Bluefin.Stream

Documentation

Stream allows you to yield values during the execution of a Bluefin operation. It provides similar functionality to Python's yield. The handler of the Stream will either handle each element as soon as it is yielded (for example forEach) or gather all yielded elements int o a list (for example yieldToList).

Handle

type Stream a = Coroutine a ()

A handle to a stream that yields values of type a. It is implemented as a handle to a coroutine that expects values of type () and then yields values of type a.

Handlers

forEach

Arguments

:: forall a b (es :: Effects) r. (forall (e1 :: Effects). Coroutine a b e1 -> Eff (e1 :& es) r)

-> (a -> Eff es b)

Apply this effectful function for each element of the coroutine

-> Eff es r

>>> 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], ())

yieldToList

Arguments

:: forall a (es :: Effects) r. (forall (e1 :: Effects). Stream a e1 -> Eff (e1 :& es) r)

-> Eff es ([a], r)

Yielded elements and final result

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

yieldToReverseList

Arguments

:: forall a (es :: Effects) r. (forall (e :: Effects). Stream a e -> Eff (e :& es) r)

-> Eff es ([a], r)

Yielded elements in reverse order, and final result

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], ())

enumerate

Arguments

:: forall (e2 :: Effects) (es :: Effects) a r. e2 :> es

=> (forall (e1 :: Effects). Stream a e1 -> Eff (e1 :& es) r)

͘

-> Stream (Int, a) e2

-> Eff es r

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")], ())

enumerateFrom

Arguments

:: forall (e2 :: Effects) (es :: Effects) a r. e2 :> es

=> Int

Initial value

-> (forall (e1 :: Effects). Stream a e1 -> Eff (e1 :& es) r)

-> Stream (Int, a) e2

-> Eff es r

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

>>> runPureEff $ yieldToList $ enumerateFrom1 (inFoldable ["A", "B", "C"])
([(1, "A"), (2, "B"), (3, "C")], ())

mapMaybe

Arguments

:: forall (e2 :: Effects) (es :: Effects) a b r. e2 :> es

=> (a -> Maybe b)

Yield from the output stream all of the elemnts of the input stream for which this function returns Just

-> (forall (e1 :: Effects). Stream a e1 -> Eff (e1 :& es) r)

Input stream

-> Stream b e2

-> Eff es r

catMaybes

Arguments

:: forall (e2 :: Effects) (es :: Effects) a r. e2 :> es

=> (forall (e1 :: Effects). Stream (Maybe a) e1 -> Eff (e1 :& es) r)

Input stream

-> Stream a e2

-> Eff es r

Remove Nothing elements from a stream.

Effectful operations

yield

Arguments

:: forall (e1 :: Effects) (es :: Effects) a. e1 :> es

=> Stream a e1

-> a

Yield this value from the stream

-> Eff es ()

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

inFoldable

Arguments

:: forall t (e1 :: Effects) (es :: Effects) a. (Foldable t, e1 :> es)

=> t a

Yield all these values from the stream

-> Stream a e1

-> Eff es ()

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