Haskell, Aeson & JSON parsing into custom type

Question

Following on from a previous post, I\'ve found I\'m totally stuck. I\'m trying to parse a JSON structure into my own type, and not only am I stuck on how to parse the Array,

Answer 1

I'm not native english speaker, so i may not understand you very well. I guess you want to know how to parse json into recursive data type like ExifValue you presented. So i made a simple example to show how to parse json into recursive data type.

{-# LANGUAGE OverloadedStrings #-}
import qualified Data.ByteString as B
import Data.Maybe
import Control.Monad
import Control.Applicative
import Data.Attoparsec
import Data.Attoparsec.Number
import Data.Aeson
import qualified Data.Vector as V

data Data = D1 Int | D2 [Data]
    deriving (Show)

instance FromJSON Data where
    parseJSON (Number (I n)) = return $ D1 $ fromInteger n
    parseJSON (Array a)    = D2 <$> mapM parseJSON (V.toList a)

main = do
    let v = fromJust $ maybeResult $ parse json "[1,2,3,[5,3,[6,3,5]]]"
    let v1 :: Data
        v1 = case fromJSON v of
                 Success a -> a
                 Error s   -> error s
    print v1