aivika-transformers-2.0: Simulation/Aivika/Trans/Internal/Signal.hs
-- |
-- Module : Simulation.Aivika.Trans.Internal.Signal
-- Copyright : Copyright (c) 2009-2014, David Sorokin <david.sorokin@gmail.com>
-- License : BSD3
-- Maintainer : David Sorokin <david.sorokin@gmail.com>
-- Stability : experimental
-- Tested with: GHC 7.8.3
--
-- This module defines the signal which we can subscribe handlers to.
-- These handlers can be disposed. The signal is triggered in the
-- current time point actuating the corresponded computations from
-- the handlers.
--
module Simulation.Aivika.Trans.Internal.Signal
(-- * Handling and Triggering Signal
Signal(..),
handleSignal_,
SignalSource,
newSignalSource,
publishSignal,
triggerSignal,
-- * Useful Combinators
mapSignal,
mapSignalM,
apSignal,
filterSignal,
filterSignalM,
emptySignal,
merge2Signals,
merge3Signals,
merge4Signals,
merge5Signals,
-- * Signal Arriving
arrivalSignal,
-- * Creating Signal in Time Points
newSignalInTimes,
newSignalInIntegTimes,
newSignalInStartTime,
newSignalInStopTime,
-- * Signal History
SignalHistory,
signalHistorySignal,
newSignalHistory,
newSignalHistoryStartingWith,
readSignalHistory,
-- * Signalable Computations
Signalable(..),
signalableChanged,
emptySignalable,
appendSignalable) where
import Data.Monoid
import Data.List
import Data.Array
import Control.Monad
import Control.Monad.Trans
import Simulation.Aivika.Trans.Session
import Simulation.Aivika.Trans.ProtoRef
import qualified Simulation.Aivika.Trans.Vector as V
import qualified Simulation.Aivika.Trans.Vector.Unboxed as UV
import Simulation.Aivika.Trans.Comp
import Simulation.Aivika.Trans.Internal.Specs
import Simulation.Aivika.Trans.Internal.Parameter
import Simulation.Aivika.Trans.Internal.Simulation
import Simulation.Aivika.Trans.Internal.Event
import Simulation.Aivika.Arrival (Arrival(..))
-- | The signal source that can publish its signal.
data SignalSource m a =
SignalSource { publishSignal :: Signal m a,
-- ^ Publish the signal.
triggerSignal :: a -> Event m ()
-- ^ Trigger the signal actuating
-- all its handlers at the current
-- simulation time point.
}
-- | The signal that can have disposable handlers.
data Signal m a =
Signal { handleSignal :: (a -> Event m ()) -> Event m (DisposableEvent m)
-- ^ Subscribe the handler to the specified
-- signal and return a nested computation
-- within a disposable object that, being applied,
-- unsubscribes the handler from this signal.
}
-- | The queue of signal handlers.
data SignalHandlerQueue m a =
SignalHandlerQueue { queueList :: ProtoRef m [SignalHandler m a] }
-- | It contains the information about the disposable queue handler.
data SignalHandler m a =
SignalHandler { handlerComp :: a -> Event m (),
handlerMarker :: SessionMarker m }
instance SessionMonad m => Eq (SignalHandler m a) where
{-# INLINE (==) #-}
x == y = (handlerMarker x) == (handlerMarker y)
-- | Subscribe the handler to the specified signal forever.
-- To subscribe the disposable handlers, use function 'handleSignal'.
handleSignal_ :: MonadComp m => Signal m a -> (a -> Event m ()) -> Event m ()
{-# INLINE handleSignal_ #-}
handleSignal_ signal h =
do x <- handleSignal signal h
return ()
-- | Create a new signal source.
newSignalSource :: MonadComp m => Simulation m (SignalSource m a)
newSignalSource =
Simulation $ \r ->
do let s = runSession r
list <- newProtoRef s []
let queue = SignalHandlerQueue { queueList = list }
signal = Signal { handleSignal = handle }
source = SignalSource { publishSignal = signal,
triggerSignal = trigger }
handle h =
Event $ \p ->
do m <- newSessionMarker s
x <- enqueueSignalHandler queue h m
return $
DisposableEvent $
Event $ \p -> dequeueSignalHandler queue x
trigger a =
Event $ \p -> triggerSignalHandlers queue a p
return source
-- | Trigger all next signal handlers.
triggerSignalHandlers :: MonadComp m => SignalHandlerQueue m a -> a -> Point m -> m ()
triggerSignalHandlers q a p =
do hs <- readProtoRef (queueList q)
forM_ hs $ \h ->
invokeEvent p $ handlerComp h a
-- | Enqueue the handler and return its representative in the queue.
enqueueSignalHandler :: MonadComp m => SignalHandlerQueue m a -> (a -> Event m ()) -> SessionMarker m -> m (SignalHandler m a)
enqueueSignalHandler q h m =
do let handler = SignalHandler { handlerComp = h,
handlerMarker = m }
modifyProtoRef (queueList q) (handler :)
return handler
-- | Dequeue the handler representative.
