-- | A port of Kris Jenkins' RemoteData Elm module
-- <https://github.com/krisajenkins/remotedata>.
module Network.RemoteData where

data RemoteData a b
  = NotAsked
  | Loading
  | Failure a
  | Success b
  deriving (Eq, Show)

instance Functor (RemoteData a) where
  fmap _ NotAsked = NotAsked
  fmap _ Loading = Loading
  fmap _ (Failure a) = Failure a
  fmap f (Success a) = Success (f a)

instance Applicative (RemoteData e) where
  pure = Success
  NotAsked <*> _ = NotAsked
  Loading <*> _ = Loading
  Failure a <*> _ = Failure a
  Success a <*> b = fmap a b

fromEither :: Either a b -> RemoteData a b
fromEither (Left a) = Failure a
fromEither (Right a) = Success a