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Bryan O'Sullivan  committed c4221fe

Make Value an instance of Hashable.

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  • Parent commits 308cd90

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File Data/Aeson/Types.hs

 import Data.Aeson.Functions
 import Data.Attoparsec.Char8 (Number(..))
 import Data.Data (Data)
+import Data.Hashable (Hashable(..))
 import Data.Int (Int8, Int16, Int32, Int64)
+import Data.List (foldl')
 import Data.Map (Map)
 import Data.Monoid (Dual(..), First(..), Last(..))
 import Data.Monoid (Monoid(..))
     fromString = String . pack
     {-# INLINE fromString #-}
 
+instance Hashable Value where
+    hash (Object o) = foldl' hashWithSalt 0 . M.toList $ o
+    hash (Array a)  = V.foldl' hashWithSalt 1 a
+    hash (String s) = 2 `hashWithSalt` s
+    hash (Number n) = 3 `hashWithSalt` case n of I i -> hash i; D d -> hash d
+    hash (Bool b)   = 4 `hashWithSalt` b
+    hash Null       = 5
+
 -- | The empty array.
 emptyArray :: Value
 emptyArray = Array V.empty