json parse example about Data.Aeson

aeson-example.hs

{-# LANGUAGE OverloadedStrings #-}

-- need to "cabal install aeson"

import Data.Aeson
import qualified Data.Attoparsec as AP
import qualified Data.ByteString.Lazy.Char8 as LC

main = putStrLn $ LC.unpack $ encode $ forceEither $ AP.parseOnly json "{\"foo\":5}"

forceEither :: Show e => Either e a -> a
forceEither (Left x) = error (show x)
forceEither (Right x) = x