This module emulates the XSB module increval. This module serves two goals: (1) provide alternatives for the dynamic clause manipulation predicates that propagate into the incremental tables and (2) query the dynamically maintained Incremental Depency Graph (IDG).

The change propagation for incremental dynamic predicates. SWI-Prolog relies in prolog_listen/2 to forward any change to dynamic predicates to the table IDG and incr_assert/1 and friends thus simply call the corresponding database update.

Compatibility

- XSB

 is_incremental_subgoal(?SubGoal) is nondet

This predicate non-deterministically unifies Subgoal with incrementally tabled subgoals that are currently table entries.

 incr_directly_depends(:Goal1, :Goal2) is nondet

True if Goal1 depends on Goal2 in the IDG.

Compatibility

- : In XSB, at least one of Goal 1 or Goal 2 must be bound. This implementation may be used with both arguments unbound.

 incr_trans_depends(:Goal1, Goal2) is nondet

True for each pair in the transitive closure of incr_directly_depends(G1, G2).

 incr_invalid_subgoals(-List) is det

List is a sorted list (set) of the incremental subgoals that are currently invalid.

 incr_is_invalid(:Subgoal) is semidet

True when Subgoal's table is marked as invalid.

 incr_invalidate_calls(:Goal) is det

Invalidate all tables for subgoals of Goal as well as tables that are affected by these.

 incr_invalidate_call(:Goal) is det

This is the XSB name, but the manual says incr_invalidate_calls/1 and the comment with the code suggests this is misnamed.

deprecated

- Use incr_invalidate_calls/1.

 incr_table_update

Updated all invalid tables

 incr_propagate_calls(:Answer) is det

Activate the monotonic answer propagation similarly to when a new fact is asserted for a monotonic dynamic predicate. The Answer term must match a monotonic dynamic predicate.

Undocumented predicates

The following predicates are exported, but not or incorrectly documented.

 incr_retractall(Arg1)

 incr_retract(Arg1)

 incr_assert(Arg1)

 incr_asserta(Arg1)

 incr_assertz(Arg1)