RMCA/Auxiliary/RV.hs

   1 {-# LANGUAGE ScopedTypeVariables #-}
   2
   3 module RMCA.Auxiliary.RV where
   4
   5 import Data.CBMVar
   6 import Data.ReactiveValue
   7
   8 newCBMVarRW :: forall a. a -> IO (ReactiveFieldReadWrite IO a)
   9 newCBMVarRW val = do
  10   mvar <- newCBMVar val
  11   let getter :: IO a
  12       getter = readCBMVar mvar
  13       setter :: a -> IO ()
  14       setter = writeCBMVar mvar
  15       notifier :: IO () -> IO ()
  16       notifier = installCallbackCBMVar mvar
  17   return $ ReactiveFieldReadWrite setter getter notifier
  18
  19 emptyRW :: (Monoid b, ReactiveValueReadWrite a b m) => a -> m b
  20 emptyRW rv = do
  21   val <- reactiveValueRead rv
  22   reactiveValueWrite rv mempty
  23   return val
  24
  25 emptyW :: (Monoid b, ReactiveValueWrite a b m) => a -> m ()
  26 emptyW rv = reactiveValueWrite rv mempty