RDF.XSD.Datatype.Primitive.def_applicable_facet

You're seeing just the macro def_applicable_facet, go back to RDF.XSD.Datatype.Primitive module for more information.
Link to this macro

def_applicable_facet(facet)

View Source (macro)

Specifies the applicability of the given XSD facet on a primitive datatype.

For a facet with the name example_facet this requires a function

def example_facet_conform?(example_facet_value, literal_value, lexical) do

end

to be defined on the primitive datatype.