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| -rw-r--r-- | examples.lisp | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/examples.lisp b/examples.lisp new file mode 100644 index 0000000..7bd44e2 --- /dev/null +++ b/examples.lisp @@ -0,0 +1,15 @@ + +(defpackage #:lt-examples + (:use #:cl #:lambda-toosl)) + + +;; http://rosettacode.org/wiki/Luhn_test_of_credit_card_numbers +(defun luhn (n) + (flet ((sum-dig (x) (if (> x 9) (- x 9) x))) + (>> n + #'reverse + ($$ (map 'list #'digit-char-p $char)) + ($$ (mapcar #'* + (loop :for i :upto (length $digits) :collect (1+ (mod i 2))) + $digits)) + ($$ (zerop (mod (apply #'+ (mapcar #'sum-dig $digits)) 10)))))) |