Re: “SHACL Minus SPARQL”

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Yes, I mean closed shapes, i.e., all triples in a graph (or around a node)
have to be somehow consumed by the shape.

I don't think that your idea of constructing the matched triples will work
in the presence of disjunction, at least without considerable code embedded
into the SPARQL engine.

peter


On 03/04/2015 06:37 AM, Richard Cyganiak wrote:
> 
>> On 3 Mar 2015, at 21:49, Peter F. Patel-Schneider
>> <pfpschneider@gmail.com> wrote:
>> 
>> I would like to see the core of a proposal for something that would
>> support "SHACL minus SPARQL" as well as the core of a proposal for
>> "SHACL plus SPARQL".
>> 
>> I think that I could fairly easily put together a proposal for most of
>> the former, but I am puzzled as to how to handle recursion and closure,
>> so I would like to see how a proponent of this approach would handle
>> recursion or closure.
> 
> By closure, do you mean “closed shapes” as described here? 
> https://www.w3.org/2014/data-shapes/wiki/Requirements#Expressivity:_Closed_Shapes
>
>  I’m not sure that this can be easily supported.
> 
> One way to do it might be to attach a second bit of SPARQL to each “macro
> definition”/“shape node”. That bit of SPARQL would CONSTRUCT the triples
> that are considered to be “covered” by a successful “macro”/“shape”
> evaluation. A SHACL processor would collect all those triples, and if any
> triples in the input RDF graph under consideration are not among those
> “covered”, then the closedness constraint is violated.
> 
> Personally I’m not fully convinced that this requirement is a good idea
> and necessary for SHACL 1.0, and there are many cases where I don’t know
> what the desired behaviour would be. I’d be quite comfortable with
> postponing this to a future version of SHACL.
> 
> My thoughts on recursion are too muddled to be of much help.
> 
> Best, Richard
> 
> 
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Received on Wednesday, 4 March 2015 15:21:58 UTC