1Algorithm::CheckDigits:U:sMe2r3_C0o0n2t(r3i)buted Perl DAolcguomreintthamt:i:oCnheckDigits::M23_002(3)
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NAME

6       CheckDigits::M23_002 - compute check digits for Tax Identification
7       Number (IE)
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SYNOPSIS

10         use Algorithm::CheckDigits;
11
12         $dni = CheckDigits('tin_ie');
13
14         if ($dni->is_valid('8473625E')) {
15               # do something
16         }
17
18         $cn = $dni->complete('1234567.W');
19         # $cn = '1234567TW'
20
21         $cd = $dni->checkdigit('1234577IA');
22         # $cd = 'I'
23
24         $bn = $dni->basenumber('1234577WW');
25         # $bn = '1234577.W'
26

DESCRIPTION

28   ALGORITHM
29       The irish TIN (Tax Identification Number) or VAT Regstration Number
30       consists of 7 digits, a letter in the range from 'A' - 'W' as checksum,
31       and an optionally letter in the range from 'A' - 'I' or the letter 'W'.
32
33       1.  In reverse order, each digit is multiplied by a weight started at
34           2.  (i.e. the number left from the check digit is multiplied with
35           2, the next with 3 and so on).
36
37       2.  If there is an optional letter following the checksum letter
38           (position 9), this letter is mapped to a numeric value based on the
39           following mapping: "A" = 1, "B" = 2, ... "H" = 8, "I" = 9. "W" or
40           absence of this letter means a value of 0. This numeric value is
41           multiplied with 9.
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43       3.  All products from step 1 and 2 are added.
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45       4.  The check digit is the sum from step 3 modulo 23. This number is
46           expressed as the corresponding letter from the alphabet where A-V
47           correspond to 1-22 and W stands for check digit 0.
48
49   METHODS
50       is_valid($number)
51           Returns true only if $number complies with the rules given above
52           and there is a valid check digit at position eight.
53
54           Returns false otherwise,
55
56       complete($number)
57           The check digit for $number is computed and inserted at position
58           eight of $number.
59
60           Returns the complete number with check digit or '' if $number does
61           not consist solely of digits and an optional letter at position
62           nine.
63
64       basenumber($number)
65           Returns the basenumber of $number if $number has a valid check
66           digit. As a placeholder for the checksum a point ('.') is inserted
67           at position eight when the checksum contains the optional letter at
68           position nine.
69
70           Return '' otherwise.
71
72       checkdigit($number)
73           Returns the checkdigit of $number if $number has a valid check
74           digit.
75
76           Return '' otherwise.
77
78   EXPORT
79       None by default.
80

AUTHOR

82       Mathias Weidner, "<mamawe@cpan.org>"
83

SEE ALSO

85       perl, CheckDigits, https://ec.europa.eu/taxation_customs/tin/
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89perl v5.32.1                      2021-01-26Algorithm::CheckDigits::M23_002(3)
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