( 1, 2, undef, undef, 5 ) ( 1, 2, 3, 4, undef ) #### ( 1, 2, undef, undef, undef ) ( 1, 2, 3, 4, undef ) #### (parent, sally, tom) (parent, bill, tom) (parent, tom, sue) (parent, alice, sue) (parent, sarah, tim) (male, bill) (male, tom) (male, tim) #### ( , (parent, $person, $anyone), (male, $person) ) #### #!/usr/bin/perl use strict; use warnings; use AI::Prolog; my $prolog = AI::Prolog->new(<query('father(Whom)'); while (my $results = $prolog->results) { print "@$results\n"; } __END__ father bill father tom