| Safe Haskell | Safe-Inferred |
|---|
FRP.Sodium.Context
Description
Generalization of the Sodium API to allow for parallel processing.
- class (Applicative (Reactive r), Monad (Reactive r), MonadFix (Reactive r), Functor (Event r), Applicative (Behavior r)) => Context r where
- data Reactive r :: * -> *
- data Event r :: * -> *
- data Behavior r :: * -> *
- sync :: Reactive r a -> IO a
- ioReactive :: IO a -> Reactive r a
- newEvent :: Reactive r (Event r a, a -> Reactive r ())
- listen :: Event r a -> (a -> IO ()) -> Reactive r (IO ())
- never :: Event r a
- merge :: Event r a -> Event r a -> Event r a
- filterJust :: Event r (Maybe a) -> Event r a
- hold :: a -> Event r a -> Reactive r (Behavior r a)
- changes :: Behavior r a -> Event r a
- values :: Behavior r a -> Event r a
- snapshotWith :: (a -> b -> c) -> Event r a -> Behavior r b -> Event r c
- switchE :: Behavior r (Event r a) -> Event r a
- switch :: Behavior r (Behavior r a) -> Reactive r (Behavior r a)
- execute :: Event r (Reactive r a) -> Event r a
- sample :: Behavior r a -> Reactive r a
- coalesce :: (a -> a -> a) -> Event r a -> Event r a
- once :: Context r => Event r a -> Event r a
- split :: Event r [a] -> Event r a
- type Behaviour r a = Behavior r a
- newBehavior :: forall r a. Context r => a -> Reactive r (Behavior r a, a -> Reactive r ())
- newBehaviour :: forall r a. Context r => a -> Reactive r (Behavior r a, a -> Reactive r ())
- mergeWith :: Context r => (a -> a -> a) -> Event r a -> Event r a -> Event r a
- filterE :: Context r => (a -> Bool) -> Event r a -> Event r a
- snapshot :: Context r => Event r a -> Behavior r b -> Event r b
- gate :: Context r => Event r a -> Behavior r Bool -> Event r a
- collectE :: Context r => (a -> s -> (b, s)) -> s -> Event r a -> Reactive r (Event r b)
- collect :: Context r => (a -> s -> (b, s)) -> s -> Behavior r a -> Reactive r (Behavior r b)
- accum :: Context r => a -> Event r (a -> a) -> Reactive r (Behavior r a)
- count :: Context r => Event r a -> Reactive r (Behavior r Int)
Documentation
class (Applicative (Reactive r), Monad (Reactive r), MonadFix (Reactive r), Functor (Event r), Applicative (Behavior r)) => Context r whereSource
Associated Types
data Reactive r :: * -> *Source
A stream of events. The individual firings of events are called 'event occurrences'.
data Behavior r :: * -> *Source
A time-varying value, American spelling.
Methods
sync :: Reactive r a -> IO aSource
Execute the specified Reactive within a new transaction, blocking the caller
until all resulting processing is complete and all callbacks have been called.
This operation is thread-safe, so it may be called from any thread.
State changes to hold values occur after processing of the transaction is complete.
ioReactive :: IO a -> Reactive r aSource
newEvent :: Reactive r (Event r a, a -> Reactive r ())Source
Returns an event, and a push action for pushing a value into the event.
listen :: Event r a -> (a -> IO ()) -> Reactive r (IO ())Source
Listen for firings of this event. The returned IO () is an IO action
that unregisters the listener. This is the observer pattern.
To listen to a Behavior use listen (values b) handler
An event that never fires.
merge :: Event r a -> Event r a -> Event r aSource
Merge two streams of events of the same type.
In the case where two event occurrences are simultaneous (i.e. both within the same transaction), both will be delivered in the same transaction. If the event firings are ordered for some reason, then their ordering is retained. In many common cases the ordering will be undefined.
filterJust :: Event r (Maybe a) -> Event r aSource
Unwrap Just values, and discard event occurrences with Nothing values.
hold :: a -> Event r a -> Reactive r (Behavior r a)Source
Create a behavior with the specified initial value, that gets updated by the values coming through the event. The 'current value' of the behavior is notionally the value as it was 'at the start of the transaction'. That is, state updates caused by event firings get processed at the end of the transaction.
changes :: Behavior r a -> Event r aSource
An event that gives the updates for the behavior. It doesn't do any equality comparison as the name might imply.
values :: Behavior r a -> Event r aSource
An event that is guaranteed to fire once when you listen to it, giving
the current value of the behavior, and thereafter behaves like changes,
firing for each update to the behavior's value.
snapshotWith :: (a -> b -> c) -> Event r a -> Behavior r b -> Event r cSource
Sample the behavior at the time of the event firing. Note that the 'current value'
of the behavior that's sampled is the value as at the start of the transaction
before any state changes of the current transaction are applied through holds.
switchE :: Behavior r (Event r a) -> Event r aSource
Unwrap an event inside a behavior to give a time-varying event implementation.
switch :: Behavior r (Behavior r a) -> Reactive r (Behavior r a)Source
Unwrap a behavior inside another behavior to give a time-varying behavior implementation.
execute :: Event r (Reactive r a) -> Event r aSource
Execute the specified Reactive action inside an event.
sample :: Behavior r a -> Reactive r aSource
Obtain the current value of a behavior.
coalesce :: (a -> a -> a) -> Event r a -> Event r aSource
If there's more than one firing in a single transaction, combine them into one using the specified combining function.
If the event firings are ordered, then the first will appear at the left input of the combining function. In most common cases it's best not to make any assumptions about the ordering, and the combining function would ideally be commutative.
once :: Context r => Event r a -> Event r aSource
Throw away all event occurrences except for the first one.
split :: Event r [a] -> Event r aSource
Take each list item and put it into a new transaction of its own.
An example use case of this might be a situation where we are splitting a block of input data into frames. We obviously want each frame to have its own transaction so that state is updated separately each frame.
Arguments
| :: forall r a . Context r | |
| => a | Initial behavior value |
| -> Reactive r (Behavior r a, a -> Reactive r ()) |
Create a new Behavior along with an action to push changes into it.
American spelling.
Arguments
| :: forall r a . Context r | |
| => a | Initial behavior value |
| -> Reactive r (Behavior r a, a -> Reactive r ()) |
Create a new Behavior along with an action to push changes into it.
British spelling.
mergeWith :: Context r => (a -> a -> a) -> Event r a -> Event r a -> Event r aSource
Merge two streams of events of the same type, combining simultaneous event occurrences.
In the case where multiple event occurrences are simultaneous (i.e. all
within the same transaction), they are combined using the same logic as
coalesce.
filterE :: Context r => (a -> Bool) -> Event r a -> Event r aSource
Only keep event occurrences for which the predicate returns true.
snapshot :: Context r => Event r a -> Behavior r b -> Event r bSource
Variant of snapshotWith that throws away the event's value and captures the behavior's.
gate :: Context r => Event r a -> Behavior r Bool -> Event r aSource
Let event occurrences through only when the behavior's value is True. Note that the behavior's value is as it was at the start of the transaction, that is, no state changes from the current transaction are taken into account.
collectE :: Context r => (a -> s -> (b, s)) -> s -> Event r a -> Reactive r (Event r b)Source
Transform an event with a generalized state loop (a mealy machine). The function is passed the input and the old state and returns the new state and output value.
collect :: Context r => (a -> s -> (b, s)) -> s -> Behavior r a -> Reactive r (Behavior r b)Source
Transform a behavior with a generalized state loop (a mealy machine). The function is passed the input and the old state and returns the new state and output value.