pituicat/src/Affection/MessageBus/Class.hs
2017-12-20 02:00:48 +01:00

67 lines
1.7 KiB
Haskell

{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE AllowAmbiguousTypes #-}
{-# LANGUAGE ExistentialQuantification #-}
module Affection.MessageBus.Class
( Participant(..)
, genUUID
, UUID
, MsgId(..)
) where
import Affection.MessageBus.Message
import Affection.Types
import Control.Monad.IO.Class (liftIO)
import Data.UUID
import Data.UUID.V4
import Affection.Logging
class (Message msg, Show msg) => Participant prt msg us where
-- | Function to get the list of subscribers from the participant
partSubscribers
:: prt
-- ^ the 'Participant''s subscriber storage
-> Affection us [msg -> Affection us ()]
-- ^ List of Subscriber functions
-- | Subscribe to the 'Participant''s events
partSubscribe
:: prt
-- ^ The 'Participant''s subscriber storage
-> (msg -> Affection us ())
-- ^ What to do in case of a 'Message'
-- (Subscriber function)
-> Affection us (MsgId msg)
-- ^ 'UUID' of the registered subscriber Function
-- | Unsubscribe a Subscriber function from Participant
partUnSubscribe
:: prt
-- ^ The 'Participant''s subscriber storage to unsubscribe from
-> (MsgId msg)
-- ^ The subscriber function's 'UUID'
-> Affection us ()
-- | Get the 'Participant' to emit a 'Message' on all of its subscribers
partEmit
:: prt
-- ^ The 'Participant''s subscriber storage
-> msg
-- ^ The 'Message' to emit
-> Affection us ()
partEmit p m = do
liftIO $ logIO Debug $ "Emitting message: " ++ show m
l <- partSubscribers p
mapM_ ($ m) l
-- | Helper function to generate new 'UUID's
genUUID :: Affection us UUID
genUUID = liftIO nextRandom
data MsgId msg = (Message msg, Show msg) => MsgId UUID msg