diff --git a/Text/PrettyPrint/Mainland.hs b/Text/PrettyPrint/Mainland.hs
--- a/Text/PrettyPrint/Mainland.hs
+++ b/Text/PrettyPrint/Mainland.hs
@@ -1,11 +1,3 @@
-{-# LANGUAGE BangPatterns #-}
-{-# LANGUAGE CPP #-}
-{-# LANGUAGE DeriveDataTypeable #-}
-{-# LANGUAGE FlexibleInstances #-}
-{-# LANGUAGE OverlappingInstances #-}
-{-# LANGUAGE TypeSynonymInstances #-}
-{-# LANGUAGE UndecidableInstances #-}
-
 -- Copyright (c) 2006-2012
 --         The President and Fellows of Harvard College.
 --
@@ -56,6 +48,10 @@
 -- #line pragmas.
 --------------------------------------------------------------------------------
 
+{-# LANGUAGE BangPatterns #-}
+{-# LANGUAGE CPP #-}
+{-# LANGUAGE OverlappingInstances #-}
+
 module Text.PrettyPrint.Mainland (
     -- * The document type
     Doc,
@@ -110,6 +106,7 @@
 import qualified Data.Set as Set
 import Data.Symbol
 import Data.Word
+import GHC.Real (Ratio(..))
 
 infixr 5 </>, <+/>, <//>
 infixr 6 <+>
@@ -568,18 +565,20 @@
     fits  !w  (RPos _ x)       = fits w x
     fits  !_  (RLine _ _)      = True
 
-#if MIN_VERSION_base(4,5,0)
-#else
+#if !MIN_VERSION_base(4,5,0)
 infixr 6 <>
 
 (<>) :: Doc -> Doc -> Doc
 x <> y = x `Cat` y
-#endif
+#endif /* !MIN_VERSION_base(4,5,0) */
 
 instance Monoid Doc where
     mempty  = empty
     mappend = Cat
 
+instance Show Doc where
+    showsPrec _ = prettyS 80
+
 class Pretty a where
     ppr     :: a -> Doc
     pprPrec :: Int -> a -> Doc
@@ -601,9 +600,16 @@
 instance Pretty Double where
     ppr = text . show
 
-instance Pretty Rational where
-    ppr = text . show
+ratioPrec, ratioPrec1 :: Int
+ratioPrec  = 7  -- Precedence of ':%' constructor
+ratioPrec1 = ratioPrec + 1
 
+instance (Integral a, Pretty a) => Pretty (Ratio a)  where
+    {-# SPECIALIZE instance Pretty Rational #-}
+    pprPrec p (x:%y) =
+        parensIf (p > ratioPrec) $
+        pprPrec ratioPrec1 x <+> char '%' <+> pprPrec ratioPrec1 y
+
 instance Pretty Bool where
     ppr = text . show
 
@@ -629,12 +635,6 @@
 instance Pretty a => Pretty (Maybe a) where
     pprPrec _ Nothing  = empty
     pprPrec p (Just a) = pprPrec p a
-
-instance Show Doc where
-    showsPrec _ = prettyS 80
-
-instance Pretty a => Show a where
-    showsPrec p = showsPrec p . ppr
 
 instance Pretty Symbol where
     ppr = text . unintern
diff --git a/mainland-pretty.cabal b/mainland-pretty.cabal
--- a/mainland-pretty.cabal
+++ b/mainland-pretty.cabal
@@ -1,5 +1,5 @@
 name:           mainland-pretty
-version:        0.1.2.0
+version:        0.1.3.0
 cabal-version:  >= 1.6
 license:        BSD3
 license-file:   LICENSE