diff --git a/Language/Unlambda.hs b/Language/Unlambda.hs
--- a/Language/Unlambda.hs
+++ b/Language/Unlambda.hs
@@ -1,5 +1,3 @@
-{-# OPTIONS -fglasgow-exts #-}
-
 {-
 Uses pattern guards
 
@@ -51,7 +49,8 @@
 ------------------------------------------------------------------------
 -- Printing
 
-instance Show Exp where showsPrec _ e = sh e
+instance Show Exp where
+  showsPrec _ = sh
 
 sh :: Exp -> String -> String
 sh (App x y)  = showChar '`' . sh x . sh y
@@ -125,14 +124,14 @@
 apply (S2 x y) z = eval (App (App x z) (App y z))
 apply I x        = return x
 apply V _        = return V
-apply C x        = callCC (\c -> apply x (Cont c))
+apply C x        = callCC (apply x . Cont)
 apply (Cont c) x = throw c x
 apply D x        = return x
 apply (D1 e) x   = do f <- eval e; apply f x
 apply (Dot c) x  = step >> io (putChar c) >> return x
 apply E x        = exit x
 apply At f = do
-  dat <- io $ catch (getChar >>= return . Just) (const $ return Nothing)
+  dat <- io $ catch (fmap Just getChar) (const $ return Nothing)
   setCurrentChar dat
   apply f (case dat of Nothing -> V ; Just _  -> I)
 apply (Ques c) f = do
@@ -140,5 +139,5 @@
   apply f (if cur == Just c then I else V)
 apply Pipe f = do
   cur <- currentChar
-  apply f (case cur of Nothing -> V ; Just c  -> (Dot c))
+  apply f (case cur of Nothing -> V ; Just c  -> Dot c)
 apply (App _ _) _ = error "Unknown application"
diff --git a/Main.hs b/Main.hs
--- a/Main.hs
+++ b/Main.hs
@@ -5,11 +5,15 @@
 -- A time- and output-limited unlambda
 
 import System.Posix.Resource
-import Data.Char
-import System.IO
+import Data.Char (toLower)
+import System.IO (hGetChar, hGetLine, stdin, Handle())
 
 import Language.Unlambda
 
+{- WARNING: There is no way this is actually enough sandboxing (mueval has to do
+a heck of a lot more to safely valuate expressions and not all of it
+involves libraries), but since no one seems to be attacking via `unlambda`
+we'll leave this be. -}
 main :: IO Exp
 main = (setResourceLimit ResourceCPUTime $ ResourceLimits (ResourceLimit 5) (ResourceLimit 5)) >> run
 
diff --git a/unlambda.cabal b/unlambda.cabal
--- a/unlambda.cabal
+++ b/unlambda.cabal
@@ -1,5 +1,5 @@
 name:                unlambda
-version:             0.1
+version:             0.1.2
 
 license:             GPL
 license-file:        LICENSE
@@ -14,17 +14,21 @@
                      written in the pure, lazy, functional language Haskell.
 
 build-type:          Simple
-Cabal-Version:       >= 1.2
+Cabal-Version:       >= 1.6
 tested-with:         GHC==6.8.2
 
+source-repository head
+  type:     darcs
+  location: http://code.haskell.org/lambdabot
+
 executable              unlambda
    main-is:             Main.hs
-   build-depends:       base>3, unix
+   build-depends:       base>3 && <5, unix
 
 library
    exposed-modules:     Language.Unlambda
 
-   build-depends:       base, array, mtl
+   build-depends:       base>3 && <5, array, mtl
 
    ghc-options:         -Wall
    ghc-prof-options:    -prof -auto-all