:- use_module(library(lists), [member/2]).

ppp :-
	findall(pp(Head,Body),pp(Head,Body),Program1),
	reverse_program(Program1,[],Program2),
	Query = run(_),
	findall(Query,exec(Query,Program1),Answers1),
	findall(Query,exec(Query,Program2),Answers2),
	is_a_copy(Answers1,Answers2).

exec((Goal1,Goal2),Program) :- !,
	exec(Goal1,Program),
	exec(Goal2,Program).
exec(true,_) :- !.
exec(Head,Program) :-
	member(Clause,Program),
	copy_term(Clause,pp(Head,Body)),
	exec(Body,Program).

reverse_program([],L,L).
reverse_program([pp(H,B)|R],In,Out) :-
	reverse_body(B,true,NewB),
	reverse_program(R,[pp(H,NewB)|In],Out).

reverse_body((A,B),In,Out) :- !, reverse_body(B,(A,In),Out).
reverse_body(A,In,(A,In)).

is_a_copy(A,B) :-
	numbervars(A,1,N),
	numbervars(B,1,N),
	A = B.