{-# LANGUAGE DeriveAnyClass #-}

{-# LANGUAGE DeriveGeneric #-}

module Reflection where

import Data.Aeson (FromJSON, ToJSON)

import GHC.Generics

--import JsonPersistence -- use this to use JSON serialization/deserialization

import SimplePersistence (Id, Entity, getId, persist, retrieve)

data User = User {

userId :: Id

, name :: String

, email :: String

} deriving (Show, Read, Generic, ToJSON, FromJSON)

instance Entity User where

getId = userId

data Post = Post {

postId :: Id

, userRef :: Id

, text :: String

} deriving (Show, Read, Generic, ToJSON, FromJSON)

instance Entity Post where

getId = postId

retrieveUser :: Id -> IO User

retrieveUser = retrieve

retrievePost :: Id -> IO Post

retrievePost = retrieve

reflectionDemo = do

putStrLn "Reflection"

let user = User "1" "Heinz Meier" "[email protected]"

let post = Post "4711" "1" "My name is Heinz, this is my first post"

persist user

persist post

user' <- retrieve "1" :: IO User

user' <- retrieveUser "1"

print user'

retrievePost "4711" >>= print