Re: shapes-ISSUE-220 (what is a shape): defining shapes in a shapes graph [SHACL - Core]

I am sure this can be resolved quickly in the next meeting, the reason I
decided to track this with the tracker was that it is related to issue-221.
Simplifying the hierarchy will make it easier to identify shapes as well

My proposal is to provide a normative definition and not an informative.

On Thu, Jan 26, 2017 at 2:44 AM, Holger Knublauch <holger@topquadrant.com>
wrote:

> As also discussed yesterday, I have added a paragraph right after the
> definition of "shape" in 2.1 explaining how this definition relates to
> well-formed shapes. This paragraph also links to a new section on "Finding
> Shapes in a Graph" with the patterns that can be used to distinguish shapes
> from other nodes.
>
> Note that these are informative because they are only required by a
> (hypothetical) group of applications such as UI tools, each of which may
> have different rules. For example some tools may rely on targets but others
> call shapes directly, by other means. Validation (which is our focus in the
> spec) does not need a formal definition of these rules, and making them a
> formal requirement invites new challenges on corner cases. So why
> complicate things further.
>
> https://github.com/w3c/data-shapes/commit/b2e47ae36f77cbcbd5
> 38f0ac5d04958149ff5fcd
>
> Corrections or additions are welcome.
>
> I hope this addresses this ticket.
>
> Holger
>
>
>
> On 26/01/2017 8:15, RDF Data Shapes Working Group Issue Tracker wrote:
>
>> shapes-ISSUE-220 (what is a shape): defining shapes in a shapes graph
>> [SHACL - Core]
>>
>> http://www.w3.org/2014/data-shapes/track/issues/220
>>
>> Raised by: Dimitris Kontokostas
>> On product: SHACL - Core
>>
>> The current editor's draft (as of today) defines the following:
>>
>>   - A shape is an IRI or blank node in the shapes graph.
>>   - sh:Shape is the SHACL superclass of those two shape types in the
>> SHACL vocabulary. Its subclasses sh:NodeShape and sh:PropertyShape can be
>> used to represent node and property shapes, respectively.
>>   - A node shape is a shape in the shapes graph that is not the subject
>> of a triple with sh:path as its predicate.
>>   - A property shape must be the subject of a triple that has sh:path as
>> its predicate. A node that has more than one value for sh:path is
>> ill-formed. Each value of sh:path must be a well-formed SHACL property path.
>>
>> with the current definition, every non-literal node in a shapes graph is
>> a shape. if a node has a value for sh:path the node is a property shape and
>> all other nodes are node shapes.
>> This provides no standardised way of identifying the shapes in a shapes
>> graph.
>>
>> The recent editors draft as well as the latest WD (as of August 14th) had
>> this well defined. The new spec introduced by Holger removed this
>> definition.
>>
>>
>>
>>
>
>


-- 
Dimitris Kontokostas
Department of Computer Science, University of Leipzig & DBpedia Association
Projects: http://dbpedia.org, http://rdfunit.aksw.org,
http://aligned-project.eu
Homepage: http://aksw.org/DimitrisKontokostas
Research Group: AKSW/KILT http://aksw.org/Groups/KILT