+ my $same_query = 'SELECT DISTINCT taxclass FROM cust_main_county '.
+ ' WHERE taxnum != ? AND country = ?';
+ my @same_param = ( 'taxnum', 'country' );
+ foreach my $opt_field (qw( state county )) {
+ if ( $self->$opt_field() ) {
+ $same_query .= " AND $opt_field = ?";
+ push @same_param, $opt_field;
+ } else {
+ $same_query .= " AND $opt_field IS NULL";
+ }
+ }
+
+ my @taxclasses = $self->_list_sql( \@same_param, $same_query );
+
+ return '' unless scalar(@taxclasses);
+
+ '( taxclass IS NULL OR ( '. #only if !$self->taxclass ??
+ join(' AND ', map { 'taxclass != '.dbh->quote($_) } @taxclasses ).
+ ' ) ) ';
+}
+
+sub _list_sql {
+ my( $self, $param, $sql ) = @_;
+ my $sth = dbh->prepare($sql) or die dbh->errstr;
+ $sth->execute( map $self->$_(), @$param )
+ or die "Unexpected error executing statement $sql: ". $sth->errstr;
+ map $_->[0], @{ $sth->fetchall_arrayref };
+}
+
+=item taxline TAXABLES_ARRAYREF, [ OPTION => VALUE ... ]
+
+Takes an arrayref of L<FS::cust_bill_pkg> objects representing taxable
+line items, and returns a new L<FS::cust_bill_pkg> object representing
+the tax on them under this tax rate.
+
+This will have a pseudo-field, "cust_bill_pkg_tax_location", containing
+an arrayref of L<FS::cust_bill_pkg_tax_location> objects. Each of these
+will in turn have a "taxable_cust_bill_pkg" pseudo-field linking it to one
+of the taxable items. All of these links must be resolved as the objects
+are inserted.
+
+In addition to calculating the tax for the line items, this will calculate
+any appropriate tax exemptions and attach them to the line items.
+
+Options may include 'custnum' and 'invoice_date' in case the cust_bill_pkg
+objects belong to an invoice that hasn't been inserted yet.
+
+Options may include 'exemptions', an arrayref of L<FS::cust_tax_exempt_pkg>
+objects belonging to the same customer, to be counted against the monthly
+tax exemption limit if there is one.
+
+=cut
+
+# XXX change tax_rate.pm to work like this
+
+sub taxline {
+ my( $self, $taxables, %opt ) = @_;
+ return 'taxline called with no line items' unless @$taxables;
+