diff --git a/Data/Aeson/AutoType/Alternative.hs b/Data/Aeson/AutoType/Alternative.hs
--- a/Data/Aeson/AutoType/Alternative.hs
+++ b/Data/Aeson/AutoType/Alternative.hs
@@ -1,31 +1,32 @@
-{-# LANGUAGE ViewPatterns #-}
+{-# LANGUAGE ViewPatterns, TypeOperators #-}
 module Data.Aeson.AutoType.Alternative(
-    Alt(..)
+    (:|:)(..)
   , toEither, fromEither
   ) where
 
 import Data.Aeson
 import Control.Applicative
 
-data Alt a b = FirstAlt  a
-             | SecondAlt b
+data a :|: b = AltLeft  a
+             | AltRight b
   deriving(Show,Eq,Ord)
+infixr 5 :|:
 
-toEither :: Alt a b -> Either a b
-toEither (FirstAlt  a) = Left  a
-toEither (SecondAlt b) = Right b
+toEither :: a :|: b -> Either a b
+toEither (AltLeft  a) = Left  a
+toEither (AltRight b) = Right b
 
-fromEither :: Either a b -> Alt a b
-fromEither (Left  a) = FirstAlt  a
-fromEither (Right b) = SecondAlt b
+fromEither :: Either a b -> a :|: b
+fromEither (Left  a) = AltLeft  a
+fromEither (Right b) = AltRight b
 
-instance (ToJSON a, ToJSON b) => ToJSON (Alt a b) where
-    toJSON (FirstAlt  a) = toJSON a
-    toJSON (SecondAlt b) = toJSON b
+instance (ToJSON a, ToJSON b) => ToJSON (a :|: b) where
+    toJSON (AltLeft  a) = toJSON a
+    toJSON (AltRight b) = toJSON b
     {-# INLINE toJSON #-}
 
-instance (FromJSON a, FromJSON b) => FromJSON (Alt a b) where
-    parseJSON input = (FirstAlt  <$> parseJSON input) <|>
-                      (SecondAlt <$> parseJSON input) <|>
+instance (FromJSON a, FromJSON b) => FromJSON (a :|: b) where
+    parseJSON input = (AltLeft  <$> parseJSON input) <|>
+                      (AltRight <$> parseJSON input) <|>
                       fail ("Neither alternative was found for: " ++ show input)
     {-# INLINE parseJSON #-}
diff --git a/Data/Aeson/AutoType/CodeGen.hs b/Data/Aeson/AutoType/CodeGen.hs
--- a/Data/Aeson/AutoType/CodeGen.hs
+++ b/Data/Aeson/AutoType/CodeGen.hs
@@ -26,8 +26,11 @@
 
 header :: Text -> Text
 header moduleName = Text.unlines [
-   "{-# LANGUAGE TemplateHaskell, ScopedTypeVariables #-}"
-  ,"{-# LANGUAGE RecordWildCards, OverloadedStrings #-}"
+   "{-# LANGUAGE TemplateHaskell     #-}"
+  ,"{-# LANGUAGE ScopedTypeVariables #-}"
+  ,"{-# LANGUAGE RecordWildCards     #-}"
+  ,"{-# LANGUAGE OverloadedStrings   #-}"
+  ,"{-# LANGUAGE TypeOperators       #-}"
   ,""
   ,Text.concat ["module ", capitalize moduleName, " where"]
   ,""
diff --git a/Data/Aeson/AutoType/Format.hs b/Data/Aeson/AutoType/Format.hs
--- a/Data/Aeson/AutoType/Format.hs
+++ b/Data/Aeson/AutoType/Format.hs
@@ -155,7 +155,7 @@
   where
     mkUnion []       = emptyTypeRepr
     mkUnion nonEmpty = foldr1 mkEither nonEmpty
-      where mkEither a b = Text.concat ["Alt (", a, ") (", b, ")"]
+      where mkEither a b = Text.concat [a, " :|: ", b]
 formatType (TArray a)                        = do inner <- formatType a
                                                   return $ Text.concat ["[", inner, "]"]
 formatType (TObj   o)                        = do ident <- genericIdentifier
diff --git a/json-autotype.cabal b/json-autotype.cabal
--- a/json-autotype.cabal
+++ b/json-autotype.cabal
@@ -1,6 +1,6 @@
 -- Build information for the package.
 name:                json-autotype
-version:             0.2.4.0
+version:             0.2.5.0
 synopsis:            Automatic type declaration for JSON input data
 description:         Generates datatype declarations with Aeson's "FromJSON" instances
                      from a set of example ".json" files.