Proposal for ISSUE-12 language-tagged literals

We have addressed one half of ISSUE-12, the half about string literals *without* language tags.

Here's a proposal for the other half, string literals *with* language tags and rdf:PlainLiteral. This is a very minimalist proposal.

- add classes rdf:LangString and rdf:Text so we can better specify string literals as rdfs:range of properties
- add the technical term “language-tagged string” as an alternative to the current “plain literal with language tag”
- ask OWL and RIF WGs to update rdf:PlainLiteral document to reflect the RDF WG decisions

(This completes my ACTION-62.)



A literal is either a typed literal or a language-tagged string.

A language-tagged string is an <Unicode string, language tag> pair.

"Plain literal with language tag" (from RDF 2004) is an alternative term for "language-tagged string". They are the same thing.

rdf:LangString is the class of all language-tagged strings. It can be used in rdfs:range statements.

rdf:Text is the class of all language-tagged strings and all Unicode strings. It can be used in rdfs:range statements.

The RDF Concepts document is updated with the definitions above. No other changes to RDF Concepts.

The RDF Semantics document is updated to make rdf:LangString and rdf:Text work. No other changes to RDF Semantics.

The RDF Schema document is updated to add rdf:LangString and rdf:Text. No other changes to RDF Schema.

The SPARQL WG is asked to *consider* whether DATATYPE("foo"@en) should return rdf:LangString instead of error.

The OWL and RIF WGs are asked to make changes to the rdf:PlainLiteral specification:

- Clarify that the purpose of the document is *solely* to provide
  compatibility between RDF and specifications whose literal
  design does not support language tags.

- The spec should be changed to *only* cover strings *with* language
  tags, because strings without language tags now always have a
  datatype (xsd:string) and therefore don't need to be covered in this

- Instead of defining its complete own datatype rdf:PlainLiteral,
  the spec should only extend the rdf:LangString class so that
  it can serve as a datatype.


Received on Wednesday, 13 July 2011 14:52:18 UTC