Re: comments on SHACL 3 March editors draft

Regarding filter shapes.
Another attempt is to provide the following definition in section 2:

A node can either conform or not conform to a shape. A node conforms to a
shape when for every scope, filter and constraint in a shape
 - the node is in scope, conforms to the filter shapes and satisfy the
constraint
 - the node is in scope but does not satisfy the filter shapes or
 - the node is not in scope.

this does not impose any order even for scopes but maybe I miss something
or needs some refinement (help welcome).

Regarding the remaining "first..then" in the spec.
I didn't put any effort in section 2.2 yet but if they are spread even
outside of 2.2 we should better create an issue to keep track of this (for
filter shapes)

Regarding the  "IF ... THEN" for filter shapes again, iirc they were
suggested by Arthur and we had a resolution on them for issue-49.

if there are other unnecessary ordering constructs we'd better create
separate issues, this thread is getting too big


On Tue, Mar 15, 2016 at 8:11 PM, Peter F. Patel-Schneider <
pfpschneider@gmail.com> wrote:

> I don't think that this solves the problem.
>
> Spread around the document is wording like "first... then" or other
> ordering
> constructs.  It may be that these ordering constructs change the result or
> it
> may be that all they do is specify a particular sequence of execution.  The
> problem with leaving them in without closely examining them is that it is
> very
> hard to know which is which.  Instead of a statement saying that order only
> matters when some little bit of the document has something where it does
> matter, the document should be written in a way that order doesn't matter
> unless it the ordering is necessary.
>
> If the specification for SHACL was pure SPARQL then this would not matter
> so
> much, but the specification for SHACL includes non-SPARQL stuff and some of
> this non-SPARQL stuff looks very procedural.  Thus a lot of care needs to
> be
> taken to ensure that no little thing deep down in the specification is some
> place where order changes the results.
>
> peter
>
> PS:  I'm not sure which figure is in play here.  If it is the UML-like
> figure
> then I don't see that it has any utility and it should go.
>
>
> On 03/15/2016 10:36 AM, Dimitris Kontokostas wrote:
> > Peter, can you check if this commit overcomes the ordering issue?
> >
> https://github.com/w3c/data-shapes/commit/9edef4c82a7f6480d0c45e3e34656c7f93f1dfa5
> >
> > Would you prefer to delete the figure completely? It that case I would
> delete
> > that last two lines of the commit too
> >
> >
> > On Mon, Mar 7, 2016 at 6:32 PM, Peter F. Patel-Schneider
> > <pfpschneider@gmail.com <mailto:pfpschneider@gmail.com>> wrote:
> >
> >     On 03/06/2016 08:46 PM, Holger Knublauch wrote:
> >     [...]
> >
> >     > On 7/03/2016 6:59, Peter F. Patel-Schneider wrote:
> >
> >     [...]
> >
> >     .2 Filters
> >
> >     >> A SHACL processor might not begin by validating filters.  It
> might instead
> >     >> look at all in-scope nodes and only later remove those that don't
> pass the
> >     >> filters.  The document makes this illegal but it might be useful
> if the
> >     >> filter shape is expensive to compute and few violations are
> expected.
> >     >
> >     > I believe this is already covered by stating that SHACL engines
> can produce
> >     > additional validation results, see discussion above.
> >
> >     This is not about validation results.  It is about order of
> execution.  The
> >     document states:
> >
> >     When a SHACL processor validates a focus node against a shape, it
> begins by
> >     validating any filters associated with the shape via sh:filterShape.
> >
> >     This is too procedural.
> >
> >     peter
> >
> >
> >
> >
> >
> > --
> > Dimitris Kontokostas
> > Department of Computer Science, University of Leipzig & DBpedia
> Association
> > Projects: http://dbpedia.org, http://rdfunit.aksw.org,
> > http://http://aligned-project.eu <http://aligned-project.eu/>
> > Homepage:http://aksw.org/DimitrisKontokostas
> > Research Group: AKSW/KILT http://aksw.org/Groups/KILT
> >
>
>


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