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Re: RDF/XML/Internet Collisons, Process (was Moving on)

From: Simon St.Laurent <simonstl@simonstl.com>
Date: Wed, 31 May 2000 16:04:24 -0400
Message-Id: <200005312002.QAA15899@hesketh.net>
To: <xml-uri@w3.org>
[I've stripped out material relevant to W3C process rather than this
particular discussion of the interaction between XML and RDF, moving it to
a Chaos, Process thread.  Yet more threads may appear if I can find time,
but we'll see.]

At 01:04 PM 5/31/00 -0400, Tim Berners-Lee wrote:
TBL1>What do we do, for example, when the RDF group has a 
TBL1>commitment from the XML community, and then in a public list 
TBL1>does not feel any responsibility to uphold that?
>>
SSL>This sounds like you're feeling hurt.  Could you explain what that
SSL>'commitment from the XML community' means - I don't think the XML
community
SSL>was ever asked per se to commit to RDF, and I don't quite understand your
SSL>complaint.
>
>Let me give you a filtered history to illustrate the 
>specific point. The RDF group were asked to use XML 
>as a serialization language to promote consistency 
>and re-use. They did though many would have preferred 
>S-expressions.

Okay, so the RDF WG decided to use XML...

[Also, the RDF spec doesn't make a strong commitment to XML.  From the
Introduction:
RDF>It is also important to understand that this 
RDF>XML syntax is only one possible syntax for 
RDF>RDF and that alternate ways to represent 
RDF>the same RDF data model may emerge. 
]

TBL>The RDF design needed its building blocks to be first 
TBL>class objects, which then translated into a need for 
TBL>element types to be first class objects. This feature 
TBL>was seen by XML folks as being an imporant general 
TBL>tool and so was - like atomic datatypes - something 
TBL>the RDF people were happy to be generalized into the 
TBL>XML layer. So the XML folks did it and the result was 
TBL>Namespaces.  It was weird in parts, but it was accepted 
TBL>as it seemd to do the trick, even though some say RDF's 
TBL>use of it looks weird.  Now when later there is a 
TBL>suggestion that  actually namespaces (and therefore 
TBL>XML elements, and therefore RDF properties) are not 
TBL>first class objects, then the connection is under threat.

That rosy 'filtered history' is contentious at best, though I don't know
how many participants will be excited about challenging it in a public
forum.  Still, even apart from that contentiousness, I see no 'commitment
from the XML community' here, just a willingness to use a tool for one
purpose (naming) that another community could reuse for their purposes.

TBL>Within the W3C system in principle there are coordination 
TBL>groups and charters and inter-group dependencies which you 
TBL>can fall back on and which sometimes aren't done very well 
TBL>but in principle show that there is a commitment from all 
TBL>involved to work together.  It is still difficult within 
TBL>the consortium structure which was set up specifically by 
TBL>people who wanted to solve this problem.

So it seems that the only clear extent of said commitment is that XML and
RDF were developed within the same organizational framework.

SSL>In general, the W3C might do well to 'sell' RDF more 
SSL>strongly, rather than hoping the larger XML and Web 
SSL>communities will develop interest on their own.  That 
SSL>might mean reconsidering RDF and making it more approachable,
SSL>among other possibilities.
>
TBL>I agree RDF needs better explanations and materials. 
TBL>As always it is really diffucult to know how to spend 
TBL>limited resources. I am not sure we don't *need* to 
TBL>sell everyone on RDF.  

I'm not sure selling everyone on RDF is necessary, as lots of folks don't
need RDF, or believe that to be the case, anyway.  On the other hand, it's
difficult to find sympathy for claims that XML must change in order to
accomodate RDF when RDF is barely known.

>Many projects are now getting on board. There is, true,  
>a danger that new projects will miss RDF and end up with 
>a messy data model as a result, but it quite easy to use 
>XSL to suck RDF out of XML documents which have a good 
>underlying model. Most people involved in RDF are 
>developing it and it takes tome to evangelize something. 
>I think an RDF primer would be useful. Also, like XML, 
>there are calls for a simplification down to the bare 
>minimum for a core - but a lot of people just building 
>code on top of what is there.

It sounds very much like XML's situation, overall - I just don't see the
same kind of enthusiasm for RDF in the outside world.  (I've tried to talk
publishers into RDF books, and consistently get back "What?" So far, a
chapter's all I've managed to get through.  Now I'm booked for the rest of
2000, with no RDF in sight.)

SSL>RDF's core community is still quite small, and while it overlaps with the
SSL>XML community, there are many members of the wider XML implementation
SSL>community who have never even heard of RDF, much less attempted to read
the
SSL>specifications or develop software.
>
>Is that a long term problem? Maybe many people should 
>wait until there are more tools, and applications with 
>RDF support built in.  The mainstream long term data 
>and metadata storage folks such as the libraries are 
>on board but they have been for a long time.

I'd agree that many people should wait, but there was very little of that
waiting in the XML community, which has grown much more rapidly and
developed more of its own tools.  (Len Bullard claimed at one point that
Microsoft's embrace of XML was the cause of that, but having worked
extensively with Microsoft's early tools I'm inclined to disagree.)

TBL>One neat thing about using URIs as the flexibility 
TBL>point is that the XML community does *not* have to 
TBL>commit to or understand RDF. Once Namespaces are first 
TBL>class objects then the URI concept is the main thing 
TBL>connecting the two, so apart from sharing the "first 
TBL>class object" idea XML and RDF can be developed in parallel.

I don't think it's yet been made clear that XML (apart from RDF) gains
anything but additional complexity from making Namespaces into 'first class
objects'.  The only gains appear to be on the RDF side.

I've suggested repeatedly that RDF would do better to 'bless' namespaces as
URIs (and first class objects if you like) within RDF, rather than imposing
such an obligation on XML processors.

TBL>This is much more practical and scalable than 
TBL>requiring them to be in lockstep.

Perhaps from your viewpoint, but I think a large number of people have made
clear that the vision you are presenting comes with a hefty and
disagreeable pricetag, and that the cost/benefit ratio is less than charming.

Simon St.Laurent
XML Elements of Style / XML: A Primer, 2nd Ed.
Building XML Applications
Inside XML DTDs: Scientific and Technical
Cookies / Sharing Bandwidth
http://www.simonstl.com
Received on Wednesday, 31 May 2000 16:02:16 UTC

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