dequeueSignalHandler :: MonadComp m => SignalHandlerQueue m a -> SignalHandler m a -> m ()
dequeueSignalHandler q h =
modifyProtoRef (queueList q) (delete h)
instance MonadComp m => Functor (Signal m) where
{-# INLINE fmap #-}
fmap = mapSignal
instance MonadComp m => Monoid (Signal m a) where
{-# INLINE mempty #-}
mempty = emptySignal
{-# INLINE mappend #-}
mappend = merge2Signals
{-# INLINE mconcat #-}
mconcat [] = emptySignal
mconcat [x1] = x1
mconcat [x1, x2] = merge2Signals x1 x2
mconcat [x1, x2, x3] = merge3Signals x1 x2 x3
mconcat [x1, x2, x3, x4] = merge4Signals x1 x2 x3 x4
mconcat [x1, x2, x3, x4, x5] = merge5Signals x1 x2 x3 x4 x5
mconcat (x1 : x2 : x3 : x4 : x5 : xs) =
mconcat $ merge5Signals x1 x2 x3 x4 x5 : xs
-- | Map the signal according the specified function.
mapSignal :: MonadComp m => (a -> b) -> Signal m a -> Signal m b
mapSignal f m =
Signal { handleSignal = \h ->
handleSignal m $ h . f }
-- | Filter only those signal values that satisfy to
-- the specified predicate.
filterSignal :: MonadComp m => (a -> Bool) -> Signal m a -> Signal m a
filterSignal p m =
Signal { handleSignal = \h ->
handleSignal m $ \a ->
when (p a) $ h a }
-- | Filter only those signal values that satisfy to
-- the specified predicate.
filterSignalM :: MonadComp m => (a -> Event m Bool) -> Signal m a -> Signal m a
filterSignalM p m =
Signal { handleSignal = \h ->
handleSignal m $ \a ->
do x <- p a
when x $ h a }
-- | Merge two signals.
merge2Signals :: MonadComp m => Signal m a -> Signal m a -> Signal m a
merge2Signals m1 m2 =
Signal { handleSignal = \h ->
do x1 <- handleSignal m1 h
x2 <- handleSignal m2 h
return $ x1 <> x2 }
-- | Merge three signals.
merge3Signals :: MonadComp m => Signal m a -> Signal m a -> Signal m a -> Signal m a
merge3Signals m1 m2 m3 =
Signal { handleSignal = \h ->
do x1 <- handleSignal m1 h
x2 <- handleSignal m2 h
x3 <- handleSignal m3 h
return $ x1 <> x2 <> x3 }
-- | Merge four signals.
merge4Signals :: MonadComp m
=> Signal m a -> Signal m a -> Signal m a
-> Signal m a -> Signal m a
merge4Signals m1 m2 m3 m4 =
Signal { handleSignal = \h ->
do x1 <- handleSignal m1 h
x2 <- handleSignal m2 h
x3 <- handleSignal m3 h
x4 <- handleSignal m4 h
return $ x1 <> x2 <> x3 <> x4 }
-- | Merge five signals.
merge5Signals :: MonadComp m
=> Signal m a -> Signal m a -> Signal m a
-> Signal m a -> Signal m a -> Signal m a
merge5Signals m1 m2 m3 m4 m5 =
Signal { handleSignal = \h ->
do x1 <- handleSignal m1 h
x2 <- handleSignal m2 h
x3 <- handleSignal m3 h
x4 <- handleSignal m4 h
x5 <- handleSignal m5 h
return $ x1 <> x2 <> x3 <> x4 <> x5 }
-- | Compose the signal.
mapSignalM :: MonadComp m => (a -> Event m b) -> Signal m a -> Signal m b
mapSignalM f m =
Signal { handleSignal = \h ->
handleSignal m (f >=> h) }
-- | Transform the signal.
apSignal :: MonadComp m => Event m (a -> b) -> Signal m a -> Signal m b
apSignal f m =
Signal { handleSignal = \h ->
handleSignal m $ \a -> do { x <- f; h (x a) } }
-- | An empty signal which is never triggered.
emptySignal :: MonadComp m => Signal m a
emptySignal =
Signal { handleSignal = \h -> return mempty }
-- | Represents the history of the signal values.
data SignalHistory m a =
SignalHistory { signalHistorySignal :: Signal m a,
-- ^ The signal for which the history is created.
signalHistoryTimes :: UV.Vector m Double,
signalHistoryValues :: V.Vector m a }
-- | Create a history of the signal values.
newSignalHistory :: MonadComp m => Signal m a -> Event m (SignalHistory m a)
newSignalHistory =
newSignalHistoryStartingWith Nothing
-- | Create a history of the signal values starting with
-- the optional initial value.
