- From: Irene Polikoff <irene@topquadrant.com>
- Date: Fri, 24 Feb 2017 22:17:09 -0500
- To: "Peter F. Patel-Schneider" <pfpschneider@gmail.com>
- Cc: "public-rdf-shapes@w3.org" <public-rdf-shapes@w3.org>
Peter, Do you have examples of the loss of expressive power in cases of sh:minCount, sh:maxCount, sh:uniqueLang, sh:lessThan, sh:lessThanOrEquals, or sh:qualifiedValueShape constraint component? Regards, Irene > On Feb 24, 2017, at 9:57 PM, Peter F. Patel-Schneider <pfpschneider@gmail.com> wrote: > > This is a formal objection to the decision of the RDF Data Shapes working > group to reclose ISSUE-139 by making node shapes ill-formed if they use any > of sh:minCount, sh:maxCount, sh:uniqueLang, sh:equals, sh:disjoint, > sh:lessThan, sh:lessThanOrEquals, or sh:qualifiedValueShape. > > Node shapes that use any of these properties have suitable obvious > definitions so there is no problem adding them back to SHACL. > > With the resolution node shapes and property shapes have different features. > This difference complicates the language, making it harder to explain to > users and harder to machine-generate. Because the language is more complex > implementations become more complex and testing becomes more complex. > > Removing these node shapes from the language causes a decided drop in > expressive power. For example, > > ex:s1 rdf:type sh:NodeShape ; > sh:targetClass ex:C1 ; > sh:disjoint ex:p1 . > > checks that SHACL instances of ex:C1 do not have themselves as a value for > ex:p1. This useful ability cannot be obtained through any other means. > > So the resolution to close ISSUE-139 removes useful expressive power from > SHACL without appreciably reducing implementation or testing costs or > reducing user confusion. All these features need to be added back to node > shapes. > > Peter F. Patel-Schneider > Nuance Communications >
Received on Saturday, 25 February 2017 03:17:44 UTC