NAME

       CheckDigits::M10_008 - compute check digits for Sedol (GB)

SYNOPSIS

         use Algorithm::CheckDigits;

         $sedol = CheckDigits('sedol');

         if ($sedol->is_valid('0123457')) {
               # do something
         }

         $cn = $sedol->complete('012345');
         # $cn = '0123457'

         $cd = $sedol->checkdigit('0123457');
         # $cd = '7'

         $bn = $sedol->basenumber('0123457');
         # $bn = '012345'

DESCRIPTION

       Prior to March 2004 SEDOL codes solely consisted of numbers. Since March 2004 SEDOL codes
       are a 7 character alphanumeric code.

       The structure of the alphanumeric SEDOL codes is one alpha character followed by 5
       alphanumeric characters followed by the numerical check digit.

       Alpha characters are B-Z excluding vowels.
       Alphanumerical characters are 0-9, B-Z excluding vowels.
       Numerical Characters are 0-9.

       No SEDOL code will be issued without the first alpha character. Active numerical SEDOL
       codes issued prior to March 2004 remain valid.

   ALGORITHM
       0   All characters are assigned a numerical value from 0 to 35 where the characters '0' to
           '9' get 0 to 9, 'B' to 'Z' get 11 to 35 with the position of the vowels kept empty
           (for instance 'D' gets 13, 'F' gets 15).

       1   Beginning left all numbers are weighted with 1,3,1,7,3,9 and 1 (checkdigit)

       2   The sum of all products is computed.

       3   The check digit is the difference of the sum from step 3 to the next multiple of 10.

   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.

           This function always returns the SEDOL code in upper case.

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

           Return '' otherwise.

           This function always returns the SEDOL base number in upper case.

       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.londonstockexchange.com Masterfile technical specifications V7.0.