Pull

Provides syntax for pure pulls based on cats.Id.

An abstraction for writing Pull computations that can timeout while reading from a Stream.

A Pull.Timed is not created or intepreted directly, but by calling Stream.ToPull.timed.

yourStream.pull.timed(tp => ...).stream

The argument to timed is a Pull.Timed[F, O] => Pull[F, O2, R] function, which describes the pulling logic and is often recursive, with shape:

def go(timedPull: Pull.Timed[F, A]): Pull[F, B, Unit] =
 timedPull.uncons.flatMap {
   case Some((Right(chunk), next)) => doSomething >> go(next)
   case Some((Left(_), next)) => doSomethingElse >> go(next)
   case None => Pull.done
 }

Where doSomething and doSomethingElse are Pull computations such as Pull.output, in addition to Pull.Timed.timeout.

See below for detailed descriptions of timeout and uncons, and look at the Stream.ToPull.timed scaladoc for an example of usage.

Like eval but if the effectful value fails, the exception is returned in a Left instead of failing the pull.

Creates a pull that evaluates the supplied effect fr, emits no outputs, and terminates with the result of the effect. If the fr effect fails with an error, the new pull fails with that error.

Extends the scope of the currently open resources to the specified stream, preventing them from being finalized until after s completes execution, even if the returned pull is converted to a stream, compiled, and evaluated before s is compiled and evaluated.

Lifts an Either[Throwable, A] to an effectful Pull[F, A, Unit].

Repeatedly uses the output of the pull as input for the next step of the pull. Halts when a step terminates with None or Pull.raiseError.

Intantiates with a state. Repeatedly uses the left value of the result of the pull as input for the next step. The Pull terminates when a step terminates with Right or Pull.raiseError.

Creates a pull that emits the elements of the given chunk. The new pull performs no effects and terminates successfully with a unit result.

Lifts the given output value O into a pull that performs no effects, emits that single output in a singleton chunk, and always terminates successfully with a unit result.

Note: using singleton chunks is not efficient. If possible, use the chunk-based output method instead.

Lifts the given optional value O into a pull that performs no effects, emits the content of that option, and always terminates successfully with a unit result.

Creates an pull that performs no effects, emits no outputs, and terminates successfully with the supplied value as its result.

Lifts a throwable error into an atomic pull that emits no outputs and fails with the given error, without any result.

The F type must be explicitly provided (e.g., via raiseError[IO] or raiseError[Fallible]).

Creates a pull that waits for the duration d

Returns a pull that evaluates the supplied by-name each time the pull is used, allowing use of a mutable value in pull computations.

A pull that performs no effects, emits no outputs, and always terminates successfully with a unit result.

Provides syntax for pure pulls based on cats.Id.

FunctionK instance for F ~> Pull[F, Nothing, *]

Sync instance for Pull.