Toy Example for decoding JSON from Stdin

Test.hs

{-# LANGUAGE TypeApplications #-}
{-# LANGUAGE OverloadedStrings #-}

module Test where

import           Data.Aeson
import           Data.ByteString.Lazy as BL
import           Data.Text as T

data User = User { name    :: Text
                 , surname :: Text
                 } deriving Show


instance FromJSON User where
  parseJSON =
    withObject "user" $ \obj -> User <$> (obj .: "name") <*> (obj .: "surname")


main :: IO ()
main = BL.getContents >>= print . decode' @User