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Re: on focus nodes

From: Dimitris Kontokostas <kontokostas@informatik.uni-leipzig.de>
Date: Tue, 11 Oct 2016 18:06:29 +0300
Message-ID: <CA+u4+a0D2MxYTR5Gs2f9n1cKS4r3A8Gk-XmvMm1AhdMKADmJDg@mail.gmail.com>
To: "Peter F. Patel-Schneider" <pfpschneider@gmail.com>
Cc: "public-rdf-shapes@w3.org" <public-rdf-shapes@w3.org>
Dear Peter, thank you for your comments
note that this is an unofficial response that is not necessarily endorsed
by the WG

For your information, we updated the definition and use of the term focus
Can you check if this looks good to you now?


On Tue, Oct 4, 2016 at 5:26 PM, Peter F. Patel-Schneider <
pfpschneider@gmail.com> wrote:

> The notion of focus nodes is poorly defined in the SHACL document.
> The first mention of focus nodes is:
> "Focus Node
> A node in the data graph that is validated against a shape is called a
> focus
> node."
> This indicates that any node that is validated against a shape is a focus
> node but doesn't say how they are determined.
> Right after, there is
> "Target
> A target relates a shape with its focus nodes."
> This indicates that the only focus nodes are those that come via targets.
> Later there is
> "Shapes define constraints that a set of focus nodes can be validated
> against. The set of focus nodes for a shape may be defined explicitly in a
> shape using targets and filters. The focus nodes may also be determined as
> part of the validation of constraints that include references to shapes
> using properties such as sh:shape and sh:or."
> This states that here are two ways of determining the focus nodes of a
> shape.  Either all the focus nodes come from targets and filters or all
> the focus nodes are determined during validation.
> The diagram just after then shows targets selecting focus nodes, counter to
> having both targets and filters selecting focus nodes.
> This is another example of loose terminology in the SHACL document.  The
> entire document needs to be closely examined to ensure that the term focus
> node is defined clearly and coherently.  This needs to be accompanied by a
> repeated examination of the document for loose terminology that only
> terminates when no examples of loose terminology are present.
> Peter F. Patel-Schneider
> Nuance Communications

Dimitris Kontokostas
Department of Computer Science, University of Leipzig & DBpedia Association
Projects: http://dbpedia.org, http://rdfunit.aksw.org,
Homepage: http://aksw.org/DimitrisKontokostas
Research Group: AKSW/KILT http://aksw.org/Groups/KILT
Received on Tuesday, 11 October 2016 15:07:26 UTC

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