Packages

  • package root
    Definition Classes
    root
  • package h8io
    Definition Classes
    root
  • package stages
    Definition Classes
    h8io
  • package base

    Type aliases used throughout the lib module for describing stage transformations.

    Type aliases used throughout the lib module for describing stage transformations.

    // A decorator is a stage itself: it wraps a Stage[I, O, E] and is one:
val myDecorator: Decorator[String, Int, Nothing] = CompleteIfNone(stage)

// A decoration is the function building it; an alteration is the same with the types free to change:
val myDecoration: Decoration[String, Int, Nothing] = CompleteIfNone(_)
val myAlteration: Alteration[Stage[String, Int, Nothing], Stage[String, Option[Int], Nothing]] = Lift(_)
    Definition Classes
    stages
  • package cats
    Definition Classes
    stages
  • package cycles
    Definition Classes
    stages
  • package operators
    Definition Classes
    stages
  • package projections
    Definition Classes
    stages
  • package std
    Definition Classes
    stages
  • Evolution
  • Stage
  • Status
  • Yield

trait Evolution[-I, +O, +E] extends AnyRef

The continuation of a Stage: which stage handles the next input, chosen by the Status of the run that just finished. This is what makes a pipeline able to change as it runs — every Yield carries one.

An Evolution is also the exclusive owner of cleanup for the stage that produced it: see dispose.

The status to select on is the one carried alongside the evolution in the same yield, which is why callers normally go through Yield.evolve rather than dispatching on a status themselves. In a composed pipeline that status is the combined one of the whole run, never a single stage's own.

I

the input type of the stages returned (contravariant)

O

their output type (covariant)

E

the error type (covariant)

Linear Supertypes
AnyRef, Any
Known Subclasses
Evolution, ConstEvolution, Fn, FruitfulStaticStage, LeftProjection, Projection, RightProjection, SAMStage, Stagnation, StaticStage, Left, Right, Invalid, Valid, Left, Right, Left, Right, Unlift, Coalesce, Complete, Const, Countdown, DeadEnd, DeadEnd, GlobalSoftDeadline, Identity, Swap
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  1. Evolution
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Abstract Value Members

  1. abstract def dispose(): Unit

    Releases everything held by the Stage that produced this evolution.

    Releases everything held by the Stage that produced this evolution. That stage is permanently unusable afterwards — neither applied nor skipped again — and this is the only place its resources are released.

    Whoever terminates a pipeline is responsible for disposing the evolution of the final Yield, so that the continuation is released at once instead of being carried around. The reference terminal driver is the execute extension method of h8io.stages.base in the lib module.

    dispose() stays valid after evolve has been called on the same instance, and must then release everything still alive, including whatever building the continuation acquired. evolve hands over no ownership: this evolution remains the cleanup point for its lineage until the continuation has run and produced an evolution of its own, which takes the role over from that moment.

    Exceptions are not part of this contract: a stage whose apply throws produces no yield and therefore no evolution, so there is nothing to dispose — it must clean up after itself (see the Lifecycle section in Stage).

    A no-op is a fine implementation for a stage holding nothing external.

  2. abstract def evolve(status: Status[_]): Stage[I, O, E]

    The next stage, for the given status.

    The next stage, for the given status.

    May release what belongs to this generation alone — anything the returned stage and its own evolution will not reuse.

    evolve and dispose are not mutually exclusive. Usually only one of them is called on an instance: a terminal driver disposes, a continuing pipeline evolves and drops the previous evolution. But a caller may do both, and operators owning their inner stage (Loop, Repeat and the rest of h8io.stages.cycles in the lib module) do exactly that — they evolve eagerly and keep the inner dispose as the cleanup handle of the generation they just built.

Concrete Value Members

  1. final def !=(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  2. final def ##(): Int
    Definition Classes
    AnyRef → Any
  3. final def ==(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  4. final def asInstanceOf[T0]: T0
    Definition Classes
    Any
  5. def clone(): AnyRef
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( ... ) @native() @IntrinsicCandidate()
  6. final def compose[_O, _E >: E](that: Evolution[O, _O, _E]): Evolution[I, _O, _E]

    Composes this evolution with the one downstream of it, so that for every status

    Composes this evolution with the one downstream of it, so that for every status

    composed(s) == self(s) ~> that(s)

    This is how Yield composition carries both continuations of a pipeline forward; application code rarely calls it directly.

    Annotations
    @inline()
  7. final def eq(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  8. def equals(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  9. final def getClass(): Class[_]
    Definition Classes
    AnyRef → Any
    Annotations
    @native() @IntrinsicCandidate()
  10. def hashCode(): Int
    Definition Classes
    AnyRef → Any
    Annotations
    @native() @IntrinsicCandidate()
  11. final def isInstanceOf[T0]: Boolean
    Definition Classes
    Any
  12. final def map[_I, _O, _E](f: (Stage[I, O, E]) ⇒ Stage[_I, _O, _E]): Evolution[_I, _O, _E]

    Applies f to every stage this evolution would return, leaving disposal delegated to it unchanged.

    Applies f to every stage this evolution would return, leaving disposal delegated to it unchanged.

    The way an operator keeps its wrapping in place across generations: the continuation comes back wrapped the same way the current stage is.

    Annotations
    @inline()
  13. final def ne(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  14. final def notify(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native() @IntrinsicCandidate()
  15. final def notifyAll(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native() @IntrinsicCandidate()
  16. final def synchronized[T0](arg0: ⇒ T0): T0
    Definition Classes
    AnyRef
  17. def toString(): String
    Definition Classes
    AnyRef → Any
  18. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  19. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... ) @native()
  20. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )

Deprecated Value Members

  1. def finalize(): Unit
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( classOf[java.lang.Throwable] ) @Deprecated
    Deprecated

Inherited from AnyRef

Inherited from Any

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