Capability to yield values of type a. It is implemented as a Request capability that can yield values of type a and then await values of type ().

Apply an effectful function to each element yielded to the stream.

>>> runPureEff $ yieldToList $ \y -> do
      forEach (inFoldable [0 .. 3]) $ \i -> do
        yield y i
        yield y (i * 10)
([0, 0, 1, 10, 2, 20, 3, 30], ())

Gather all yielded elements into a list.

>>> runPureEff $ yieldToList $ \y -> do
      yield y 1
      yield y 2
      yield y 100
([1,2,100], ())

This is more efficient than yieldToList because it gathers the elements into a stack in reverse order. yieldToList then reverses that stack.

>>> runPureEff $ yieldToReverseList $ \y -> do
      yield y 1
      yield y 2
      yield y 100
([100,2,1], ())

>>> runPureEff $ withYieldToList $ \y -> do
  yield y 1
  yield y 2
  yield y 100
  pure length
3

Ignore all yielded elements.

>>> runPureEff $ ignoreYield $ \y -> do
     for_ [0 .. 4] $ \i -> do
       yield y i
       yield y (i * 10)

     pure 42
42

Pair each element in the stream with an increasing index, starting from 0.

>>> runPureEff $ yieldToList $ enumerate (inFoldable ["A", "B", "C"])
([(0, "A"), (1, "B"), (2, "C")], ())

Pair each element in the stream with an increasing index, starting from an inital value.

>>> runPureEff $ yieldToList $ enumerateFrom 1 (inFoldable ["A", "B", "C"])
([(1, "A"), (2, "B"), (3, "C")], ())

Remove Nothing elements from a stream.

awaitYield is connectRequests specialized to Await and Yield, which is the most common case.

Yield an element to the stream.

>>> runPureEff $ yieldToList $ \y -> do
      yield y 1
      yield y 2
      yield y 100
([1,2,100], ())

>>> runPureEff $ yieldToList $ inFoldable [1, 2, 100]
([1, 2, 100], ())

runPureEff $ yieldToList $ yOut -> do
  consumeStream
    (\c -> takeAwait 6 c yOut)
    (\yIn -> cycleToYield [1..3] yIn)
([1,2,3,1,2,3],())

runPureEff $ yieldToList $ yOut -> do
  awaitYield
    (\c -> takeAwait 4 c yOut)
    (\yIn -> inFoldable [1..10] yIn)
([1,2,3,4],())