300 lines
7.8 KiB
Prolog
300 lines
7.8 KiB
Prolog
/*************************************************************************
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* *
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* YAP Prolog *
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* *
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* Yap Prolog was developed at NCCUP - Universidade do Porto *
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* *
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* Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997 *
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* *
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**************************************************************************
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* *
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* File: control.yap *
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* Last rev: 20/08/09 *
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* mods: *
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* comments: control predicates available in yap *
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* *
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*************************************************************************/
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once(G) :- '$execute'(G), !.
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forall(Cond, Action) :- \+((Cond, \+(Action))).
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ignore(Goal) :- (Goal->true;true).
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if(X,Y,Z) :-
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yap_hacks:env_choice_point(CP0),
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(
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CP is '$last_choice_pt',
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'$call'(X,CP,if(X,Y,Z),M),
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'$execute'(X),
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'$clean_ifcp'(CP),
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'$call'(Y,CP,if(X,Y,Z),M)
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;
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'$call'(Z,CP,if(X,Y,Z),M)
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).
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call(X,A) :- '$execute'(X,A).
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call(X,A1,A2) :- '$execute'(X,A1,A2).
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call(X,A1,A2,A3) :- '$execute'(X,A1,A2,A3).
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call(X,A1,A2,A3,A4) :- '$execute'(X,A1,A2,A3,A4).
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call(X,A1,A2,A3,A4,A5) :- '$execute'(X,A1,A2,A3,A4,A5).
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call(X,A1,A2,A3,A4,A5,A6) :- '$execute'(X,A1,A2,A3,A4,A5,A6).
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call(X,A1,A2,A3,A4,A5,A6,A7) :- '$execute'(X,A1,A2,A3,A4,A5,A6,A7).
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call(X,A1,A2,A3,A4,A5,A6,A7,A8) :- '$execute'(X,A1,A2,A3,A4,A5,A6,A7,A8).
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call(X,A1,A2,A3,A4,A5,A6,A7,A8,A9) :- '$execute'(X,A1,A2,A3,A4,A5,A6,A7,A8,A9).
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call(X,A1,A2,A3,A4,A5,A6,A7,A8,A9,A10) :- '$execute'(X,A1,A2,A3,A4,A5,A6,A7,A8,A9,A10).
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call(X,A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11) :- '$execute'(X,A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11).
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call_cleanup(Goal, Cleanup) :-
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setup_call_catcher_cleanup(true, Goal, _Catcher, Cleanup).
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call_cleanup(Goal, Catcher, Cleanup) :-
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setup_call_catcher_cleanup(true, Goal, Catcher, Cleanup).
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setup_call_cleanup(Setup, Goal, Cleanup) :-
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setup_call_catcher_cleanup(Setup, Goal, Catcher, Cleanup).
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setup_call_catcher_cleanup(Setup, Goal, Catcher, Cleanup) :-
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yap_hacks:disable_interrupts,
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'$do_setup'(Setup),
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catch('$safe_call_cleanup'(Goal,Cleanup,Catcher,Exception),
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Exception,
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'$cleanup_exception'(Exception,Catcher,Cleanup)).
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% this is simple, do nothing
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'$do_setup'(A:true) :- atom(A), !.
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% this is tricky: please don't forget that interrupts are disabled at this point
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% and that they will only be enabled after setting up Cleanup
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'$do_setup'(Setup) :-
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(
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'$execute'(Setup),
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% we don't need to care about enabling interrupts
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!
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;
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% reenable interrupts if Setup failed
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yap_hacks:enable_interrupts,
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fail
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).
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'$cleanup_exception'(Exception, exception(Exception), Cleanup) :- !,
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% whatever happens, let exception go through
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catch('$clean_call'(_,Cleanup),_,true),
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throw(Exception).
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'$cleanup_exception'(Exception, _, _) :-
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throw(Exception).
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'$safe_call_cleanup'(Goal, Cleanup, Catcher, Exception) :-
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yap_hacks:current_choice_point(MyCP1),
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'$freeze_goal'(Catcher, '$clean_call'(Exception, Cleanup)),
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yap_hacks:trail_suspension_marker(Catcher),
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(
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yap_hacks:enable_interrupts,
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yap_hacks:current_choice_point(CP0),
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'$execute'(Goal),
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% ensure environment for delayed variables in Goal
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'$true',
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yap_hacks:current_choice_point(CPF),
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(
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CP0 =:= CPF
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->
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Catcher = exit,
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!
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;
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true
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)
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;
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Catcher = fail,
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fail
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).
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'$holds_true'.
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% The first argument is used by JumpEnv to verify if a throw
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% is going to be handled by the cleanup catcher. If it is so,
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% clean_call will not be called from JumpToEnv.
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'$clean_call'(_,Cleanup) :-
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'$execute'(Cleanup), !.
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'$clean_call'(_,_).
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%%% The unknown predicate,
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% informs about what the user wants to be done when
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% there are no clauses for a certain predicate */
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unknown(V0,V) :-
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'$current_module'(M),
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'$unknown'(V0,V,M).
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% query mode
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'$unknown'(V0,V,_) :- var(V), !,
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'$ask_unknown_flag'(V),
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V = V0.
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% handle modules.
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'$unknown'(V0,Mod:Handler,_) :-
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'$unknown'(V0,Handler,Mod).
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% check if we have one we like.
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'$unknown'(_,New,Mod) :-
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'$valid_unknown_handler'(New,Mod), fail.
