package AAA;
use parent('Exporter');
our @EXPORT=('$bbb');
our $bbb=BBB->new();

package BBB;
use AAA;
use feature 'say';
sub new{
    my $class=shift;
    my $self=bless {},$class;
    return $self;
}
sub hello{
    my $self=shift;
    say 'hello';
}
sub hello2{
    my $self=shift;
    #$b->hello(); #what is $b?
    $bbb->hello();
}

package main;
use AAA;
$bbb->hello2();