2.18.1 Future directions

• The current indexing system is largely prepared for secondary indexes. This implies that if there are many clauses that match a given key, the system could (JIT) create a secondary index. This secondary index could exploit another argument or, if the key denotes a functor, an argument inside the compound term.

• The `special cases' can be extended. This is notably attractive for static predicates with a relatively small number of clauses where a hash lookup is too costly.