Cannot create named blank node as subject

[bjdmeest]

Issue type: :bug: Bug

Description

I wanna build something like https://rml.io/test-cases/#rmltc0001b-csv , but YARRRML below doesn't contain the termtype

Steps

mappings:
  loc:
    s:
      value: $(ID)_$(loc)
      type: blank

becomes (snippet)

map:s_000 rml:reference "firstname" ;
	rdf:type rr:SubjectMap .

Environment

Matey, and latest yarrrml-parser (1.5.2)