% common code between the two ppp solutions

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

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.