Business::ID::NPWP is a Perl module that can be used to validate Indonesian taxpayer registration number, Nomor Pokok Wajib Pajak (NPWP).
NPWP is composed of 15 digits as follow:
S is a serial number from 0-9 (so far haven't seen 7 and up, but it's probably possible).
T denotes taxpayer type code (0 = government treasury [bendahara pemerintah], 1-3 = company/organization [badan], 4/6 = invidual entrepreneur [pengusaha perorangan], 5 = civil servants [pegawai negeri, PNS], 7-9 = individual employee [pegawai perorangan]).
sss.sss is a 6-digit serial code for the taxpayer, probably starts from 1. It is distributed in blocks by the central tax office (kantor pusat dirjen pajak, DJP) to the local tax offices (kantor pelayanan pajak, KPP) throughout the country for allocation to taypayers.
C is a check digit. It is apparently using Luhn (modulus 10) algorithm on the first 9 digits on the NPWP.
OOO is a 3-digit local tax office code (kode KPP).
BBB is a 3-digit branch code. 000 means the taxpayer is the sole branch (or, for individuals, the head of the family). 001, 002, and so on denote each branch.
my $npwp = Business::ID::NPWP->new($str);
die "Invalid NPWP!" unless $npwp->validate;
print $npwp->taxpayer_code, "\n"; # also, kode_wajib_pajak()
print $npwp->serial, "\n"; # also, nomor_urut()
print $npwp->check_digit, "\n";
print $npwp->local_tax_office_code, "\n"; # also, kode_kpp()
print $npwp->branch_code, "\n"; # also, kode_cabang()
# procedural style
validate_npwp($str) or die "Invalid NPWP!";