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Re: FPWD Review Request: HTML+RDFa

From: Sam Ruby <rubys@intertwingly.net>
Date: Thu, 03 Sep 2009 14:05:14 -0400
Message-ID: <4AA0055A.1060503@intertwingly.net>
To: Mark Birbeck <mark.birbeck@webbackplane.com>
CC: Anne van Kesteren <annevk@opera.com>, Manu Sporny <msporny@digitalbazaar.com>, HTML WG <public-html@w3.org>, RDFa Developers <public-rdf-in-xhtml-tf@w3.org>
Mark Birbeck wrote:
> Hi Sam,
> 
> On Thu, Sep 3, 2009 at 3:53 PM, Sam Ruby<rubys@intertwingly.net> wrote:
>>> All that an RDFa parser needs to know is what the mapping is between
>>> some token and its full URI, and it really doesn't care whether the
>>> mechanism to do this is:
>>>
>>>  prefix="dc http://purl.org/dc/terms/"
>>>
>>> or:
>>>
>>>  prefix="dc=http://purl.org/dc/terms/"
>>>
>>> or:
>>>
>>>  prefix-dc="http://purl.org/dc/terms/"
>>>
>>> or:
>>>
>>>  xmlns:dc="http://purl.org/dc/terms/"
>> I'd like to suggest that we review the document[1] as presented.  I see
>> section 4.3 describes the fourth option, but I don't see the others being
>> proposed at all.
> 
> Right...because no-one is proposing the others in this document.
> 
> I was trying to explain why RDFa cannot be regarded as being "layered"
> on top of XML namespaces, because it doesn't actually require XML
> namespaces.
> 
> RDFa only requires a prefix mapping mechanism, and this could just as
> easily have been @xmlns-dc, @banana:dc, @samruby="dc=..." or something
> else entirely.
> 
> It just so happens that the W3C already used the xmlns-based attribute
> naming mechanism to create tokens, so we went with that.
> 
> But that is the beginning and end of RDFa's relationship with XML namespaces.
> 
> I don't know what else to do to explain this really simple point.

The "layering" concern is an equally simple point.  People who "layer" 
their applications on top of libraries (in other words: simply use such 
libraries) based on the same standards that you referenced will often 
have namespaces transparently "taken care of" for them.  And sometimes 
this will make their job harder.

I'm not suggesting that you change anything.  I'm just trying to explain 
the point that is being made.  Saying that RDFa could have chosen a 
different syntax misses that point.

The two possible resolutions I see here are:

(1) All things considered, we'd like to keep with the xmlns: syntax, 
warts and all.

(2) Upon further consideration, we'd like to change the syntax to avoid 
these problems.

> Regards,
> 
> Mark

- Sam Ruby
Received on Thursday, 3 September 2009 18:05:56 UTC

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