Re: Core or Lite?

Arnaud,

I believe that SHACL 1.0 should not necessarily try to built-in too much. It
should have some set of pre-built constructs and a way for users to define
additional constructs. There should be a way for users to define such
³extensions² formally and to publish and exchange them.

Standing up a repository of such templates, would actually be a useful idea.
After a couple of years, SHACL 1.1 or 2.0 could standardize more as more
common patterns emerge.

I see this as very Semantic Web approach to the problem. With this, I would
not worry too much if 1.0 covered 80% or not. This, anyhow, varies across
different users. It is much better to get out there faster with some
pre-built set and a good mechanism for building more than to spend two or
three times more time trying to define just the right set ­ which is very
elusive because it depends on the context of use.

Irene

From:  Arnaud Le Hors <lehors@us.ibm.com>
Date:  Tuesday, March 24, 2015 at 1:12 PM
To:  Irene Polikoff <irene@topquadrant.com>
Cc:  <public-data-shapes-wg@w3.org>
Subject:  Re: Core or Lite?

Hi Irene,

Thank you for your input. What you're saying is actually very much in line
with the findings of the workshop. We can define a declarative way that will
address 80% of use cases and we need an extension mechanism to address the
remaining 20%.

Am I missing something?
--
Arnaud  Le Hors - Senior Technical Staff Member, Open Web Technologies - IBM
Software Group




From:       Irene Polikoff <irene@topquadrant.com>
To:       Arnaud Le Hors/Cupertino/IBM@IBMUS, <public-data-shapes-wg@w3.org>
Date:       03/24/2015 09:27 AM
Subject:       Re: Core or Lite?




Majority of our customers end up needing to write some SPARQL-based
templates for data validation and UI generation. The pre-built constructs
may cover 80% of their use cases, but 20% still remains. And for some the
pre-built constructs (and we ship a bit more than what is now in SHACL)
cover less than 50%. We try to look for commonality and gradually include
the most common ones as pre-built. But complete coverage is simply not
possible. Each customer has some uniqueness. Being able to formally define
their own templates has been pretty critical for these users. Some have
talked about creating template exchanges where they could share with others.

Over the last 10 years of working with customers that use RDF to stand up
enterprise solutions, we have been in direct communication with hundreds if
not thousands (some use our products without having any in depth
interactions with us). These customers span many different industries ­
financial services, pharma and health care, energy, manufacturing,
government and so on. I am not sure to what extent anyone else on the
working group has had a similar breadth and depth of experience across the
number of different customers, applications and industries.

Many of these users have running enterprise systems and their needs are
important. I believe the fact that the workshop did not receive this input
shouldn't matter at this point. We are providing it today. Further, this
working group has moved well beyond the information available during the
workshop by collecting requirements over the last 6 months. Is there any
reason we need to go back to the workshop when considering requirements?

Irene

From: Arnaud Le Hors <lehors@us.ibm.com <mailto:lehors@us.ibm.com> >
Date: Tuesday, March 24, 2015 at 11:51 AM
To: <public-data-shapes-wg@w3.org <mailto:public-data-shapes-wg@w3.org> >
Subject: Re: Core or Lite?
Resent-From: <public-data-shapes-wg@w3.org
<mailto:public-data-shapes-wg@w3.org> >
Resent-Date: Tue, 24 Mar 2015 15:57:35 +0000

I think we're touching on the very point of division in the group: whether
writing complex queries using SPARQL is the normal/common case or not. From
my point of view the workshop clearly didn't support that point of view and
this is why the charter is written the way it is.

Participants agreed that we should have a declarative mechanism a la OSLC
Resource Shapes and, in recognition of the fact that there is only so much
one can do that way, an extension mechanism should also be available to
address complex cases which can't be handled declaratively. Here is how the
report reads (http://www.w3.org/2012/12/rdf-val/report
<http://www.w3.org/2012/12/rdf-val/report> ):

There was consensus on the need for
1.        Declarative definition of the structure of a graph for validation
and description.
2.        Extensible to address specialized use cases.
3.        A mechanism to associate descriptions with data.

