use base 'Sub::Attributes';

sub reverse_me : Arrayref(NOVOID) { # calling in void context is now fatal
    return reverse @_;
}

my @list = reverse_me(1,2,3); # (3,2,1)
my $list = reverse_me(1,2,3); # [3,2,1]

sub do_stuff : Iterator { # calling in void context is legal, but a no-op
    return @_;
}

my @list = do_stuff(1,2,3); # simply returns the list
my $list = do_stuff(1,2,3); # iterator object

print $iterator->next; # prints 1
print $iterator->next; # prints 2
print $iterator->next; # prints 3
print $iterator->prev; # prints 3
print $iterator->prev; # prints 2
print $iterator->prev; # prints 1