From 6588473adf96a3eb7cfac55820ec022d4533fcbf Mon Sep 17 00:00:00 2001
From: Joe Zhao <ztuowen@gmail.com>
Date: Mon, 24 Aug 2015 15:45:45 -0600
Subject: Foldables

---
 monad/h3.hs | 11 +++++++++++
 1 file changed, 11 insertions(+)
 create mode 100644 monad/h3.hs

(limited to 'monad/h3.hs')

diff --git a/monad/h3.hs b/monad/h3.hs
new file mode 100644
index 0000000..9439331
--- /dev/null
+++ b/monad/h3.hs
@@ -0,0 +1,11 @@
+data Free f a = Var a
+              | Node (f (Free f a))
+
+instance Functor f => Functor (Free f) where
+    fmap g (Var a) = g a
+    fmap g (Node a) = fmap g a
+
+instance Functor f => Monad (Free f) where
+    return a = Var a
+    (Var a) >>= g = g a
+    (Node a) >>= g = fmap g a
-- 
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