- From: Karen Coyle <kcoyle@kcoyle.net>
- Date: Fri, 13 Feb 2015 16:29:17 -0800
- To: public-data-shapes-wg@w3.org
+1 and Thanks, Harold. - kc On 2/13/15 2:06 PM, Solbrig, Harold R. wrote: > Folks, > > Apologies for not catching the call for feedback below. I very much > like Hoger's suggestion, "Another option would be to define a compiler > from ShExC into LDOM RDF and back", as it would get us closer to our > (Mayo/CIMI's) primary goal — a formal definition of the /semantics/ of > RDF data shapes. If we can compile back and forth, we are (hopefully) > demonstrating semantic equivalence. The Mayo/CIMI goal is to arrive at: > > 1. A consistent set of semantics for the specification of Shape Expressions > 2. At least one grammar/syntax that can formally represent these semantics > > We (again – Mayo/CIMI) would hope that the grammar meets some of our > own goals in terms of succinctness, understandability and the like but > we will be able live with whatever comes out as long as it fulfills our > semantic / functional requirements. > > It is quite likely that we will end up using other representational > forms in some of our projects in any case (one of the representations > that we have waiting in the wings is UML). While it might be helpful to > have community buy in on those other forms, it isn't essential as long > as we can demonstrate that there is an isomorphism between our > representation and the (or "a") standard representational form. I see > uses for both ShExC and LDOM RDF and, as long as we can agree that they > are (or share) different representations for the same thing, then we > will be quite happy. > > Arguing about whether ShExC, LDOM RDF or some other representation is > the right way to go is, in my mind, kind of like arguing on the syntax > of Turtle vs RDF/XML without first agreeing on the underlying model of > RDF itself. The representations are essential, in the sense that it is > danged hard to talk about a model without having a succinct grammar to > do so, but we need to use a first approximation of some grammar to > discuss the model and, only then, to create final specification(s) for > various representational forms. > > I would propose that we declare at the outset that we want both ShExC > and LDOM RDF to be able to represent the same core semantics (I say > "core" because I wouldn't object to either or both of them having > additional but optional features that go beyond the core specification). > Lets use whatever formalism makes the most sense in a given context to > explain what a given constraint should do and, once we've arrived at > some sort of consensus, record the decision using formal logic. A final > step would be to adjust the designs of one or both languages so that we > know exactly what an expression means and how the two align. > > Harold Solbrig > Mayo Clinic > > > From: Holger Knublauch <holger@topquadrant.com > <mailto:holger@topquadrant.com>> > Date: Friday, February 13, 2015 at 3:30 PM > To: RDF Data Shapes Working Group <public-data-shapes-wg@w3.org > <mailto:public-data-shapes-wg@w3.org>> > Subject: Re: Two Standards ? > Resent-From: <public-data-shapes-wg@w3.org > <mailto:public-data-shapes-wg@w3.org>> > Resent-Date: Friday, February 13, 2015 at 3:30 PM > > The upcoming F2F meeting is supposed to deliver the general direction, > select editors and deliverables [1]. I don't think my proposal here is > premature at all. In fact it touches on the very fundamental questions > that Peter suggested we discuss too. > > Holger > > [1] https://www.w3.org/2014/data-shapes/wiki/F2F2#Objectives > > > On 2/14/15 7:03 AM, Michel Dumontier wrote: >> I think all this discussion premature and counter to the intended >> focus of this WG. Stay focused on delivering the promised outcomes. >> >> m. >> >> Michel Dumontier, PhD >> Associate Professor of Medicine (Biomedical Informatics) >> Stanford University >> http://dumontierlab.com >> >> On Fri, Feb 13, 2015 at 12:06 PM, Holger Knublauch >> <holger@topquadrant.com <mailto:holger@topquadrant.com>> wrote: >> >> My concern is not about personal preferences, but about >> language(s) that end users will actually want to use. We already >> struggle to understand shapes versus classes within the WG. The >> separation that I propose would allow us to write two different >> primers that will be consistent to understand and use. >> >> If the charter does not give us the possibility to define two >> standards, then this becomes a matter of packaging. One approach >> is to introduce a small Abstract Syntax for the commonality >> between LDOM and ShExC. This may include something like the Shape >> Selectors, but not in RDF but "abstract". Another option would be >> to define a compiler from ShExC into LDOM RDF and back (I had >> proposed that before [1] without getting feedback). Both concrete >> syntaxes could still have a similar name, if that helps with the >> standardization process. >> >> I also assume that WGs are still allowed to slightly diverge from >> the original Charter if they justify their reasons for doing so - >> at least that is what I was told when we wrote the original >> charter. I believe the discussions over the last half year (and >> potentially another half a year well into 2015) provide some of >> those reasons. Also, producing a Compact Syntax has been mentioned >> in the charter. >> >> Holger >> >> [1] >> https://lists.w3.org/Archives/Public/public-data-shapes-wg/2015Jan/0223.html >> >> >> >> >> >> On 2/14/15 5:07 AM, Arnaud Le Hors wrote: >>> I don't think there is evidence yet that a common solution can't >>> be found. Yesterday's strawpoll tells me there is hope we can >>> find some common ground to build on to produce a standard that we >>> can all live with. This may not be anyone's personal preference >>> but standards are typically not. >>> >>> It may be that eventually some will seek to define other >>> standards