test.hs

{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE OverloadedStrings #-}
import Control.Monad
import Data.Aeson
import qualified Data.ByteString.Lazy as B

{- Generic Language extension -}
import GHC.Generics (Generic)

data Pull = Pull {
    title :: String
    } deriving (Show, Generic)

instance FromJSON Pull
instance ToJSON Pull

main = do
    bstr <- (B.readFile "test.json")
    loop bstr (100 :: Int)
    where 
      loop _ 0 = return ()
      loop bstr n = do
          case decode bstr :: Maybe [Pull] of
              Just ps -> mapM_ (putStrLn . title) ps
              Nothing -> putStr "can't parse test.json"
          loop bstr $ n-1