diff --git a/pcf.cabal b/pcf.cabal
--- a/pcf.cabal
+++ b/pcf.cabal
@@ -1,5 +1,5 @@
 name:                pcf
-version:             0.1.0.0
+version:             0.1.0.1
 synopsis:            A one file compiler for PCF
 description:         PCF is a small programming language with higher order
                      functions, natural numbers, and recursion. It is
diff --git a/src/Language/Pcf.hs b/src/Language/Pcf.hs
--- a/src/Language/Pcf.hs
+++ b/src/Language/Pcf.hs
@@ -286,9 +286,9 @@
 output :: Exp Integer -> IO (Maybe String)
 output e = case compile e of
   Nothing -> return Nothing
-  Just p  -> Just $ do
+  Just p  -> do
     rts <- getDataFileName "src/preamble.c" >>= readFile
-    return . Just $ rts ++ '\n' : pretty p
+    return . Just $ rts ++ '\n' : show (pretty p)
 
 
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