NAME

CheckDigits::M11_009 - compute check digits NRIC (SG)

SYNOPSIS

  use CheckDigits;

  $nric = CheckDigits('nric_sg');

  if ($nric->is_valid('S1234567D')) {
        # do something
  }

  $cn = $nric->complete('S1234567');
  # $cn = 'S1234567D'

  $cd = $nric->checkdigit('S1234567D');
  # $cd = 'D'

  $bn = $nric->basenumber('S1234567D');
  # $bn = 'S1234567';


=head1 DESCRIPTION

ALGORITHM

Beginning left every digit is weighted with 2, 7, 6, 5, 4, 3, 2
The weighted digits are added.
The sum from step 2 is taken modulo 11.
The checkdigit is 11 minus the sum from step 3 converted to a character according to the following table:
```
  @cd = ('','A','B','C','D','E','F','G','H','I','Z','J', );
```

METHODS

is_valid($number)

Returns true only if $number consists solely of numbers and hyphens and the two digits in the middle are valid check digits according to the algorithm given above.

Returns false otherwise,

complete($number)

The check digit for $number is computed and inserted into the middle of $number.

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

basenumber($number)