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Re: Shapes/ShEx or the worrying issue of yet another syntax and lack of validated vision.

From: Peter F. Patel-Schneider <pfpschneider@gmail.com>
Date: Sun, 20 Jul 2014 02:05:03 -0700
Message-ID: <53CB863F.5000706@gmail.com>
To: Eric Prud'hommeaux <eric@w3.org>, Evren Sirin <evren@clarkparsia.com>
CC: Sandro Hawke <sandro@w3.org>, Kendall Clark <kendall@clarkparsia.com>, Jerven Bolleman <jerven.bolleman@isb-sib.ch>, Dimitris Kontokostas <kontokostas@informatik.uni-leipzig.de>, Jose Emilio Labra Gayo <jelabra@gmail.com>, "Dam, Jesse van" <jesse.vandam@wur.nl>, "public-rdf-shapes@w3.org" <public-rdf-shapes@w3.org>


On 07/20/2014 01:10 AM, Eric Prud'hommeaux wrote:
> * Evren Sirin <evren@clarkparsia.com> [2014-07-19 22:55-0400]

[...]

> One of the features of Resource Shapes is that, while it *can* be
> attached to a type, it frequently is not. Arthur Ryman spoke of this
> [[
> constraint language should be independent of any vocabulary or
> ontology
> ]] — <http://www.w3.org/mid/OFF14B15B5.802B33E2-ON85257D0A.004C62E1-85257D0A.005240FE@ca.ibm.com>
> and emphasized it in
> <http://www.w3.org/mid/OF026C08BD.7F379A54-ON85257D15.00456170-85257D15.0047EB06@ca.ibm.com>

Taken literally, this statement is rather extreme.  Constraint languages that 
are independent of vocabularies can only talk about reachability and 
connectedness.  I don't think that this is what is wanted here.

One can argue that particular vocabularies/ontologies should permit multiple 
sets of constraints.  I agree with this argument.  This does not make the 
constraints independent of the vocabulary or ontology, however.  In fact, 
every example of ShEx that I have seen is very tied to a particular vocabulary.



OWL and RDFS do not fail on this point at all.  One can use OWL and RDFS in a 
very flexible manner, where there is a base ontology and additional axioms.  A 
constraint system using OWL or RDFS can work in a similar fashion.

Even StarDog ICV can be used in this manner.  All you have to do is have an 
overall file that imports the base ontology and separately constraint-imports 
the constraints.  Different uses can have the same ontology and different 
constraints.  Some uses can even have just the constraints.  One could also 
have a trivial modification of StarDog ICV that had an extra explicit input - 
the constraints.

Argument 2 in 
http://lists.w3.org/Archives/Public/public-rdf-shapes/2014Jul/0076.html does 
not require anything that cannot be provided by StarDog ICV and many other 
constraint setups that are built on RDFS or OWL.


It is very hard to see how ShEx constraints can be associated with instances 
of RDFS types.  I view the ability to associate constraints with instances of 
types as the most important aspect of a constraint system, hence my questions 
about how this can be done in ShEx.



peter
Received on Sunday, 20 July 2014 09:05:32 UTC

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