Support for rdf:HTML as a type of literal

[ralphtq]

Could we extend object RDFNode as follows:

val RDFhtmlStringDatatypeIRI = IRI(rdfSyntax + "HTML")

in:

object RDFNode {
val xsd = "http://www.w3.org/2001/XMLSchema#"
val rdfSyntax = "http://www.w3.org/1999/02/22-rdf-syntax-ns#"
val StringDatatypeIRI = IRI(xsd + "string")
val RDFhtmlStringDatatypeIRI = IRI(rdfSyntax + "HTML")
val LangStringDatatypeIRI = IRI(rdfSyntax + "langString")
val BooleanDatatypeIRI = IRI(xsd + "boolean")
val IntegerDatatypeIRI = IRI(xsd + "integer")
val DoubleDatatypeIRI = IRI(xsd + "double")
val DecimalDatatypeIRI = IRI(xsd + "decimal")
val rdftype = IRI(rdfSyntax + "type")
val rdfnil = IRI(rdfSyntax + "nil")
val rdffirst = IRI(rdfSyntax + "first")
val rdfrest = IRI(rdfSyntax + "rest")
...
...

Ralph

[ralphtq]

I've forked srdf and made a start on supporting rdf:HTML.

This is the branch I have in my fork: https://github.com/ralphtq/srdf/tree/rh-master-rdfhtml

Need now to understand how to do the PR process and make snapshots.

Ralph

[labra]

Thanks for the suggestion and the code...in principle it seems it works.

I also added support for rdf:XMLLiteral as well and it has been published as version 0.1.113

I keep the isse open by now until you confirm it is working as expected and we can close the issue.

[ralphtq]

Further work was needed to overcome this error:

New branch is https://github.com/ralphtq/srdf/tree/rh-master-rdfhtml-inc2

This is the change:

node match {
  case b: BNode =>
    m.createResource(new AnonId(b.id.toString))
  case i: IRI =>
    m.createResource(resolve(i, base))
  case StringLiteral(str) =>
    m.createLiteral(str, false)
  case RDFHTMLLiteral(str) =>    // RH20220820
    m.createLiteral(str, false)  // RH20220820
    ....

Ralph

[ralphtq]

Changes also needed in shacl-s.

See weso/shacl-s#203

[ralphtq]

On recent testing the support for rdf:HTML is failing in the JenaMapper.

I have this test:

it("Should compare one triple with a rdf:HTML literal") {
  val ts = Set(RDFTriple(BNode("b" + 0), IRI("http://example.org#p"), RDFHTMLLiteral("<div>Test HTML markup</div>")))
  val s =
    """|@prefix : <http://example.org#> .
       |_:a :p "<div>Test HTML markup</div>"^^rdf:HTML .""".stripMargin
  println(s"ts: $ts")
  val empty = ModelFactory.createDefaultModel
  val model1 = RDFTriples2Model(ts, empty, None)
  val model2 = str2model(s)
  shouldBeIsomorphic(model1, model2)
}

With these results:

ts: Set(_:b0 http://example.org#p "

Test HTML markup

"^^rdf:HTML)
model1: <ModelCom {b0 @http://example.org#p "

Test HTML markup

"} | [b0, http://example.org#p, "

Test HTML markup

"]>
[info] - Should compare one triple with a rdf:HTML literal *** FAILED ***
[info] org.apache.jena.riot.RiotException: [line: 2, col: 39] Undefined prefix: rdf
[info] at org.apache.jena.riot.system.ErrorHandlerFactory$ErrorHandlerStd.fatal(ErrorHandlerFactory.java:163)
[info] at org.apache.jena.riot.system.ParserProfileStd.expandPrefixedName(ParserProfileStd.java:322)
[info] at org.apache.jena.riot.system.ParserProfileStd.create(ParserProfileStd.java:282)
[info] at org.apache.jena.riot.lang.LangTurtleBase.tokenAsNode(LangTurtleBase.java:577)
[info] at org.apache.jena.riot.lang.LangTurtleBase.node(LangTurtleBase.java:410)
[info] at org.apache.jena.riot.lang.LangTurtleBase.triplesNode(LangTurtleBase.java:445)
[info] at org.apache.jena.riot.lang.LangTurtleBase.objectList(LangTurtleBase.java:419)
[info] at org.apache.jena.riot.lang.LangTurtleBase.predicateObjectItem(LangTurtleBase.java:352)
[info] at org.apache.jena.riot.lang.LangTurtleBase.predicateObjectList(LangTurtleBase.java:333)
[info] at org.apache.jena.riot.lang.LangTurtleBase.triples(LangTurtleBase.java:314)
[info] ...

RDFHTMLLiteral is working but the transfer to the Jena model is failing.

I have traced the error to this function in "ParserProfileStd.java", starting at line 317:

private String expandPrefixedName(String prefix, String localPart, Token token) {
    String expansion = prefixMap.expand(prefix, localPart);
    if ( expansion == null ) {
        if ( ARQ.isTrue(ARQ.fixupUndefinedPrefixes) )
            return RiotLib.fixupPrefixIRI(prefix, localPart);
        errorHandler.fatal("Undefined prefix: " + prefix, token.getLine(), token.getColumn());
    }
    return expansion;
}