Re: On the inevitability of SPARQL/SPIN for SHAQL

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>> On 02/28/2015 01:51 AM, Jose Emilio Labra Gayo wrote:
> On Sat, Feb 28, 2015 at 1:54 AM, Peter F. Patel-Schneider 
> <pfpschneider@gmail.com <mailto:pfpschneider@gmail.com>> wrote:
> 
> I think that it is about time to accept the fact that SHAQL is going to
> be based on SPARQL and look a lot like SPIN.  This is not my preferred
> outcome from the working group, but I can live with it in the absence of
> anything better.
> 
> 
>> In my opinion, what we should do, is to clarify what are the roles of
>> SPARQL here and the relationship between SPARQL and SHACL.
> 
> Why do I say that SPARQL/SPIN is inevitable for SHAQL?  There is no
> other proposal that will satisfy the bulk of the members of the working
> group.  I myself would prefer something based on OWL Constraints, but
> there are many working group members who feel a need for features that
> are not part of the RDF model theory.
> 
> 
>> I think we should not throw in the towel now. In this email:
> 
>> https://lists.w3.org/Archives/Public/public-data-shapes-wg/2015Feb/0266.html
>
>>  You proposed a model-based semantics based on a simple language that
>> can be used as a first step towards a core language. I was reviewing it
>> and I think it is compatible with the axiomatic semantics of the same
>> subset of language features.

If this semantics is to be used as the, or even a, basis of SHACL, a
significant portion of the working group would have to endorse it.  I
haven't see any evidence that this is even a possibility.

It is possible that OWL constraints, or the new model-theoretic semantics
that I created, could become an ancillary part of SHACL.  OWL Constraints,
in particular, is known to be compatible with a SPARQL-based semantics for
SHACL.

> There are the various versions of Shape Expressions, but each of them has
> fatal problems.  The W3C Submission has a broken semantics and there ia
> no obvious way to fix it.  The algebraic version of Shape Expressions is
> too different from the other proposals and doesn't even work on RDF
> graphs.  The Resource Shape 2.0 W3C submission is only words.
> 
> 
>> It was said in another thread and during the meeting that most of the
>> people behind Shape Expressions and Resource Shapes are part of the WG
>> and I think we are all committed to define the new SHACL formalism. I
>> still think that we should keep working on to find the common features
>> that underlies all the proposals.

I don't see any common ground emerging.  I don't even see any significant
common ground between the various versions of Shape Expressions.

[...]

peter
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Received on Tuesday, 3 March 2015 02:51:53 UTC