- rdf_insert_literal_map(+Map, +Key, +Value, -KeyCount) is det
- As rdf_insert_literal_map/3. In addition, if Key is a new key in
Map, unify KeyCount with the number of keys in Map. This serves
two purposes. Derived maps, such as the stem and metaphone maps
need to know about new keys and it avoids additional foreign
calls for doing the progress in
rdf_litindex.pl.