| Safe Haskell | None |
|---|
Data.Conduit.Internal
- data Pipe l i o u m r
- newtype ConduitM i o m r = ConduitM {
- unConduitM :: Pipe i i o () m r
- type Source m o = ConduitM () o m ()
- type Producer m o = forall i. ConduitM i o m ()
- type Sink i = ConduitM i Void
- type Consumer i m r = forall o. ConduitM i o m r
- type Conduit i m o = ConduitM i o m ()
- data ResumableSource m o = ResumableSource (Source m o) (m ())
- await :: Pipe l i o u m (Maybe i)
- awaitE :: Pipe l i o u m (Either u i)
- awaitForever :: Monad m => (i -> Pipe l i o r m r') -> Pipe l i o r m r
- yield :: Monad m => o -> Pipe l i o u m ()
- yieldOr :: Monad m => o -> m () -> Pipe l i o u m ()
- leftover :: l -> Pipe l i o u m ()
- bracketP :: MonadResource m => IO a -> (a -> IO ()) -> (a -> Pipe l i o u m r) -> Pipe l i o u m r
- addCleanup :: Monad m => (Bool -> m ()) -> Pipe l i o u m r -> Pipe l i o u m r
- idP :: Monad m => Pipe l a a r m r
- pipe :: Monad m => Pipe l a b r0 m r1 -> Pipe Void b c r1 m r2 -> Pipe l a c r0 m r2
- pipeL :: Monad m => Pipe l a b r0 m r1 -> Pipe b b c r1 m r2 -> Pipe l a c r0 m r2
- connectResume :: Monad m => ResumableSource m o -> Sink o m r -> m (ResumableSource m o, r)
- runPipe :: Monad m => Pipe Void () Void () m r -> m r
- injectLeftovers :: Monad m => Pipe i i o u m r -> Pipe l i o u m r
- (>+>) :: Monad m => Pipe l a b r0 m r1 -> Pipe Void b c r1 m r2 -> Pipe l a c r0 m r2
- (<+<) :: Monad m => Pipe Void b c r1 m r2 -> Pipe l a b r0 m r1 -> Pipe l a c r0 m r2
- sourceToPipe :: Monad m => Source m o -> Pipe l i o u m ()
- sinkToPipe :: Monad m => Sink i m r -> Pipe l i o u m r
- conduitToPipe :: Monad m => Conduit i m o -> Pipe l i o u m ()
- toProducer :: Monad m => Source m a -> Producer m a
- toConsumer :: Monad m => Sink a m b -> Consumer a m b
- transPipe :: Monad m => (forall a. m a -> n a) -> Pipe l i o u m r -> Pipe l i o u n r
- mapOutput :: Monad m => (o1 -> o2) -> Pipe l i o1 u m r -> Pipe l i o2 u m r
- mapOutputMaybe :: Monad m => (o1 -> Maybe o2) -> Pipe l i o1 u m r -> Pipe l i o2 u m r
- mapInput :: Monad m => (i1 -> i2) -> (l2 -> Maybe l1) -> Pipe l2 i2 o u m r -> Pipe l1 i1 o u m r
- sourceList :: Monad m => [a] -> Pipe l i a u m ()
- withUpstream :: Monad m => Pipe l i o u m r -> Pipe l i o u m (u, r)
- unwrapResumable :: MonadIO m => ResumableSource m o -> m (Source m o, m ())
Types
The underlying datatype for all the types in this package. In has six type parameters:
- l is the type of values that may be left over from this
Pipe. APipewith no leftovers would useVoidhere, and one with leftovers would use the same type as the i parameter. Leftovers are automatically provided to the nextPipein the monadic chain. - i is the type of values for this
Pipe's input stream. - o is the type of values for this
Pipe's output stream. - u is the result type from the upstream
Pipe. - m is the underlying monad.
- r is the result type.
A basic intuition is that every Pipe produces a stream of output values
(o), and eventually indicates that this stream is terminated by sending a
result (r). On the receiving end of a Pipe, these become the i and u
parameters.
