Re: graph containing comprehensive set of ill-formed shapes

It is important for interoperability that SHACL Core implementations are
required to *not* silently produce different results on valid shapes graphs.
Instead they must be required to signal that they have been given a shapes
graph that they do not completely handle.

peter


On 04/21/2017 12:01 PM, Irene Polikoff wrote:
> But, of course, SHACL Core and SHACL-SPARQL implementations will produce different results. This is by design. 
> 
> SHACL Core processors do not support SHACL-SPARQL. By definition, a SHACL Core and a SHACL SPARQL processors are only interoperable for a subset of SHACL which is SHACL Core and sh:sparql is not in SHACL Core.
> 
>> On Apr 21, 2017, at 2:43 PM, Peter F. Patel-Schneider <pfpschneider@gmail.com> wrote:
>>
>> A SHACL implementation that silently ignores sh:sparql constructs produces an
>> interoperability nightmare.
>>
>> For example, such an implementation will produce no violations for the shape
>>  ex:sparql a sh:NodeShape ;
>>    sh:targetNode ex:i ;
>>    sh:sparql "SELECT ?this WHERE { }" .
>> A SHACL-SPARQL implementation will instead produce a violation.
>>
>> peter
>>
>>
>> On 04/21/2017 03:39 AM, Irene Polikoff wrote:
>>> Peter,
>>>
>>> If your implementation is SHACL Core only, how could SHACL-SPARQL constructs affect it? It would seem to me that the values in the sh:spraql triples would be no different to it than values in the ex:foo (or any user defined predicate) triples.
>>>
>>> Sent from my iPhone
>>>
>>>> On Apr 21, 2017, at 12:45 AM, Peter F. Patel-Schneider <pfpschneider@gmail.com> wrote:
>>>>
>>>> My alt-SHACL implementation does complete syntax checking, signalling whenever
>>>> in encounters a shape or path or list that is not correctly formed.  My
>>>> implementation has a strict mode that signals whenever the putative shapes
>>>> graph contains anything that violates any of the SHACL Core syntax rules or
>>>> contains a recursive shape or contains SHACL-SPARQL constructs that could
>>>> affect validation.  To test this checking I had put together an RDF graph
>>>> containing a comprehensive set of constructs that need to be checked.
>>>>
>>>> I just updated this graph, and the associated checking code, to incorporate
>>>> the numerous additional syntax rules that were added when the SHACL document
>>>> became a candidate recommendation.   I include the graph here.  It can be
>>>> turned into a comprehensive set of syntax test cases for SHACL Core by just
>>>> separating it into small graphs each containing one of the test shapes.
>>>>
>>>> The amount of code required to do complete syntax checking was quite modest.
>>>> Running my implementation over the graph was helpful in finding bugs such as
>>>> incorrect recursion checks in the path code.  I strongly recommend that every
>>>> SHACL implementation be run on every shape in this graph.
>>>>
>>>> Peter F. Patel-Schneider
>>>> Nuance Communications
>>>> <syntax.ttl>
>

Received on Friday, 21 April 2017 19:04:23 UTC