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% clean up previous unknown predicate handlers
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'$unknown'(Old,New,Mod) :-
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recorded('$unknown','$unknown'(_,MyOld),Ref), !,
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erase(Ref),
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'$cleanup_unknown_handler'(MyOld,Old),
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'$new_unknown'(New, Mod).
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% store the new one.
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'$unknown'(fail,New,Mod) :-
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'$new_unknown'(New, Mod).
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'$valid_unknown_handler'(V,_) :-
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var(V), !,
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'$do_error'(instantiation_error,yap_flag(unknown,V)).
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'$valid_unknown_handler'(fail,_) :- !.
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'$valid_unknown_handler'(error,_) :- !.
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'$valid_unknown_handler'(warning,_) :- !.
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'$valid_unknown_handler'(S,M) :-
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functor(S,_,1),
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arg(1,S,A),
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var(A),
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\+ '$undefined'(S,M),
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!.
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'$valid_unknown_handler'(S,_) :-
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'$do_error'(domain_error(flag_value,unknown+S),yap_flag(unknown,S)).
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'$ask_unknown_flag'(Old) :-
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recorded('$unknown','$unknown'(_,MyOld),_), !,
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'$cleanup_unknown_handler'(MyOld,Old).
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'$ask_unknown_flag'(fail).
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'$cleanup_unknown_handler'('$unknown_error'(_),error) :- !.
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'$cleanup_unknown_handler'('$unknown_warning'(_),warning) :- !.
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'$cleanup_unknown_handler'(Handler, Handler).
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'$new_unknown'(fail,_) :- !.
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'$new_unknown'(error,_) :- !,
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recorda('$unknown','$unknown'(P,'$unknown_error'(P)),_).
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'$new_unknown'(warning,_) :- !,
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recorda('$unknown','$unknown'(P,'$unknown_warning'(P)),_).
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'$new_unknown'(X,M) :-
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arg(1,X,A),
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recorda('$unknown','$unknown'(A,M:X),_).
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'$unknown_error'(Mod:Goal) :-
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functor(Goal,Name,Arity),
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'$program_continuation'(PMod,PName,PAr),
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'$do_error'(existence_error(procedure,Name/Arity),context(Mod:Goal,PMod:PName/PAr)).
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'$unknown_warning'(Mod:Goal) :-
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functor(Goal,Name,Arity),
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'$program_continuation'(PMod,PName,PAr),
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print_message(error,error(existence_error(procedure,Name/Arity), context(Mod:Goal,PMod:PName/PAr))),
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fail.
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%%% Some "dirty" predicates
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% Only efective if yap compiled with -DDEBUG
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% this predicate shows the code produced by the compiler
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'$show_code' :- '$debug'(0'f). %' just make emacs happy
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grow_heap(X) :- '$grow_heap'(X).
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grow_stack(X) :- '$grow_stack'(X).
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%
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% gc() expects to be called from "call". Make sure it has an
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% environment to return to.
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%
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%garbage_collect :- save(dump), '$gc', save(dump2).
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garbage_collect :-
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'$gc'.
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gc :-
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yap_flag(gc,on).
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nogc :-
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yap_flag(gc,off).
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garbage_collect_atoms :-
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'$atom_gc'.
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'$force_environment_for_gc'.
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'$good_list_of_character_codes'(V) :- var(V), !.
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'$good_list_of_character_codes'([]).
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'$good_list_of_character_codes'([X|L]) :-
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'$good_character_code'(X),
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'$good_list_of_character_codes'(L).
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'$good_character_code'(X) :- var(X), !.
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'$good_character_code'(X) :- integer(X), X > -2, X < 256.
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(initialization) :-
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'$initialisation_goals'.
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prolog_initialization(G) :- var(G), !,
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'$do_error'(instantiation_error,initialization(G)).
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prolog_initialization(T) :- callable(T), !,
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'$assert_init'(T).
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prolog_initialization(T) :-
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'$do_error'(type_error(callable,T),initialization(T)).
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'$assert_init'(T) :- recordz('$startup_goal',T,_), fail.
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'$assert_init'(_).
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version :- '$version'.
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version(V) :- var(V), !,
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'$do_error'(instantiation_error,version(V)).
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version(T) :- atom(T), !, '$assert_version'(T).
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version(T) :-
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'$do_error'(type_error(atom,T),version(T)).
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'$assert_version'(T) :- recordz('$version',T,_), fail.
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'$assert_version'(_).
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'$set_toplevel_hook'(_) :-
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recorded('$toplevel_hooks',_,R),
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erase(R),
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fail.
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'$set_toplevel_hook'(H) :-
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recorda('$toplevel_hooks',H,_),
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fail.
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'$set_toplevel_hook'(_).
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halt :-
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print_message(informational, halt),
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'$halt'(0).
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halt(X) :-
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'$halt'(X).
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prolog_current_frame(Env) :-
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Env is '$env'.
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'$run_atom_goal'(GA) :-
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'$current_module'(Module),
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atom_codes(GA,Gs0),
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'$add_dot_to_atom_goal'(Gs0,Gs),
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charsio:open_mem_read_stream(Gs, Stream),
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( '$system_catch'(read(Stream, G),Module,_,fail) ->
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close(Stream)
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;
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close(Stream),
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fail
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),
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'$system_catch'('$query'(once(G), []),Module,Error,user:'$Error'(Error)).
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'$add_dot_to_atom_goal'([],[0'.]) :- !. %'
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'$add_dot_to_atom_goal'([0'.],[0'.]) :- !.
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'$add_dot_to_atom_goal'([C|Gs0],[C|Gs]) :-
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'$add_dot_to_atom_goal'(Gs0,Gs).
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