Incorrect Data Type for `sh:namespace` in SHACL Declaration

[Zakaria29041996]

Description:

In the SHACL (Shapes Constraint Language) RDF ontology, the sh:declare statement currently specifies the sh:namespace as a plain string:

sh:declare [
    sh:prefix "sh" ;
    sh:namespace "http://www.w3.org/ns/shacl#" ;
] ;

This can lead to issues with certain reasoners, especially when the SHACL ontology is indirectly imported. Some reasoners expect the sh:namespace to be explicitly typed as xsd:anyURI for correct interpretation.

Proposed Change:

To ensure compatibility with reasoners and avoid errors, the sh:namespace should be explicitly typed as xsd:anyURI:

sh:declare [
    sh:prefix "sh" ;
    sh:namespace "http://www.w3.org/ns/shacl#"^^xsd:anyURI ;
] ;

This change will help resolve the issues encountered with reasoners that rely on type checking for URI values.

[VladimirAlexiev]

Right!
This conflicts with the definition later on:

sh:namespace
	rdfs:range xsd:anyURI ;

Note: the analogous property vann:preferredNamespaceUri doesn't define a range, but sh:namespace does.

[VladimirAlexiev]

Complex shapes in the electrical industry (eg https://raw.githubusercontent.com/Sveino/Inst4CIM-KG/refs/heads/develop/source/CGMES/v3.0/SHACL/ttl/61970-301_Equipment-AP-Con-Complex-SHACL_v3-0-0.ttl) import the `sh: ontology.
If you validate them with https://www.itb.ec.europa.eu/shacl/shacl/upload as reported in ISAITB/shacl-validator#14, you get one error:

The values of sh:namespace are literals of datatype xsd:anyURI.

As documented in https://github.com/Sveino/Inst4CIM-KG/tree/develop/shacl-improved#check-for-syntax-errors-using-shacl-shacl

Paradoxically, the 1 error is the result of importing the sh: ontology, which has sh:declare/sh:namespace as strings rather than xsd:anyURI.

[HolgerKnublauch]

This issue was already fixed in 2021, as the latest version of sh.ttl is here:

https://github.com/w3c/data-shapes/blob/gh-pages/shacl/shacl.ttl

Unfortunately that version has not been published yet to

https://www.w3.org/ns/shacl#

which displays a link to

https://www.w3.org/ns/shacl.ttl

If it's not too much work, we could update those files soon, if just to close this ticket and relieve some of the follow-up problems. But I don't know what the process would be to publish these files.

[HolgerKnublauch]

Closing as duplicate as it will be fixed by #244