my( %dbh_of, %dir_of, ...);

my %props = (
    dbh => \%dbh_of,
    dir => \%dir_of,
    ...
);

sub get {
    my($self,$attr) = @_;
    my $return_val;
  
    # if valid attribute, return the object's value
    if( defined $props {$attr} ) {
        return $props {$attr} -> { refaddr $self};
    }
    # otherwise, carp a warning
    else {
        carp("Invalid attribute '$attr'");
    }
}