Perl module to validate or generate credit card checksums and names

 Business::CreditCard tell you whether a credit card number is
 self-consistent -- whether the last digit of the number is a valid
 checksum for the preceding digits.
 .
 The validate() subroutine returns 1 if the card number provided passes
 the checksum test, and 0 otherwise.
 .
 The cardtype() subroutine returns a string containing the type of
 card: "MasterCard", "VISA", and so on.
 .
 The generate_last_digit() subroutine computes and returns the last
 digit of the card given the preceding digits. With a 16-digit card,
 you provide the first 15 digits; the subroutine returns the sixteenth.