newSignalHistoryStartingWith :: MonadComp m => Maybe a -> Signal m a -> Event m (SignalHistory m a)
newSignalHistoryStartingWith init signal =
Event $ \p ->
do let s = runSession $ pointRun p
ts <- UV.newVector s
xs <- V.newVector s
case init of
Nothing -> return ()
Just a ->
do UV.appendVector ts (pointTime p)
V.appendVector xs a
invokeEvent p $
handleSignal_ signal $ \a ->
Event $ \p ->
do UV.appendVector ts (pointTime p)
V.appendVector xs a
return SignalHistory { signalHistorySignal = signal,
signalHistoryTimes = ts,
signalHistoryValues = xs }
-- | Read the history of signal values.
readSignalHistory :: MonadComp m => SignalHistory m a -> Event m (Array Int Double, Array Int a)
readSignalHistory history =
Event $ \p ->
do xs <- UV.freezeVector (signalHistoryTimes history)
ys <- V.freezeVector (signalHistoryValues history)
return (xs, ys)
-- | Trigger the signal with the current time.
triggerSignalWithCurrentTime :: MonadComp m => SignalSource m Double -> Event m ()
triggerSignalWithCurrentTime s =
Event $ \p -> invokeEvent p $ triggerSignal s (pointTime p)
-- | Return a signal that is triggered in the specified time points.
newSignalInTimes :: MonadComp m => [Double] -> Event m (Signal m Double)
newSignalInTimes xs =
do s <- liftSimulation newSignalSource
enqueueEventWithTimes xs $ triggerSignalWithCurrentTime s
return $ publishSignal s
-- | Return a signal that is triggered in the integration time points.
-- It should be called with help of 'runEventInStartTime'.
newSignalInIntegTimes :: MonadComp m => Event m (Signal m Double)
newSignalInIntegTimes =
do s <- liftSimulation newSignalSource
enqueueEventWithIntegTimes $ triggerSignalWithCurrentTime s
return $ publishSignal s
-- | Return a signal that is triggered in the start time.
-- It should be called with help of 'runEventInStartTime'.
newSignalInStartTime :: MonadComp m => Event m (Signal m Double)
newSignalInStartTime =
do s <- liftSimulation newSignalSource
t <- liftParameter starttime
enqueueEvent t $ triggerSignalWithCurrentTime s
return $ publishSignal s
-- | Return a signal that is triggered in the final time.
newSignalInStopTime :: MonadComp m => Event m (Signal m Double)
newSignalInStopTime =
do s <- liftSimulation newSignalSource
t <- liftParameter stoptime
enqueueEvent t $ triggerSignalWithCurrentTime s
return $ publishSignal s
-- | Describes a computation that also signals when changing its value.
data Signalable m a =
Signalable { readSignalable :: Event m a,
-- ^ Return a computation of the value.
signalableChanged_ :: Signal m ()
-- ^ Return a signal notifying that the value has changed
-- but without providing the information about the changed value.
}
-- | Return a signal notifying that the value has changed.
signalableChanged :: MonadComp m => Signalable m a -> Signal m a
signalableChanged x = mapSignalM (const $ readSignalable x) $ signalableChanged_ x
instance Functor m => Functor (Signalable m) where
{-# INLINE fmap #-}
fmap f x = x { readSignalable = fmap f (readSignalable x) }
instance (MonadComp m, Monoid a) => Monoid (Signalable m a) where
{-# INLINE mempty #-}
mempty = emptySignalable
{-# INLINE mappend #-}
mappend = appendSignalable
-- | Return an identity.
emptySignalable :: (MonadComp m, Monoid a) => Signalable m a
emptySignalable =
Signalable { readSignalable = return mempty,
signalableChanged_ = mempty }
-- | An associative operation.
appendSignalable :: (MonadComp m, Monoid a) => Signalable m a -> Signalable m a -> Signalable m a
appendSignalable m1 m2 =
Signalable { readSignalable = liftM2 (<>) (readSignalable m1) (readSignalable m2),
signalableChanged_ = (signalableChanged_ m1) <> (signalableChanged_ m2) }
-- | Transform a signal so that the resulting signal returns a sequence of arrivals
-- saving the information about the time points at which the original signal was received.
arrivalSignal :: MonadComp m => Signal m a -> Signal m (Arrival a)
arrivalSignal m =
Signal { handleSignal = \h ->
Event $ \p ->
do let s = runSession $ pointRun p
r <- newProtoRef s Nothing
invokeEvent p $
handleSignal m $ \a ->
Event $ \p ->
do t0 <- readProtoRef r
let t = pointTime p
writeProtoRef r (Just t)
invokeEvent p $
h Arrival { arrivalValue = a,
arrivalTime = t,
arrivalDelay =
case t0 of
Nothing -> Nothing
Just t0 -> Just (t - t0) } }