Algorithm::CheckDigits::M23_002(3)

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

SYNOPSIS
  use Algorithm::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'

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, "<mamawe@cpan.org>"

SEE ALSO
perl, CheckDigits, www.pruefziffernberechnung.de.