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add non-backtrackable and backtrackable global variables

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This commit is contained in:
Mark Thom
2019-03-13 00:16:57 -06:00
parent f0f8bfb569
commit 0eb2fb3d90
5 changed files with 19 additions and 14 deletions
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19
src/prolog/lib/builtins.pl
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@@ -6,13 +6,13 @@
(>)/2, (<)/2, (=\=)/2, (=:=)/2, (>=)/2, (=<)/2, (,)/2, (->)/2,
(;)/2, (=..)/2, (==)/2, (\==)/2, (@=<)/2, (@>=)/2, (@<)/2,
(@>)/2, (=@=)/2, (\=@=)/2, (:)/2, abolish/1, asserta/1,
assertz/1, bagof/3, bb_get/2, bb_put/2, call_cleanup/2,
call_with_inference_limit/3, catch/3, clause/2,
current_predicate/1, current_prolog_flag/2, expand_goal/2,
expand_term/2, findall/3, findall/4, once/1, repeat/0,
retract/1, set_prolog_flag/2, setof/3, setup_call_cleanup/3,
term_variables/2, throw/1, true/0, false/0, write/1,
write_canonical/1, writeq/1, write_term/2]).
assertz/1, bagof/3, bb_b_put/2, bb_get/2, bb_put/2,
call_cleanup/2, call_with_inference_limit/3, catch/3,
clause/2, current_predicate/1, current_prolog_flag/2,
expand_goal/2, expand_term/2, findall/3, findall/4, once/1,
repeat/0, retract/1, set_prolog_flag/2, setof/3,
setup_call_cleanup/3, term_variables/2, throw/1, true/0,
false/0, write/1, write_canonical/1, writeq/1, write_term/2]).
/* this is an implementation specific declarative operator used to implement call_with_inference_limit/3
and setup_call_cleanup/3. switches to the default trust_me and retry_me_else. Indexing choice
@@ -738,7 +738,10 @@ current_predicate(Pred) :-
; throw(error(type_error(predicate_indicator, Pred), current_predicate/1))
).
bb_put(Key, NewValue) :-
bb_put(Key, Value) :- atom(Key), !, '$store_global_var'(Key, Value).
bb_put(Key, _) :- throw(error(type_error(atom, Key), bb_put/2)).
bb_b_put(Key, NewValue) :-
( bb_get(Key, OldValue) ->
call_cleanup((store_global_var(Key, NewValue) ; false), store_global_var(Key, OldValue))
; call_cleanup((store_global_var(Key, NewValue) ; false), reset_global_var_at_key(Key))