Re: Comments on 'precedural approaches'

From: Emmanuel Pietriga <>
Date: Tue, 26 Apr 2005 13:37:54 +0200

Danny Ayers wrote:
> Apologies for the interjection, but I feel obliged to throw in my 2
> cents, a bit of devil's advocacy.

Hello Danny,

Don't apologize! As far as I am concerned your 2 cents are very welcome,
though I disagree on this particular RDF/XML+XSLT issue.

>>Yes it can. But at what cost? The complexity is so huge... Again, that's
>>why I believe the RDF/XML+XSLT approach to be conceptually wrong.
> I'd personally be very reluctant to use a phrase as strong as
> conceptually wrong. This approach can work conceptually, although is
> usually outrageously difficult and is an inappropriate approach in the
> general case for the reasons you cite. But it can be done, which is
> demonstrated by the SemanticPlanet RDF/XML to NTriples stylesheet [1]

Yes, it can be done. But have you seen the complexity of this
stylesheet? It is 300+ lines long! Just to get an N-Triple
representation of RDF/XML. So I see this as a demonstration that this
approach is too difficult to really be considered for reasonably complex
RDF processing.

The fact that something is possible does not make it conceptually valid.
  I still think it is a conceptually defective approach.

>>My point is that it is not just a question of processing graphs or trees
>>with the right tools, it is also a question of how the data is
>>structured and represented. When presenting people with the RDF/XML tree
>>representation of a model, you force them to build a mental
>>representation of the RDF/XML tree and to map/convert it to what it
>>actually "means" at the more abstract (purely) RDF level. This is a hard
>>mental operation which requires a lot of *unnecessary* cognitive effort.
>>Here, it is more the HCI research scientist part of myself who talks,
>>but I believe this to be something that should be taken into account.
> I don't disagree, and like everyone around these parts have run into
> people with serious misapprehensions derived from the RDF/XML tree
> representation. Ok, RDF/XML+XSLT is certainly not a good approach to
> RDF in the general case. But I also think it would be a mistake to go
> too far in the opposite direction, and imply that you can't do
> anything useful with this approach. This may lead to another
> misapprehension, that RDF and XML technologies are somehow mutually
> exclusive.

I am not saying that you cannot achieve anything useful with such an
approach, or that people who do it are doing bad things. Far from it.
But still, I keep thinking that it is not a good thing to consider
RDF/XML+XSLT as the general way of processing RDF. That's because you
are "reasoning" on a serialization of the model, not on the model
itself. And *this* is not a good thing for the reasons explained before.

But you are right when you say that we should not go too far in the
other direction and make it look like RDF has nothing to do with XML.

Emmanuel Pietriga
INRIA Futurs - Projet In Situ    tel : +33 1 69 15 34 66
Bat 490, Université Paris-Sud    fax : +33 1 69 15 65 86
91405 ORSAY Cedex  
Received on Tue Apr 26 2005 - 11:38:56 EDT

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