CheckDigits::M89_001(3) 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'

## 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.

None by default.

## AUTHOR

Mathias Weidner, <[email protected]>