perfect, but it works, it meets a lot of use cases, it is based  
on existing widely-deployed technology, and it doesn't interrupt much of  
what people do. That seems a reasonable basis for saying OK, this isn't so  
bad.

(Having a way to make GRDDL work for HTML as well as XHTML would be nice.  
Given that in practice it could be done by passing the HTML through some  
well-known transform like an HTML5 parser that serialised to XHTML, I  
don't see that as a showstopper in practice. Also, most people who want to  
use RDF actually already know how to produce real XHTML if they need it,  
so that is a somewhat theoretical as opposed to real problem).

cheers

Chaals

-- 
Charles McCathieNevile  Opera Software, Standards Group
     je parle français -- hablo español -- jeg lærer norsk
http://my.opera.com/chaals   Try Opera 9.5: http://www.opera.com
Received on Wednesday, 6 August 2008 20:01:38 GMT

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