Allow blank node labels as annotation values

[joeltg]

PREFIX schema: <http://schema.org/>
PREFIX prov: <http://www.w3.org/ns/prov#>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
PREFIX ex: <http://example.com/>

_:foo {
  schema:name xsd:string // ex:reference _:bar ;
}

_:bar {
  a [ prov:Entity ] ;
  prov:generatedAtTime xsd:dateTime ;
}

Some kinds of annotations might want to reference blank node labels from the schema! Is there any reason not to allow this?

[ericprud]

i actually mocked up a full ShEx-with-Turtle at some point but figured it would be complex enough that it would hamper implementation and adoption 'cause

1. the grammar was about 20% larger
2. parsers would become triple stores.

That said, I'm not convinced that I figured that right, or that the audience hasn't become more ambitious.