From 5bdaa1e4ffe40add10f000ee993e6b500c419a37 Mon Sep 17 00:00:00 2001
From: Joe Zhao <ztuowen@gmail.com>
Date: Sat, 9 Aug 2014 10:58:03 +0800
Subject: add files from home for previous chapters and sandboxes

---
 pole.hs | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)
 create mode 100644 pole.hs

(limited to 'pole.hs')

diff --git a/pole.hs b/pole.hs
new file mode 100644
index 0000000..4ec54d4
--- /dev/null
+++ b/pole.hs
@@ -0,0 +1,27 @@
+type Birds = Int
+type Pole = (Birds, Birds)
+
+landLeft :: Birds -> Pole -> Maybe Pole
+landLeft n (left, right)
+    | abs((left+n) - right) < 4 = Just (left + n, right)
+    | otherwise                 = Nothing
+
+landRight :: Birds -> Pole -> Maybe Pole
+landRight n (left, right) 
+    | abs((right+n) - left) < 4 = Just (left, right + n)
+    | otherwise                 = Nothing
+
+foo = do
+    x <- Just 3
+    y <- Just "!"
+    Just (show x ++ y)
+
+routine = do
+    start <- return (0,0)
+    first <- landLeft 2 start
+    second <- landRight 2 first
+    landLeft 1 second
+
+wopwop = do
+    (x:xs) <- Just ""
+    return x
-- 
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