Safe Haskell	Trustworthy
Language	Haskell98

FRP.Reactivity.Measurement

Description

The elements of FRP.

Synopsis

Documentation

data Measurement t Source #

Measurements are a basic building block for pull-based FRP. They are like futures in that: when you have something running on a separate thread, you can use a Measurement to wait on it. They also establish a measurement of an an event occurrence time. Primitives for Measurements, make this measurement inside an STM (software transactional memory) block. The STM system induces a global time ordering of transactions. I piggyback on top of this mechanism to get a global time ordering of measurement as well. This is an attempt to answer the tricky question of how to measure.

Constructors

Empty

Instances

Monad Measurement Source #
Methods (>>=) :: Measurement a -> (a -> Measurement b) -> Measurement b # (>>) :: Measurement a -> Measurement b -> Measurement b # return :: a -> Measurement a # fail :: String -> Measurement a #
Functor Measurement Source #
Methods fmap :: (a -> b) -> Measurement a -> Measurement b # (<$) :: a -> Measurement b -> Measurement a #
Applicative Measurement Source #
Methods pure :: a -> Measurement a # (<>) :: Measurement (a -> b) -> Measurement a -> Measurement b # (>) :: Measurement a -> Measurement b -> Measurement b # (<*) :: Measurement a -> Measurement b -> Measurement a #
Alternative Measurement Source #
Methods empty :: Measurement a # (<\|>) :: Measurement a -> Measurement a -> Measurement a # some :: Measurement a -> Measurement [a] # many :: Measurement a -> Measurement [a] #
MonadPlus Measurement Source #
Methods mzero :: Measurement a # mplus :: Measurement a -> Measurement a -> Measurement a #
Eq t => Eq (Measurement t) Source #
Methods (==) :: Measurement t -> Measurement t -> Bool # (/=) :: Measurement t -> Measurement t -> Bool #
Show t => Show (Measurement t) Source #
Methods showsPrec :: Int -> Measurement t -> ShowS # show :: Measurement t -> String # showList :: [Measurement t] -> ShowS #
Monoid (Measurement t) Source #
Methods mempty :: Measurement t # mappend :: Measurement t -> Measurement t -> Measurement t # mconcat :: [Measurement t] -> Measurement t #

wait :: Measurement t -> IO () Source #

stmAction :: Measurement t -> STM (Maybe (t, POSIXTime)) Source #

assertMeasurement :: IO (t, POSIXTime) -> IO (Measurement t) Source #

measure :: IO t -> IO (Measurement t) Source #

await :: POSIXTime -> IO (Measurement ()) Source #

Wait for a time, then measure that time.

blindAwait :: POSIXTime -> Measurement () Source #

Give the parameter time as the time of the measurement. This is "blind" to system lags that may disrupt the timing of a control signal.

fromList :: [(t, POSIXTime)] -> [Measurement t] Source #

assertChan :: forall t. IO (t -> POSIXTime -> IO (), [Measurement t]) Source #

chan :: IO (t -> IO (), [Measurement t]) Source #

first :: Measurement t -> Measurement t -> Measurement t Source #

Decide which of the Measurements comes first. I rely on the STM subsystem to find a consistent ordering.

leMeas :: Measurement t -> Measurement u -> Bool Source #

mergeStreams :: [Measurement a] -> [Measurement a] -> [Measurement a] Source #

getValue :: Measurement t -> IO (t, POSIXTime) Source #

Extract value and time of the measurement.

copoint :: Measurement t -> t Source #

time :: Measurement t -> POSIXTime Source #