tabling.pl -- Tabled execution (SLG WAM)

This library handled tabled execution of predicates using the characteristics if the SLG WAM. The required suspension is realised using delimited continuations implemented by reset/3 and shift/1. The table space and work lists are part of the SWI-Prolog core.

author

- Benoit Desouter

 table(+PredicateIndicators)

Prepare the given PredicateIndicators for tabling. Can only be used as a directive. The example below prepares the predicate edge/2 and the non-terminal statement//1 for tabled execution.

:- table edge/2, statement//1.

In addition to using predicate indicators, a predicate can be declared for mode directed tabling using a term where each argument declares the intended mode. For example:

:- table connection(_,_,min).

Mode directed tabling is discussed in the general introduction section about tabling.

 start_tabling(+Variant, +Implementation)

Execute Implementation using tabling. This predicate should not be called directly. The table/1 directive causes a predicate to be translated into a renamed implementation and a wrapper that involves this predicate.

Compatibility

- This interface may change or disappear without notice from future versions.

 abolish_all_tables

Remove all tables. This is normally used to free up the space or recompute the result after predicates on which the result for some tabled predicates depend.

Errors

- permission_error(abolish, table, all) if tabling is in progress.

 abolish_table_subgoals(:Subgoal) is det

Abolish all tables that unify with SubGoal.

 current_table(:Variant, -Trie) is nondet

True when Trie is the answer table for Variant.

 prolog:rename_predicate(:Head0, :Head) is semidet[multifile]

Hook into term_expansion for post processing renaming of the generated predicate.

 sandbox:safe_directive(+Directive) is semidet[multifile]

Allow tabling directives that affect locally defined predicates.