Since 0.5.0
Constructors
| HaveOutput (Pipe l i o u m r) (m ()) o | Provide new output to be sent downstream. This constructor has three
fields: the next |
| NeedInput (i -> Pipe l i o u m r) (u -> Pipe l i o u m r) | Request more input from upstream. The first field takes a new input
value and provides a new |
| Done r | Processing with this |
| PipeM (m (Pipe l i o u m r)) | Require running of a monadic action to get the next |
| Leftover (Pipe l i o u m r) l | Return leftover input, which should be provided to future operations. |
Instances
| MonadRWS r w s m => MonadRWS r w s (Pipe l i o u m) | |
| MonadBase base m => MonadBase base (Pipe l i o u m) | |
| MonadError e m => MonadError e (Pipe l i o u m) | |
| MonadReader r m => MonadReader r (Pipe l i o u m) | |
| MonadWriter w m => MonadWriter w (Pipe l i o u m) | |
| MonadState s m => MonadState s (Pipe l i o u m) | |
| MFunctor (Pipe l i o u) | Since 1.0.4 |
| MonadTrans (Pipe l i o u) | |
| Monad m => Monad (Pipe l i o u m) | |
| Monad m => Functor (Pipe l i o u m) | |
| Monad m => Applicative (Pipe l i o u m) | |
| MonadActive m => MonadActive (Pipe l i o u m) | |
| MonadResource m => MonadResource (Pipe l i o u m) | |
| MonadThrow m => MonadThrow (Pipe l i o u m) | |
| MonadIO m => MonadIO (Pipe l i o u m) | |
| Monad m => Monoid (Pipe l i o u m ()) |
newtype ConduitM i o m r Source
Core datatype of the conduit package. This type represents a general
component which can consume a stream of input values i, produce a stream
of output values o, perform actions in the m monad, and produce a final
result r. The type synonyms provided here are simply wrappers around this
type.
Since 1.0.0
Constructors
| ConduitM | |
Fields
| |
Instances
| MonadRWS r w s m => MonadRWS r w s (ConduitM i o m) | |
| MonadBase base m => MonadBase base (ConduitM i o m) | |
| MonadError e m => MonadError e (ConduitM i o m) | |
| MonadReader r m => MonadReader r (ConduitM i o m) | |
| MonadWriter w m => MonadWriter w (ConduitM i o m) | |
| MonadState s m => MonadState s (ConduitM i o m) | |
| MFunctor (ConduitM i o) | |
| MonadTrans (ConduitM i o) | |
| Monad m => Monad (ConduitM i o m) | |
| Monad m => Functor (ConduitM i o m) | |
| Monad m => Applicative (ConduitM i o m) | |
| MonadActive m => MonadActive (ConduitM i o m) | |
| MonadResource m => MonadResource (ConduitM i o m) | |
| MonadThrow m => MonadThrow (ConduitM i o m) | |
| MonadIO m => MonadIO (ConduitM i o m) | |
| Monad m => Monoid (ConduitM i o m ()) |
type Source m o = ConduitM () o m ()Source
Provides a stream of output values, without consuming any input or producing a final result.
Since 0.5.0
type Producer m o = forall i. ConduitM i o m ()Source
A component which produces a stream of output values, regardless of the
input stream. A Producer is a generalization of a Source, and can be
used as either a Source or a Conduit.
Since 1.0.0
type Sink i = ConduitM i VoidSource
Consumes a stream of input values and produces a final result, without producing any output.
type Sink i m r = ConduitM i Void m r
Since 0.5.0
type Consumer i m r = forall o. ConduitM i o m rSource
A component which consumes a stream of input values and produces a final
result, regardless of the output stream. A Consumer is a generalization of
a Sink, and can be used as either a Sink or a Conduit.
Since 1.0.0
type Conduit i m o = ConduitM i o m ()Source
Consumes a stream of input values and produces a stream of output values, without producing a final result.
Since 0.5.0
data ResumableSource m o Source
A Source which has been started, but has not yet completed.
This type contains both the current state of the Source, and the finalizer
to be run to close it.
Since 0.5.0
Constructors
| ResumableSource (Source m o) (m ()) |
Primitives
awaitE :: Pipe l i o u m (Either u i)Source
This is similar to await, but will return the upstream result value as
Left if available.
Since 0.5.0
awaitForever :: Monad m => (i -> Pipe l i o r m r') -> Pipe l i o r m rSource
Wait for input forever, calling the given inner Pipe for each piece of
new input. Returns the upstream result type.
Since 0.5.0
Send a single output value downstream. If the downstream Pipe
terminates, this Pipe will terminate as well.
Since 0.5.0
Similar to yield, but additionally takes a finalizer to be run if the
downstream Pipe terminates.
Since 0.5.0
leftover :: l -> Pipe l i o u m ()Source
Provide a single piece of leftover input to be consumed by the next pipe in the current monadic binding.
Note: it is highly encouraged to only return leftover values from input already consumed from upstream.
Since 0.5.0
Finalization
bracketP :: MonadResource m => IO a -> (a -> IO ()) -> (a -> Pipe l i o u m r) -> Pipe l i o u m rSource
Perform some allocation and run an inner Pipe. Two guarantees are given
about resource finalization:
- It will be prompt. The finalization will be run as early as possible.
