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|
{-# LANGUAGE DeriveGeneric, FlexibleInstances #-}
module Types (
module Types,
Val(..)
) where
import Val
import GHC.Generics (Generic)
import Data.Aeson
-- | Things that the developer sees.
data Seen = Seen
{ seenData :: Val
}
deriving (Show, Generic)
instance ToJSON Seen
instance FromJSON Seen
-- | Things that the developer enters.
data Entered = Entered
{ enteredData :: Val
, echoData :: Val
-- ^ Data that is expected to be Seen, but has not been received
-- at the time this was entered.
}
deriving (Show, Generic)
instance ToJSON Entered
instance FromJSON Entered
-- | An activity (either Entered or Seen) with a pointer
-- to the Activity before this one.
--
-- The Signature is over both the data in the activity, and its pointer.
data Activity a = Activity
{ activity :: a
, prevActivity :: (Maybe HashPointer)
, signature :: Signature
}
deriving (Show, Generic)
instance ToJSON (Activity Seen)
instance FromJSON (Activity Seen)
instance ToJSON (Activity Entered)
instance FromJSON (Activity Entered)
newtype Signature = Signature Val
deriving (Show, Generic)
instance ToJSON Signature
instance FromJSON Signature
-- | A hash pointer to something that hashes to this value.
data HashPointer = HashPointer
{ hashMethod :: HashMethod
, hashValue :: Val
}
deriving (Show, Generic, Eq)
instance ToJSON HashPointer
instance FromJSON HashPointer
-- | We use SHA256. (SHA3 is included to future proof, and because it
-- improves the generated JSON.)
data HashMethod = SHA256 | SHA3
deriving (Show, Generic, Eq)
instance ToJSON HashMethod
instance FromJSON HashMethod
|
