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Luhn test of credit card numbers: Difference between revisions
→{{header|TXR}}: Added.
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1234567812345670 true
</pre>
=={{header|TXR}}==
<lang txr>@(do (defun luhn (num)
(for ((i 1) (sum 0))
((not (zerop num)) (zerop (mod sum 10)))
((inc i) (set num (trunc num 10)))
(let ((dig (mod num 10)))
(if (oddp i)
(inc sum dig)
(let ((dig2 (* 2 dig)))
(inc sum (+ (trunc dig2 10) (mod dig2 10)))))))))
@(collect :vars nil)
@{ccnumber /[0-9]+/}
@(output)
@ccnumber -> @(if (luhn (int-str ccnumber 10)) "good" "bad")
@(end)
@(end)</lang>
<pre>$ txr luhn.txr luhn.txt
49927398716 -> good
49927398717 -> bad
1234567812345678 -> bad
1234567812345670 -> good</pre>
=={{header|Ursala}}==
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