%main.pl

:- [family].

print_query_true(Q) :-
    forall(Q, writeln(true:Q)).

print_query_false(Q) :-
    forall(\+ Q, writeln(false:Q)).

run_opt(1) :- 
    write('>   Enter a query followed by a period.'), nl,
    read(Query),
    print_query_true(Query),
    print_query_false(Query).

run_opt(2) :- write('Goodbye'), nl, halt. 

run_opt(_) :- write('Invalid option'), nl, halt.  

main :- 
    nl,
    write('>   Enter a selection followed by a period.'), nl,
    write('>   1. Run a query'), nl,
    write('>   2. Exit'), nl, nl,
    read(Choice),
    run_opt(Choice), main.