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

Re: More wording

From: Arnaud Le Hors <lehors@us.ibm.com>
Date: Tue, 19 Apr 2016 10:01:31 -0700
Message-Id: <201604191701.u3JH1coS026168@d01av03.pok.ibm.com>
To: kcoyle@kcoyle.net
Cc: "public-data-shapes-wg@w3.org" <public-data-shapes-wg@w3.org>
Karen,

Since we're using github the best way to propose changes is to make 
changes to your own fork and submit a Pull Request the editors can then 
use to accept and merge in the changes.

If you're not familiar with github here is some help:

There are different ways to do this but one simple way is to go to the 
github page: 
https://github.com/w3c/data-shapes/blob/gh-pages/shacl/index.html
Click the "edit this file" button on the right (the little pen), make your 
changes, and instead of committing directly select "Create a new branch 
for this commit and start a pull request. " at the bottom of the page.

Thank you for doing this.
--
Arnaud  Le Hors - Senior Technical Staff Member, Open Web Technologies - 
IBM Cloud


Karen Coyle <kcoyle@kcoyle.net> wrote on 04/19/2016 09:13:45 AM:

> From: Karen Coyle <kcoyle@kcoyle.net>
> To: "Peter F. Patel-Schneider" <pfpschneider@gmail.com>, "public-
> data-shapes-wg@w3.org" <public-data-shapes-wg@w3.org>
> Date: 04/19/2016 09:15 AM
> Subject: Re: More wording
> 
> Thanks, Peter. I see places in the spec where shapes are given agency in 

> odd ways:
> 
> "2.1.1 Node scopes (sh:scopeNode)
> 
> Shapes define node scopes with the sh:scopeNode predicate"
> 
> I would be more comfortable with:
> 
> "The scope of a shape is defined with (?by?) the sh:scopeNode 
predicate."
> 
> Also, I find places where it isn't clear whether a statement is about 
> the shape graph or the data graph, such as:
> 
> 2.1
> "Node scopes define a specific RDF node as scope."
> 
> The RDF node in this case is a node in the data graph,* but that may not 

> be clear to the reader.
> 
> Also, in some places I see "shape" and in others "Shape", and I believe 
> these are referring to the same thing, so one form should be chosen.
> 
> Again, I'd like to see editorial changes of this nature made, but am 
> unclear how to coordinate with the current editors.
> 
> kc
> * Yes, the data graph can be a SHACL document. That doesn't change this.
> 
> On 4/18/16 1:19 PM, Peter F. Patel-Schneider wrote:
> > Yeah, I can see how that might be confusing.  You have to think that 
the
> > constraints of a shape are those that are (somehow) connected, or 
close, to
> > the shape node, which is not what one might think of if one was making 
an
> > analogy to programming languages or even SPARQL.
> >
> > Your suggested wording looks promising to me.
> >
> > peter
> >
> >
> > On 04/18/2016 01:11 PM, Karen Coyle wrote:
> >> OK, thanks, Peter. That truly wasn't clear, so I'll read further to 
see if
> >> this definition is followed in the text.
> >>
> >> But as an example, to me, the definition does not fit with the 
statement:
> >> "SHACL groups descriptive information and constraints that apply to a 
given
> >> data node into shapes. This document defines what it means for anRDF 
graph,
> >> referred to as the "data graph", to conform to a graph containing 
SHACL
> >> shapes, referred to as the "shapes graph"."
> >>
> >> I have trouble with "groups ... constraints ... into shapes" if a
> shape is an
> >> IRI/bnode. That is what made me think that shapes were intended 
> to be graphs,
> >> not things (graphs being groups of 1 or more triples). (You wouldn't 
say:
> >> "groups names into Persons".) Perhaps:
> >>
> >> "A shape is an instance of the class sh:Shape, either an IRI or a
> blank node.
> >> The descriptive information and constraints that apply to a givendata 
node
> >> are defined as the properties of a shape. A set of shapes that 
defines
> >> validation rules for a data graph (?or a portion of a data 
> graph?) is called a
> >> 'shapes graph'. A shapes graph consists of one or more shapes."
> >>
> >> Closer?
> >>
> >> kc
> >>
> >> On 4/18/16 9:40 AM, Peter F. Patel-Schneider wrote:
> >>> 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 
classsh: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
> >>>
> >>
> >
> 
> -- 
> Karen Coyle
> kcoyle@kcoyle.net http://kcoyle.net
> m: 1-510-435-8234
> skype: kcoylenet/+1-510-984-3600
> 
Received on Tuesday, 19 April 2016 17:02:12 UTC

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