%hash
    $id
        $position
            key1   = (scalar)
            type_a = { subkey1 => (scalar)
                       subkey2 => (scalar)
                       subkey3 => (scalar)
                     }
            list_1 = [ ]

##</code><code>##

my $value = $hash{$id}{$position}{type_a}{subkey2};

##</code><code>##

my $value = get_typea_sk2( $id, $position );

sub get_typea_sk2
{
    return $hash{$id}{$position}{type_a}{subkey2};
}

##</code><code>##

%hash
    $id => $objref

##</code><code>##

%hash
    $id
        $position => $objref
        $position => $objref

##</code><code>##

my $obj = get_object( $id, $position );
# use methods on $obj to get data

sub get_object
{
    return $hash{ $_[0] }{ $_[1] };
}