Re: shapes-ISSUE-103 (Syntax simplifications): Can we further simplify the syntax of some constraint types? [SHACL Spec]

I have no strong opinion. We could theoretically make the use of 
sh:PropertyConstraint illegal at sh:constraint. You should make a 
proposal if you believe this is important. I can see arguments going 
both ways. Even if we made these disjoint, it would still be possible to 
constrain properties at sh:constraint, e.g. using sh:and/sh:AndConstraint.

Holger


On 11/6/15 3:03 AM, Arthur Ryman wrote:
> Holger,
>
> Wouldn't it be more orthogonal if there was no relation between
> sh:constraint, sh:property, and sh:inverseProperty? Each of these
> properties has different semantics for what they apply their node
> constraints to.
>
> 1. sh:constraint applies node constraints directly to the singleton
> set that contains just the current focus node.
> 2. sh:property applies node constraints to the set of nodes that are
> objects of triples that have the current focus node as subject and the
> value of sh:predicate as the predicate.
> 3. sh:inverseProperty applies node constraints to the set of nodes
> that are subjects of triples that have the current focus node as
> object and the value of sh:predicate as the predicate.
>
> -- Arthur
>
> On Wed, Nov 4, 2015 at 6:32 PM, Holger Knublauch <holger@topquadrant.com> wrote:
>> On 11/5/2015 9:27, Peter F. Patel-Schneider wrote:
>>> On 11/04/2015 03:24 PM, Holger Knublauch wrote:
>>> [...]
>>>> This is correct, as long you add an rdf:type triple, which your example
>>>> didn't.
>>>>
>>>> The following would be legal:
>>>>
>>>> sh:constraint [
>>>>       a sh:PropertyConstraint ;
>>>>       sh:class ex:c ;
>>>>       sh:predicate ex:p
>>>> ]
>>>>
>>>> However, even then sh:PropertyConstraint cannot have sh:not, which is
>>>> limited
>>>> to sh:NodeConstraint.
>>>>
>>>> Holger
>>>>
>>> So
>>>
>>> sh:constraint [
>>>        a sh:PropertyConstraint ;
>>>        a sh:NodeConstraint ;
>>>        sh:class ex:c ;
>>>        sh:predicate ex:p;
>>>        sh:not [...]
>>>    ]
>>>
>>> is OK?
>>
>> Yes, although at evaluation time there is no relationship between the sh:not
>> and the property constraints. So this is not a case we would want to promote
>> or encourage.
>>
>> Holger
>>
>>

Received on Thursday, 5 November 2015 20:36:26 UTC