Fig. 3

The RDF term type hierarchy as implemented in owlcpp. The RDF standard defines three types of terms implemented in owlcpp as the Node_iri, Node_literal, and Node_blank classes, which are accessed through the abstract Node interface. The abstract Node_literal class is further subtyped by concrete literal classes that represent the literal values as appropriate internal types, e.g., Node_bool for boolean types, Node_int for integers, etc. String-valued literals may also specify the language of their string values