SPARQL error

[felix]

Hi,

first up, thanks for this amazing project!

When trying to query my ontology, I got the following error message:
"Exception: What do I do with this CompValue? GroupGraphPatternSub_GroupGraphPatternSub_{'part': [TriplesBlock_{'triples': [[rdflib.term.Variable('op'), rdflib.term.URIRef('http://www.w3.org/1999/02/22-rdf-syntax-ns#type'), rdflib.term.URIRef('http://www.w3.org/2002/07/owl#FunctionalProperty')]], '_vars': {rdflib.term.Variable('op')}}], '_vars': {rdflib.term.Variable('op')}}"

Apparently this expression does not work:
BIND ( EXISTS { ?op a owl:FunctionalProperty } AS ?functional )
As a workaround, I found this uglier option to work:
OPTIONAL {
    ?op a owl:FunctionalProperty .
    BIND ( TRUE AS ?functional )
}
However, both options work in the SPARQL-Tab integrated in Protege.

I attached a minimal example that results in the error message above:
min_ex.py
My python version is 3.7.8 and package versions in use are:
* Owlready2 v0.24
* rdflib 5.0.0

Am I missing something here? Help would be greatly appreciated.

Best,
Felix

[Jiba]

Hi,

Owlready2 use RDFlib for SPARQL; I think the problem or limitation is actually in RDFlib.

Maybe you should report that to the RDFlib team.

Jiba