but this won't happen here. Our charter doesn't give us >>> that possibility. >>> -- >>> Arnaud Le Hors - Senior Technical Staff Member, Open Web >>> Technologies - IBM Software Group >>> >>> >>> >>> >>> From: Dean Allemang <dallemang@workingontologist.com> >>> <mailto:dallemang@workingontologist.com> >>> To: Holger Knublauch <holger@topquadrant.com> >>> <mailto:holger@topquadrant.com> >>> Cc: RDF Data Shapes Working Group <public-data-shapes-wg@w3.org> >>> <mailto:public-data-shapes-wg@w3.org> >>> Date: 02/12/2015 08:08 PM >>> Subject: Re: Two Standards ? >>> Sent by: deanallemang@gmail.com <mailto:deanallemang@gmail.com> >>> ------------------------------------------------------------------------ >>> >>> >>> >>> I have been talking about Shapes with my FIBO colleagues - we >>> continue to face the expressivity issues around OWL (role >>> intersections and friendly fire seem to come up a lot for us). >>> We are moving in to things like SPIN/SWRL, and/or FIBO-RIF(a >>> proposal that I worked on last July that moves everything into a >>> subset of RIF) to solve our expressivity issues. We are >>> currently going to do all of this in Informative Annexes (as >>> opposed to normative recommendations), because we don't (yet) >>> have a good standard in which to write these things. >>> >>> An expressive shapes language, based on SPARQL, would satisfy our >>> group's needs quite well. >>> >>> I wonder a bit about the relationship between the two languages >>> that Holger proposes - is it important that we be able to define >>> how a ShEx shape corresponds to an LDOM definition? Or are they >>> being used in completely different places? I guess if we take >>> the XSD/RelaxNG example, there needn't be a deterministic >>> relationship between them. >>> >>> Looking back, it seems to me that it would have been a good thing >>> if RELAX-NG had been done through the auspices of the W3C instead >>> of OASIS. As it stands now, it seems as if one has to choose >>> one's standard organization to support one's technology. If we >>> simply recognize that there could be two different perspectives >>> and develop both standards, we could actually provide coherent >>> (non-competitive) advice about when each one should be used. If >>> we don't, and the other perspective has an audience, we'll end up >>> seeing it pursued in some other organization. Ugh. >>> >>> >>> Prima facie, it would seem like we are doubling our work, but I >>> don't think that's the case. As Holger said, each group has done >>> enough work now to write up a coherent spec. It would actually >>> be *more* work to try to reconcile them into a single >>> Recommendation. >>> >>> >>> This situation seems to me to be a bit different from the >>> profiles of OWL, where we use the same words with different >>> constraints on their usage. Here, we are solving parallel >>> problems with different mechanisms. Making two standards, that >>> are well-informed by one another, seems like a good idea to me. >>> >>> >>> >>> Dean >>> >>> >>> >>> >>> >>> >>> On Thu, Feb 12, 2015 at 7:25 PM, Holger Knublauch >>> <_holger@topquadrant.com_ <mailto:holger@topquadrant.com>> wrote: >>> A random thought before the week end: >>> >>> Can this WG (please!) produce two separate standards? >>> >>> 1) An RDF vocabulary similar to the original LDOM proposal >>> 2) The ShEx Compact Syntax aiming at the data reuse scenarios >>> >>> We already have RDF Schema. We already have OWL. We would already >>> have a third language (LDOM or whatever). Why not have a forth >>> language? >>> >>> The situation in very similar to XML Schema vs. DTD. vs RELAX-NG. >>> They all solve similar problems, but from different perspectives. >>> >>> We are currently trying to mix different paradigms together and >>> risk producing something that nobody will be happy with. People >>> with OO background will wonder what the fuzz is about this >>> parallel structure called "Shapes", raising the implementation >>> costs and creating a mix of parallel semantic webs. And ShEx >>> people don't want to worry about the interactions of the various >>> triple models at all - instead have the ShExC files live outside >>> of the triple store. And that makes sense because even if you >>> introduce ldom:instanceShape to separate shapes from classes, >>> you'd still run into conflicts with other ShEx models that also >>> happen to use ldom:instanceShape. The only proper solution here >>> is to not have triples in the first place. >>> >>> Another constant source of conflict will be the role of SPARQL. >>> The ShEx camp seems to be more concerned about the balance of >>> expressivity and complexity, while the SPIN camp has plenty of >>> use cases where expressivity is the main concern. Furthermore, a >>> SPIN-like LDOM can more easily be combined with existing RDFS and >>> OWL ontologies, filling gaps in that space. >>> >>> We have a handful of ShEx supporters in the WG. I am sure they >>> could turn their Member Submission into a formal spec quite >>> rapidly. From an LDOM point of view we have plenty of stuff >>> already implemented, and I'd be happy to wrestle and collaborate >>> with anyone to flesh out the open details. The Requirements >>> document is already being split into "Property constraints" and >>> "Complex constraints", so both camps can harvest from the same >>> catalog of requirements. We can also share test cases and produce >>> a small document explaining how to map from one language to >>> another. But the aforementioned reasons and the endless >>> discussions over the last half a year provide plenty of arguments >>> that justify why the WG chose to create two languages. >>> >>> Why would this separation of deliverables not work? >>> >>> Thanks, >>> Holger >>> >>> >>> >> >> > -- Karen Coyle kcoyle@kcoyle.net http://kcoyle.net m: 1-510-435-8234 skype: kcoylenet/+1-510-984-3600
Received on Saturday, 14 February 2015 00:29:46 UTC