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Re: On the inevitability of SPARQL/SPIN for SHAQL

From: Jose Emilio Labra Gayo <jelabra@gmail.com>
Date: Sun, 1 Mar 2015 10:39:46 +0100
Message-ID: <CAJadXXJkc2A2-BUBeJ+0zcHLQwkOTeg_Kp-LHA+vtvoZLWDZAw@mail.gmail.com>
To: Dimitris Kontokostas <jimkont@gmail.com>
Cc: Holger Knublauch <holger@topquadrant.com>, public-data-shapes-wg <public-data-shapes-wg@w3.org>
> >
> > It depends on what information has the post-schema-validation data
> structure and the context in which it is run.

If you are talking about the message errors, the post-schema-validation
data structure that I am talking about can easily be defined in terms of
the results of the axiomatic semantics that I proposed here:


In that axiomatic semantics, the validator returns a set of typings
(associations of nodes with shapes), a set of checked triples and a set of
remaining triples. From that information, error messages can be

If you are talking about the requirements on complex constraints, having an
extensibility mechanism allows to cover all those requirements. Those are
the "semantic actions" that are employed in ShEx and can have much more
uses than just handling complex constraints. For example they can be used
to transform RDF to other notations as described in [1].

The other alternative, based on XPath can handle most of the complex
constraints like arithmetic and string operations in a much more controlled
way. That proposal has not been implemented yet although it should not be

Best regards, Jose Labra

[1] Shape Expressions: An RDF validation and transformation language, Eric
Prud'hommeaux, Jose Emilio Labra Gayo, Harold Solbrig, 10th International
Conference on Semantic Systems, Sept. 2014, Leipzig, Germany,
PDF: http://labra.github.io/ShExcala/papers/semantics2014.pdf
Slides: http://www.slideshare.net/jelabra/semantics-2014

> Hi Jose,
> I think that we are in a point where we need concrete solutions or proof
> that your suggestion will be able to handle the requirements
> Best,
> Dimitris
> >
> > Best regards, Jose Labra

-- Jose Labra
Received on Sunday, 1 March 2015 09:40:34 UTC

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