NAME

       CheckDigits::M89_001 - compute check digits for VAT Registration Number (LU)

SYNOPSIS

         use Algorithm::CheckDigits;

         $ustid = CheckDigits('ustid_lu');

         if ($ustid->is_valid('13669580')) {
               # do something
         }

         $cn = $ustid->complete('136695');
         # $cn = '13669580'

         $cd = $ustid->checkdigit('13669580');
         # $cd = '80'

         $bn = $ustid->basenumber('13669580');
         # $bn = '136695'

DESCRIPTION

   ALGORITHM
       1.  The checksum is the whole number taken modulo 89.

   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

       perl, CheckDigits, www.pruefziffernberechnung.de.