• NAME
• SYNOPSIS
• ALGORITHM
• METHODS
• EXPORT
• AUTHOR
• SEE ALSO

NAME

CheckDigits::M23_002 - compute check digits for VAT Registration Number (IE)

SYNOPSIS

  use CheckDigits;

  $dni = CheckDigits('ustid_ie');

  if ($dni->is_valid('8473625E')) {
        # do something
  }

  $cn = $dni->complete('8473625');
  # $cn = '8473625E'

  $cd = $dni->checkdigit('8473625E');
  # $cd = 'E'

  $bn = $dni->basenumber('8473625E');
  # $bn = '8473625'

=head1 DESCRIPTION

ALGORITHM

1. Beginning right all digits are weighted with their position in the number (i.e. the number left from the check digit is multiplied with 2, the next with 3 and so on).

2. All products are added.

3. The check digit is the sum from step 2 modulo 23. This number is expressed as the corresponding letter from the alphabet where A-V correspond to 1-22 and W stands for check digit 0.

METHODS

is_valid($number)

Returns true only if $number consists solely of numbers and the last digit is a valid check digit according to the algorithm given above.

Returns false otherwise,

complete($number)

The check digit for $number is computed and concatenated to the end of $number.

Returns the complete number with check digit or '' if $number does not consist solely of digits and spaces.

basenumber($number)

Returns the basenumber of $number if $number has a valid check digit.

Return '' otherwise.

checkdigit($number)

Returns the checkdigit of $number if $number has a valid check digit.

Return '' otherwise.

EXPORT

None by default.

AUTHOR

Mathias Weidner, <mathias@weidner.in-bad-schmiedeberg.de>

SEE ALSO

the perl manpage, the CheckDigits manpage, www.pruefziffernberechnung.de.