final class Scan[S, -I, +O] extends AnyRef
A stateful transformation of the elements of a stream.
A scan is primarily represented as a function (S, I) => (S, Chunk[O]).
Scans also have an initial state value of type S and the ability to emit
elements upon completion via a function S => Chunk[O].
A scan is built up incrementally via various combinators and then converted to
a pipe via .toPipe. For example, s.through(Scan.lift(identity).toPipe) == s.
A scan is much less powerful than a pull. Scans cannot evaluate effects or terminate
early. These limitations allow combinators that are not possible on pulls though.
For example, the first method converts a Scan[S, I, O] to a Scan[S, (I, A), (O, A)].
Critically, this method relies on the ability to feed a single I to the original scan
and collect the resulting O values, pairing each O with the A that was paired with I.
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- Scan.scala
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- def andThen[S2, O2](that: Scan[S2, O, O2]): Scan[(S, S2), I, O2]
Composes the supplied scan with this scan.
Composes the supplied scan with this scan.
The resulting scan maintains the state of each of the input scans independently.
- final def asInstanceOf[T0]: T0
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- def choice[S2, I2, O2 >: O](that: Scan[S2, I2, O2]): Scan[(S, S2), Either[I, I2], O2]
Combines this scan with the supplied scan such that elements on the left are fed through this scan while elements on the right are fed through the suppplied scan.
Combines this scan with the supplied scan such that elements on the left are fed through this scan while elements on the right are fed through the suppplied scan. The outputs are joined together.
- def choose[S2, I2, O2](t: Scan[S2, I2, O2]): Scan[(S, S2), Either[I, I2], Either[O, O2]]
Like choice but the output elements are kept separate.
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- @throws(classOf[java.lang.CloneNotSupportedException]) @IntrinsicCandidate() @native()
- def contramap[I2](f: (I2) => I): Scan[S, I2, O]
Returns a new scan which transforms input values using the supplied function.
- def dimap[I2, O2](g: (I2) => I)(f: (O) => O2): Scan[S, I2, O2]
- final def eq(arg0: AnyRef): Boolean
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- def equals(arg0: AnyRef): Boolean
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- def first[A]: Scan[S, (I, A), (O, A)]
Returns a scan that inputs/outputs pairs of elements, with
IandOin the first element of the pair. - final def getClass(): Class[_ <: AnyRef]
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- def hashCode(): Int
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- def imapState[S2](g: (S) => S2)(f: (S2) => S): Scan[S2, I, O]
Transforms the state type.
- val initial: S
- final def isInstanceOf[T0]: Boolean
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- def left[A]: Scan[S, Either[I, A], Either[O, A]]
Returns a scan that wraps the inputs/outputs with
Either.Returns a scan that wraps the inputs/outputs with
Either. Elements on the left pass through the original scan while elements on the right pass through directly. - def lens[I2, O2](get: (I2) => I, set: (I2, O) => O2): Scan[S, I2, O2]
Returns a new scan with transformed input and output types.
Returns a new scan with transformed input and output types.
Upon receiving an
I2,getis invoked and the result is fed to the original scan. For each output value,setis invoked with the originalI2input and the computedO, yielding a new output of typeO2. - def map[O2](f: (O) => O2): Scan[S, I, O2]
Returns a new scan which transforms output values using the supplied function.
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- final def notify(): Unit
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- def onComplete(s: S): Chunk[O]
Completion function.
- def right[A]: Scan[S, Either[A, I], Either[A, O]]
Returns a scan that wraps the inputs/outputs with
Either.Returns a scan that wraps the inputs/outputs with
Either. Elements on the right pass through the original scan while elements on the left pass through directly. - def second[A]: Scan[S, (A, I), (A, O)]
Returns a scan that inputs/outputs pairs of elements, with
IandOin the second element of the pair. - def semilens[I2, O2](extract: (I2) => Either[O2, I], inject: (I2, O) => O2): Scan[S, I2, O2]
Like lens but some elements are passed to the output (skipping the original scan) while other elements are lensed through the original scan.
- def semipass[I2, O2 >: O](extract: (I2) => Either[O2, I]): Scan[S, I2, O2]
Like semilens but the elements of the original scan are output directly.
- def step(i: I): (Scan[S, I, O], Chunk[O])
Steps this scan by a single input, returning a new scan and the output elements computed from the input.
- final def synchronized[T0](arg0: => T0): T0
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- def toPipe[F[_]]: (Stream[F, I]) => Stream[F, O]
Converts this scan to a pipe.
- def toString(): String
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- def transform(s: S, i: I): (S, Chunk[O])
Transformation function.
- def transformAccumulate(s: S, c: Chunk[I]): (S, Chunk[O])
Chunk form of transform.
- final def wait(arg0: Long, arg1: Int): Unit
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- final def wait(arg0: Long): Unit
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