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/* Part of SWI-Prolog
Author: Jan Wielemaker
E-mail: J.Wielemaker@vu.nl
WWW: http://www.swi-prolog.org
Copyright (c) 2019-2021, VU University Amsterdam
SWI-Prolog Solutions b.v.
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in
the documentation and/or other materials provided with the
distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
*/
:- module(increval,
[ incr_assert/1, % :Clause
incr_asserta/1, % :Clause
incr_assertz/1, % :Clause
incr_retractall/1, % :Head
incr_retract/1, % :Clause
is_incremental_subgoal/1, % :Goal
incr_directly_depends/2, % :Goal1, :Goal2
incr_trans_depends/2, % :Goal1, :Goal2
incr_invalid_subgoals/1, % -List
incr_is_invalid/1, % :Goal
incr_invalidate_call/1, % :Goal
incr_invalidate_calls/1, % :Goal
incr_table_update/0,
incr_propagate_calls/1 % :Answer
]).
:- use_module(library(tables)).
/** <module> Incremental dynamic predicate modification
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.
@compat XSB
*/
:- meta_predicate
incr_assert(:),
incr_asserta(:),
incr_assertz(:),
incr_retractall(:),
incr_retract(:),
is_incremental_subgoal(:),
incr_directly_depends(:,:),
incr_trans_depends(:, :),
incr_is_invalid(:),
incr_invalidate_call(:),
incr_invalidate_calls(:),
incr_propagate_calls(:).
incr_assert(T) :- assertz(T).
incr_asserta(T) :- asserta(T).
incr_assertz(T) :- assertz(T).
incr_retractall(T) :- retractall(T).
incr_retract(T) :- retract(T).
%! is_incremental_subgoal(?SubGoal) is nondet.
%
% This predicate non-deterministically unifies Subgoal with
% incrementally tabled subgoals that are currently table entries.
is_incremental_subgoal(SubGoal) :-
'$tbl_variant_table'(VTrie),
trie_gen(VTrie, SubGoal, ATrie),
( '$idg_edge'(ATrie, _Dir, _Value)
-> true
).
%! incr_directly_depends(:Goal1, :Goal2) is nondet.
%
% True if Goal1 depends on Goal2 in the IDG.
%
% @compat: In XSB, at least one of Goal 1 or Goal 2 must be bound.
% This implementation may be used with both arguments unbound.
incr_directly_depends(Goal1, Goal2) :-
'$tbl_variant_table'(VTrie),
( nonvar(Goal2)
-> trie_gen(VTrie, Goal2, ATrie2),
'$idg_edge'(ATrie2, affected, ATrie1),
'$tbl_table_status'(ATrie1, _Status, Goal1, _Return)
; trie_gen(VTrie, Goal1, ATrie1),
'$idg_edge'(ATrie1, dependent, ATrie2),
'$tbl_table_status'(ATrie2, _Status, Goal2, _Return)
).
%! incr_trans_depends(:Goal1, Goal2) is nondet.
%
% True for each pair in the transitive closure of
% incr_directly_depends(G1, G2).
incr_trans_depends(Goal1, Goal2) :-
'$tbl_variant_table'(VTrie),
( nonvar(Goal1)
-> trie_gen(VTrie, Goal1, ATrie1),
incr_trans_depends(ATrie1, dependent, ATrie2, []),
'$tbl_table_status'(ATrie2, _Status, Goal2, _Return)
; trie_gen(VTrie, Goal2, ATrie2),
incr_trans_depends(ATrie2, affected, ATrie1, []),
'$tbl_table_status'(ATrie1, _Status, Goal1, _Return)
).
incr_trans_depends(ATrie1, Dir, ATrie, Done) :-
'$idg_edge'(ATrie1, Dir, ATrie2),
\+ memberchk(ATrie2, Done),
( ATrie = ATrie2
; incr_trans_depends(ATrie2, Dir, ATrie, [ATrie2|Done])
).
%! incr_invalid_subgoals(-List) is det.
%
% List is a sorted list (set) of the incremental subgoals that are
% currently invalid.
incr_invalid_subgoals(List) :-
findall(Invalid, invalid_subgoal(Invalid, _), List0),
sort(List0, List).
invalid_subgoal(Goal, ATrie) :-
'$tbl_variant_table'(VTrie),
trie_gen(VTrie, Goal, ATrie),
( '$idg_edge'(ATrie, _Dir, _Value)
-> true
),
'$idg_falsecount'(ATrie, Count),
Count > 0,
\+ '$tbl_table_status'(ATrie, dynamic, _Goal, _Return).
%! incr_is_invalid(:Subgoal) is semidet.
%
% True when Subgoal's table is marked as invalid.
incr_is_invalid(Subgoal) :-
get_calls(Subgoal, Table, _Return),
'$idg_falsecount'(Table, Count),
Count > 0.
%! incr_invalidate_calls(:Goal) is det.
%
% Invalidate all tables for subgoals of Goal as well as tables that
% are affected by these.
incr_invalidate_calls(Goal) :-
'$tbl_variant_table'(VTable),
!,
forall(trie_gen(VTable, Goal, ATrie),
'$idg_changed'(ATrie)).
incr_invalidate_calls(_).
%! 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_invalidate_call(Goal) :-
incr_invalidate_calls(Goal).
%! incr_table_update
%
% Updated all invalid tables
incr_table_update :-
repeat,
( invalid_subgoal(Goal, ATrie)
-> '$tabling':reeval(ATrie, Goal, _Return),
fail
; !
).
%! incr_propagate_calls(:Answer) is det.
%
% Activate the monotonic answer propagation similarly to when a new
% fact is asserted for a monotonic dynamic predicate. The Answer term
% must match a monotonic dynamic predicate.
incr_propagate_calls(Answer) :-
setup_call_cleanup(
'$tbl_propagate_start'(Old),
'$tabling':incr_propagate_assert(Answer),
'$tbl_propagate_end'(Old)).
|
