W3C home > Mailing lists > Public > public-data-shapes-wg@w3.org > April 2016

Re: More wording

From: Peter F. Patel-Schneider <pfpschneider@gmail.com>
Date: Mon, 18 Apr 2016 09:40:24 -0700
To: kcoyle@kcoyle.net, "public-data-shapes-wg@w3.org" <public-data-shapes-wg@w3.org>
Message-ID: <57150DF8.3080809@gmail.com>
There may be some misunderstanding here.  Shapes in SHACL are IRIs or blank
nodes and come from RDF graphs that are to be considered as shapes graphs.
RDF graphs are generally not considered to be instances of classes.

SHACL documents should be clear that SHACL shapes are IRIs or blank nodes
and not graphs or sets of triples.



Here is some Turtle syntax for an RDF graph

@prefix ex: <http://example.com/> .
@prefix ex: <http://www.w3.org/ns/shacl#> .

ex:s1 a sh:Shape ;
  sh:scopeClass ex:Person ;
  ex:property [ a sh:PropertyConstraint ;
 	        ex:predicate ex:p1 ;
                ex:valueShape ex:s2 ] ;
  ex:constraint [ a sh:PropertyConstraint ;
                  ex:predicate ex:p2 ;
		  ex:valueShape [ a sh:Shape ;
		  		  ex:constraint [ a sh:NodeConstraint ;
		                                  sh:class ex:Student ] ] ] .
ex:s2 a sh:Shape ;
  sh:constraint [ a sh:NodeConstraint ;
  		  sh:nodeKind sh:IRI ] .

When treated as a shapes graph, an RDF graph that results from this Turtle
syntax has three shapes in it
1. http://example.com/s1
2. http://example.com/s2
3. the blank node that is allocated when matching
  	[ a sh:Shape ;
	  ex:constraint [ a sh:NodeConstraint ;
	  		  sh:class ex:Student ] ]

peter


On 04/18/2016 09:03 AM, Karen Coyle wrote:
> 2. Shapes
> 
> Is: "Shapes are instances of the class sh:Shape and define a group of
> constraints that a set of focus nodes can be validated against."
> 
> Suggest: "Shapes are graphs that are instances of the the class sh:Shape.
> Shapes define one or more focus nodes in a data graph and constraints on
> triples in those focus nodes. The triples in the focus nodes are validated
> against the constraints in the shape."
> 
> I also suggest that we define "shape" as "an RDF graph of type sh:Shape" and
> not use "shape graph" but always use "shape" since "shape graph" is redundant.
> 
> I can make this change if we have agreement on it. If I don't hear back I may
> make this definition an issue.
> 
> kc
Received on Monday, 18 April 2016 16:40:53 UTC

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