- It is exception safe. Due to usage of
resourcet, the finalization will be run in the event of any exceptions.
Since 0.5.0
Arguments
| :: Monad m | |
| => (Bool -> m ()) |
|
| -> Pipe l i o u m r | |
| -> Pipe l i o u m r |
Add some code to be run when the given Pipe cleans up.
Since 0.4.1
Composition
pipe :: Monad m => Pipe l a b r0 m r1 -> Pipe Void b c r1 m r2 -> Pipe l a c r0 m r2Source
Compose a left and right pipe together into a complete pipe. The left pipe will be automatically closed when the right pipe finishes.
Since 0.5.0
pipeL :: Monad m => Pipe l a b r0 m r1 -> Pipe b b c r1 m r2 -> Pipe l a c r0 m r2Source
Same as pipe, but automatically applies injectLeftovers to the right Pipe.
Since 0.5.0
connectResume :: Monad m => ResumableSource m o -> Sink o m r -> m (ResumableSource m o, r)Source
Connect a Source to a Sink until the latter closes. Returns both the
most recent state of the Source and the result of the Sink.
We use a ResumableSource to keep track of the most recent finalizer
provided by the Source.
Since 0.5.0
runPipe :: Monad m => Pipe Void () Void () m r -> m rSource
Run a pipeline until processing completes.
Since 0.5.0
injectLeftovers :: Monad m => Pipe i i o u m r -> Pipe l i o u m rSource
Transforms a Pipe that provides leftovers to one which does not,
allowing it to be composed.
This function will provide any leftover values within this Pipe to any
calls to await. If there are more leftover values than are demanded, the
remainder are discarded.
Since 0.5.0
(>+>) :: Monad m => Pipe l a b r0 m r1 -> Pipe Void b c r1 m r2 -> Pipe l a c r0 m r2Source
Fuse together two Pipes, connecting the output from the left to the
input of the right.
Notice that the leftover parameter for the Pipes must be Void. This
ensures that there is no accidental data loss of leftovers during fusion. If
you have a Pipe with leftovers, you must first call injectLeftovers.
Since 0.5.0
(<+<) :: Monad m => Pipe Void b c r1 m r2 -> Pipe l a b r0 m r1 -> Pipe l a c r0 m r2Source
Same as >+>, but reverse the order of the arguments.
Since 0.5.0
Generalizing
sourceToPipe :: Monad m => Source m o -> Pipe l i o u m ()Source
sinkToPipe :: Monad m => Sink i m r -> Pipe l i o u m rSource
conduitToPipe :: Monad m => Conduit i m o -> Pipe l i o u m ()Source
toProducer :: Monad m => Source m a -> Producer m aSource
toConsumer :: Monad m => Sink a m b -> Consumer a m bSource
Utilities
transPipe :: Monad m => (forall a. m a -> n a) -> Pipe l i o u m r -> Pipe l i o u n rSource
Transform the monad that a Pipe lives in.
Note that the monad transforming function will be run multiple times, resulting in unintuitive behavior in some cases. For a fuller treatment, please see:
https://github.com/snoyberg/conduit/wiki/Dealing-with-monad-transformers
This function is just a synonym for hoist.
Since 0.4.0
mapOutputMaybe :: Monad m => (o1 -> Maybe o2) -> Pipe l i o1 u m r -> Pipe l i o2 u m rSource
Same as mapOutput, but use a function that returns Maybe values.
Since 0.5.0
Arguments
| :: Monad m | |
| => (i1 -> i2) | map initial input to new input |
| -> (l2 -> Maybe l1) | map new leftovers to initial leftovers |
| -> Pipe l2 i2 o u m r | |
| -> Pipe l1 i1 o u m r |
Apply a function to all the input values of a Pipe.
Since 0.5.0
sourceList :: Monad m => [a] -> Pipe l i a u m ()Source
Convert a list into a source.
Since 0.3.0
withUpstream :: Monad m => Pipe l i o u m r -> Pipe l i o u m (u, r)Source
Returns a tuple of the upstream and downstream results. Note that this will force consumption of the entire input stream.
Since 0.5.0
unwrapResumable :: MonadIO m => ResumableSource m o -> m (Source m o, m ())Source
Unwraps a ResumableSource into a Source and a finalizer.
A ResumableSource represents a Source which has already been run, and
therefore has a finalizer registered. As a result, if we want to turn it
into a regular Source, we need to ensure that the finalizer will be run
appropriately. By appropriately, I mean:
- If a new finalizer is registered, the old one should not be called.
- If the old one is called, it should not be called again.
This function returns both a Source and a finalizer which ensures that the
above two conditions hold. Once you call that finalizer, the Source is
invalidated and cannot be used.
Since 0.5.2