// Namespaces have to be registered before loading RDF data
swipl.loadPrologCode("                                                     \n\
:- rdf_db:rdf_register_ns(nmr, 'http://www.nmrshiftdb.org/onto#').         \n\
:- rdf_db:rdf_register_ns(xsd, 'http://www.w3.org/2001/XMLSchema#').       ");

// Load RDF Data
swipl.loadRDFToProlog("nmrshiftdata.rdf.xml");

// Load the Prolog method we want to use for querying
swipl.loadPrologCode("                                                     \n\
hasSpectrumWithPeakWithShift( Molecule, Shift ) :-                         \n\
  rdf_db:rdf( Molecule, nmr:hasSpectrum, Spectrum ),                       \n\
  rdf_db:rdf( Spectrum, nmr:hasPeak, Peak ),                               \n\
  rdf_db:rdf( Peak,     nmr:hasShift, literal(type(xsd:decimal, Shift)) ). ");
  
// Query and output all molecules with shift = '42.2', limiting to 10 results
var molecules = swipl.queryProlog( [ "hasSpectrumWithPeakWithShift",
                                     "10", "Molecules", "'42.2'" ] );
// Output results to console
js.print(molecules);