How does grep command compare a hash element with an array of hash references?

[Vaishnavi Saba]

Hi,

My query: In the code shown below, How does *grep* compare a scalar( *
$seen{$_}* ) with an array of hash references ( *...@_* ).

=====

@common = inter( \%foo, \%bar, \%joe );
sub inter {
    my %seen;
    for my $href (@_) {
        while (my $k = each %$href ) {
            $seen{$k}++;
        }
    }

return grep { $seen{$_} == @_ } keys %seen;

}

========

When I try printing the @_, I get the output as "HASH(0x40030354)
HASH(0x400303d8) HASH(0x40037e98)".

Cheers,
Shalu