SOQL does not support ordering by identifier

[ledsoft]

I am not able to order query results in SOQL by the identifier of the root object. For example, the following query cannot be parsed (query parser throws an exception):

SELECT p FROM Person p ORDER BY p.uri

The expected SPARQL looks as follows (assuming Person is foaf:Person):

SELECT ?x WHERE { ?x a foaf:Person . } ORDER BY ?x

Even attempting a workaround using

SELECT p FROM Person p ORDER BY p

does not work