Re: Question about directValueType

On 9/25/2015 7:02, Solbrig, Harold R. wrote:
> Holger,
>
> Is the second sentence under sh:directValueType,  "The values of 
> |sh:directValueType| must be classes (instances of |rdfs:Class|)." 
> intended to be advice to people writing SHACL schemas or is it 
> intended to impose a requirement on the SHACL engine itself (e.g.  The 
> engine MUST raise an error if the target of sh:directValueType cannot 
> be confirmed to be an instance of rdfs:Class or something similar)?   
> If it is the latter, is it the data graph, the shapes graph or both 
> that are used to make this determination?

I believe such checking should be left to schema-level constraint 
checking, i.e. validation of the shapes graph itself. With the current 
Turtle file, the sh:valueClass of sh:directValueType is rdfs:Class and 
the system would flag such errors if the user has requested this kind of 
validation. However, at run-time such tests should not happen because it 
would be extra overhead and furthermore the class may only be defined as 
an rdfs:Class in the shapes graph. I am not sure if this distinction 
needs to be made clearer in the spec.

Holger