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Re: ISSUE-137 (including XML includes)

From: Jim Hendler <hendler@cs.rpi.edu>
Date: Fri, 12 Sep 2008 17:42:32 -0400
Cc: "Alan Ruttenberg" <alanruttenberg@gmail.com>, "W3C OWL Working Group" <public-owl-wg@w3.org>
Message-Id: <C166AD85-5914-42B3-84F0-36B2EDD817A3@cs.rpi.edu>
To: Bijan Parsia <bparsia@cs.man.ac.uk>

Interestingly enough, I find myself agreeing with large parts of what  
both Alan and Bijan are saying, even though they are disagreeing -  
rather than replying point to point, let me see if I can express where  
I think the issue may lie
  Bijan says, and I agree, that the RDF/XML syntax is the normative  
exchange syntax for OWL, that Xinclude is a standard and deployed,  
therefor putting Xinclude in the RDF/XML makes sense
  Alan says, and I agree, that if we just put in Xinclude as an XML  
directive (i.e. qua XML as it were) then we have the problem that  
there's nothing in the "OWL" per se that makes it clear the inclusion  
happens (i.e. unlike owl:imports, where there's something that however  
you serialize, you must serialize).  He also pointed out earlier (or  
maybe I am just inferring it from what he said) that the Xinclude spec  
is not that easy to understand, so it would take some extra work to  
document

  I'm not sure I see a solution, but my instinct is that if we worked  
at it we could find a solution where either the OWL ontology includes  
the XML within some declaration (so the graph itself woudl have some  
indication what is going on for other serializations to use) or that  
the XInclude definition could include an unparsed entity (or perhaps a  
notation or such) that the other serializations would be able to pick  
up on
  Can one of you folks who really understand this stuff say whether  
either of those is possible?
   -JH
p.s. Seems to me this would be a perfect place for the macro facility  
that was discussed sometime back - this somehow became issue 140,  
which isn't quite the same, but maybe the solution to that and this  
are similar somehow?


[1] http://www.w3.org/TR/xinclude/#unparsed-entities



On Sep 12, 2008, at 5:24 PM, Bijan Parsia wrote:

>
> On Sep 12, 2008, at 9:37 PM, Alan Ruttenberg wrote:
>
>> On Fri, Sep 12, 2008 at 4:07 PM, Bijan Parsia  
>> <bparsia@cs.man.ac.uk> wrote:
>>> On Sep 12, 2008, at 8:57 PM, Alan Ruttenberg wrote:
>>
>>>> An inclusion directive could be
>>>> expressed as an RDF triple, and the OWL documentation could specify
>>>> how it should be interpreted (i.e. by including the triples  
>>>> resulting
>>>> from parsing the included document).
>>>
>>> Which is a change to the other serializations. They now have a  
>>> triple that
>>> they have to interpret specially. Not just at the reasoner level,  
>>> but at the
>>> parsing level.
>>
>> No they don't. The inclusion directive would be interpreted by the  
>> OWL
>> processor, not by the RDF parser.
>
> Fair enough, although it introduces yet more syntax triples. We  
> already gave up some features for the sake of minimizing the  
> vocabulary. I would much prefer to have object and data properties  
> back if we intend to reopen that debate.
>
> Introducing things at the RDF level has lots of ramifications  
> including on OWL Full.
>
>>> Indeed, why should we impose a triple on them?
>>
>> It's their job to carry triples.
>
> ? The point is that serializations may prefer not to treat this as a  
> triple level matter.
>
>>> Turtle might prefer to add an @directive instead. N3 might prefer  
>>> to use their own builtin.
>>
>> I don't see how this affects what we need to do.
>
> We don't *need* to do what you would like us to do, so in that  
> sense, we agree that my point doesn't affect what we *need* to do.
>
> Other RDF serializations use non-triple constructs for various  
> syntax level features. Your approach precludes that.
>
> But ok, I withdraw my incoherence charge. There is a design that, in  
> some sense, will work across all RDF serializations if we are  
> willing to impose more stuff at the RDF level. However, it's a  
> design with several inherent issues even before we get to the rest  
> of the points I raised.
>
> Cheers,
> Bijan.
>

"If we knew what we were doing, it wouldn't be called research, would  
it?." - Albert Einstein

Prof James Hendler				http://www.cs.rpi.edu/~hendler
Tetherless World Constellation Chair
Computer Science Dept
Rensselaer Polytechnic Institute, Troy NY 12180
Received on Friday, 12 September 2008 21:43:25 UTC

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