List1 = [1, 2, 3, 4, 5] &
List2 = [5, 6, 7, 8] &
ExpRes = [1, 2, 3, 4] &
compare (List1, List2, [], Result) &
append (Ls, NewElem, _NewLs);

append ([], NewElem, [NewElem]) :-
	!
;

append ([Head | Tail], NewElem, [Head | TempRes]) :-
	append (Tail, NewElem, TempRes)
;

compare ([], _List2, Acc, Acc) :-
	!
;

compare ([Head | Tail], List2, Acc, Res) :-
	not Head in List2 &
	! &
	append (Acc, Head , NewAcc) &
	compare (Tail, List2, NewAcc, Res)
;

compare ([_Head | Tail], List2, Acc, Res) :-
	compare (Tail, List2, Acc, Res)
;