Note that this doesn't mean that the extension mechanism is any less
normative than the declarative one but it makes a difference as to whether
the extension mechanism is the center piece (or as Richard put it "the most
basic construct") or not.
--
Arnaud  Le Hors - Senior Technical Staff Member, Open Web Technologies - IBM
Software Group


Arthur Ryman <arthur.ryman@gmail.com <mailto:arthur.ryman@gmail.com> > wrote
on 03/24/2015 05:50:14 AM:

> From: Arthur Ryman <arthur.ryman@gmail.com <mailto:arthur.ryman@gmail.com> >
> To: Holger Knublauch <holger@topquadrant.com <mailto:holger@topquadrant.com> >
> Cc: "public-data-shapes-wg@w3.org <mailto:public-data-shapes-wg@w3.org> "
<public-data-shapes-wg@w3.org <mailto:public-data-shapes-wg@w3.org> >
> Date: 03/24/2015 05:51 AM
> Subject: Re: Core or Lite?
> 
> Holger,
> 
> All aspects of SHACL that are described by the spec are normal in the
> sense that they define compliant behavior. You seem to be implying
> that only Part 1 is normal. I don't understand what is gained by this
> use of the term "normal".
> 
> I'd also like to clarify that I think we only need one RDF namespace.
> Part 1 defines some of the terms and Part 2 defines the rest of the
> terms.
> 
> If we are going to use the term "normal", let's agree on the meaning.
> One meaning is say that the largest user group is the "normal" one. If
> that is the case then we have clear feedback that the majority of
> users will want a high-level vocabulary for expressing common
> constraints. A smaller, more advanced, set of users will write
> constraints in SPARQL, JS, ShEx, etc.
> 
> -- Arthur
> 
> 
> 
> 
> 
> On Tue, Mar 24, 2015 at 1:50 AM, Holger Knublauch
> <holger@topquadrant.com <mailto:holger@topquadrant.com> > wrote:
> > On 3/24/2015 15:17, Arnaud Le Hors wrote:
> >
> > Holger,
> > What would constitute the "extension mechanism" in your view then?
> >
> >
> > The macro facility could be regarded as an extension mechanism for the core
> > vocabulary. Another extension mechanism is the ability to use other
> > languages such as shx:javaScript. But writing complex queries (e.g. using
> > SPARQL) is not an extension mechanism. Also, using pre-defined macros from a
> > 3rd party template library is also not an extension. So the headline of that
> > Part 2 should reflect this differently. That was all I wanted to point out.
> >
> >
> > I have to point out that Arthur's suggestion happens to be very much in line
> > with what the charter calls for:
> >
> > An RDF vocabulary, such as Resource Shapes 2.0, for expressing these shapes
> > in RDF triples, so they can be stored, queried, analyzed, and manipulated
> > with normal RDF tools, with some extensibility mechanism for complex use
> > cases.
> >
> > I don't think it helps to ignore that and try to force people into
> > considering what was meant to be an "extensibility mechanism for complex use
> > cases" the "completely normal use of SHACL".
> >
> >
> > I stick to my statement that it is a completely normal use of SHACL to
> > include SPARQL queries. It is also completely normal for OWL DL users to
> > rely on features outside of OWL Lite. In the draft, SPARQL is part of the
> > official spec. For a large class of users, what you call the "extensibility
> > mechanism" will even be the main feature of SHACL. This includes people who
> > currently use OWL and just want to use SPARQL for the bits that OWL cannot
> > express. This is how TQ customers have operated for many years and is also
> > the least disruptive path to adoption if we want SHACL to succeed with
> > current semantic web people.
> >
> > What we have right now in the WG is that some people believe they don't
> > really need SPARQL support, and that the core features are sufficient for
> > most use cases. That's good for them, although not backed by much empirical
> > evidence. At this stage we have no idea which features will be most widely
> > used. Claiming that feature 1 is more important than feature 2  (and call
> > feature 2 just an "extension") is premature and makes it more difficult for
> > the supporters of feature 2 to get heard.
> >
> > The wording in the Charter was in retrospect unfortunate but it was
> > difficult to clarify all these nuances in a single short sub-sentence. Back
> > then I have been very clear that I will object to any attempts to
> > marginalize the SPARQL support, and I will continue to do this. I hope the
> > group respects the point of view of the SPARQL camp in the same way that we
> > all respect the point of view of those who don't need really SPARQL support.
> > My draft supports both view points.
> >
> > Regards,
> > Holger
> >
>