From e9f43a54fc2653220a4da6272ce060775928fa67 Mon Sep 17 00:00:00 2001
From: Michael Mandl <mandlm@molez.net>
Date: Fri, 25 Mar 2016 16:54:43 +0100
Subject: [PATCH] Tutorial files

---
 luhn.lhs | 13 +++++++++++++
 test.lhs | 13 +++++++++++++
 2 files changed, 26 insertions(+)
 create mode 100644 luhn.lhs
 create mode 100644 test.lhs

diff --git a/luhn.lhs b/luhn.lhs
new file mode 100644
index 0000000..6096209
--- /dev/null
+++ b/luhn.lhs
@@ -0,0 +1,13 @@
+This is an implementation of the Luhn Algorithm. It's used to validate credit card numbers.
+
+> lastDigit :: Integer -> Integer
+> lastDigit n = mod n 10
+
+> dropLastDigit :: Integer -> Integer
+> dropLastDigit n = div n 10
+
+> toRevDigits :: Integer -> [Integer]
+> toRevDigits n
+>   | n < 1     = []
+>   | otherwise = lastDigit(n) : toRevDigits(dropLastDigit(n))
+
diff --git a/test.lhs b/test.lhs
new file mode 100644
index 0000000..928cf31
--- /dev/null
+++ b/test.lhs
@@ -0,0 +1,13 @@
+
+Compute the factorial of a given integer number n.
+
+> fac :: Integer -> Integer
+> fac 0 = 1
+> fac n = n * fac(n-1)
+
+Compute the sum of of all integer numbers from 1 to n.
+
+> sumTo :: Integer -> Integer
+> sumTo 0 = 0
+> sumTo n = n + sumTo(n-1)
+