Re: on the turtle serialization of SHACL

If the spec overrules the Turtle document, then I don't see how the Turtle
document can be considered to be normative and I don't even see any utility in
referring to the document at all.

However, I don't think that that is what you are saying.   You appear to be
saying that if this document contains something like
sh:Shape rdfs:subClassOf sh:PropertyConstraint .
then even if this is not stated anywhere in the SHACL document every shape is
also a property constraint in SHACL and all SHACL processors MUST treat them
as such, i.e., all SHACL processors MUST signal a syntax error on shapes
graphs like

se:s1 rdf:type sh:Shape ;
 sh:targetNode ex:n1 ;
 sh:class ex:c1 .

However only certain aspects of the Turtle document will have this kind of
effect.  As you say, rdfs:domain and rdfs:range portions won't do anything.
How then are they normative?

Further, it is the document itself that is being stated to be normative.  If
changing namespace prefixes doesn't change anything then it seems to be more
that the intent is not that the document is normative but that some RDF graph
has some normative intent.

So:

ISSUE:  The intent and effects of the Turtle document are unclear.


peter




On 12/13/2016 04:32 PM, Holger Knublauch wrote:
> The idea is that the existing TTL file is consistent with what is written in
> the main spec. If there are errors, I welcome bug reports. If we are unsure,
> we could add a statement along the lines of "the spec wins if the TTL file
> contradicts".
> 
> But overall this TTL file has a similar impact as any other file that may be
> imported into a shapes graph. So if someone adds a triple that makes
> sh:PropertyConstraint rdfs:subClassOf sh:Shape, and SHACL is defined to look
> for all SHACL instances of sh:Shape, then an engine will also treat those
> property constraints as shapes. SHACL doesn't do RDFS inferencing, so
> rdfs:domain has no impact unless the shapes graph has RDFS activated (which is
> outside of SHACL's concern). Changing namespace prefixes has no impact on
> behavior, changing sh:prefix triples would.
> 
> Holger
> 
> 
> On 14/12/2016 9:50, Peter F. Patel-Schneider wrote:
>> The current version of the SHACL document contains "The Turtle serialization
>> of the SHACL vocabulary is part of the normative specification. However, the
>> values of rdfs:label and rdfs:comment in that file are not normative.",
>> pointing to a Turtle document available on the web.
>>
>> In what sense is this document normative?
>>
>> Would removing the line "rdfs:subClassOf sh:Constraint ;" from the part of
>> the document about sh:Shape change anything about SHACL?  Would adding
>> "sh:PropertyConstraint rdfs:subClassOf sh:Shape." somewhere to the document
>> change anything about SHACL?  Would removing "rdfs:domain sh:Shape ;" from
>> the part of the document about sh:property change anything aobut SHACL?
>> Would changing "owl:" to "rowl:" throughout the document change anything
>> about SHACL?  Would changing the document in any way change SHACL?
>>
>>
>> Peter F. Patel-Schneider
>> Nuance Communications
>>
> 
>

Received on Wednesday, 14 December 2016 01:17:57 UTC