Type Members

1.  type /=[M[_], R] = MemberInOut[M, R]
2.  type <=[M[_], R] = Member[M, R]
3.  case class Arrs[R, A, B](functions: Vector[(Any) ⇒ Eff[R, Any]]) extends (A) ⇒ Eff[R, B] with Product with Serializable

   Sequence of monadic functions from A to B: A => Eff[B]

   Sequence of monadic functions from A to B: A => Eff[B]

   Internally it is represented as a Vector of functions:

   A => Eff[R, X1]; X1 => Eff[R, X2]; X2 => Eff[R, X3]; ...; X3 => Eff[R, B]

4.  trait Augment[T[_], O[_]] extends AnyRef
5.  trait Cache extends AnyRef

   This cache is used to memoize values for the Memoized effect

6.  case class CollectedUnions[M[_], R, U](effects: List[M[Any]], otherEffects: List[Union[U, Any]], indices: List[Int], otherIndices: List[Int]) extends Product with Serializable

   Collection of effects of a given type from a Unions objects

7.  case class ConcurrentHashMapCache(map: ConcurrentHashMap[AnyRef, Evaluated[Any]] = ...) extends Cache with Product with Serializable
8.  class ConcurrentWeakIdentityHashMap[K, V] extends ConcurrentMap[K, V]

9.  case class ConcurrentWeakIdentityHashMapCache(map: ConcurrentWeakIdentityHashMap[AnyRef, Evaluated[Any]] = ...) extends Cache with Product with Serializable
10.  trait DisjunctionCreation extends AnyRef
11.  trait DisjunctionEffect extends DisjunctionCreation with DisjunctionInterpretation

    Effect for computation which can fail

12.  trait DisjunctionInterpretation extends AnyRef
13.  sealed trait Eff[R, A] extends AnyRef

    Effects of type R, returning a value of type A

    Effects of type R, returning a value of type A

    It is implemented as a "Free-er" monad with extensible effects:

    • the "pure" case is a pure value of type A
    • the "impure" case is:
      • a disjoint union of possible effects
      • a continuation of type X => Eff[R, A] indicating what to do if the current effect is of type M[X] this type is represented by the Arrs type
    • the "impure applicative" case is:
      • list of disjoint unions of possible effects
      • a function to apply to the values resulting from those effects

    The monad implementation for this type is really simple:

    • point is Pure
    • bind simply appends the binding function to the Arrs continuation

    Important:

    The list of continuations is NOT implemented as a type sequence but simply as a Vector[Any => Eff[R, Any]]

    This means that various .asInstanceOf are present in the implementation and could lead to burns and severe harm. Use with caution!

    Similarly the list of effects in the applicative case is untyped and interpreters for those effects are supposed to create a list of values to feed the mapping function. If an interpreter doesn't create a list of values of the right size and with the right types, there will be a runtime exception.

    The Pure, Impure and ImpureAp cases also incorporate a "last" action returning no value but just used for side-effects (shutting down an execution context for example). This action is meant to be executed at the end of all computations, regardless of the number of flatMaps added on the Eff value.

    Since this last action will be executed, its value never collected so if it throws an exception it is possible to print it by defining the eff.debuglast system property (-Deff.debuglast=true)

    See also

    http://okmij.org/ftp/Haskell/extensible/more.pdf

14.  trait EffCreation extends AnyRef
15.  trait EffImplicits extends AnyRef
16.  trait EffInterpretation extends AnyRef
17.  sealed trait Effect[F[_]] extends AnyRef

    one effect, basically a type constructor

18.  trait ErrorCreation[F] extends ErrorTypes[F]
19.  trait ErrorEffect[F] extends ErrorCreation[F] with ErrorInterpretation[F]

    Effect for computation which can fail and return a Throwable, or just stop with a failure

    Effect for computation which can fail and return a Throwable, or just stop with a failure

    This effect is a mix of Eval and Either in the sense that every computation passed to this effect (with the ok method) is considered "impure" or "faulty" by default.

    The type F is used to represent the failure type.

20.  trait ErrorInterpretation[F] extends ErrorCreation[F]
21.  trait ErrorTypes[F] extends AnyRef
22.  trait EvalCreation extends EvalTypes
23.  trait EvalEffect extends EvalTypes with EvalCreation with EvalInterpretation

    Effect for delayed computations

    Effect for delayed computations

    uses scalaz.Need as a supporting data structure

24.  trait EvalInterpretation extends EvalTypes
25.  trait EvalTypes extends AnyRef
26.  case class Evaluate[F, A](run: Either[Either[Throwable, F], Name[A]]) extends Product with Serializable
27.  case class EvaluateValue[A](a: Name[A]) extends Safe[A] with Product with Serializable
28.  trait Evaluated[+T] extends AnyRef
29.  case class FailedFinalizer(t: Throwable) extends Safe[Unit] with Product with Serializable
30.  case class FailedValue[A](t: Throwable) extends Safe[A] with Product with Serializable
31.  trait FutureCreation extends FutureTypes
32.  trait FutureEffect extends FutureCreation with FutureInterpretation
33.  trait FutureInterpretation extends FutureTypes
34.  trait FutureTypes extends AnyRef
35.  sealed trait Fx extends AnyRef

    Base type for a tree of effect types

36.  final case class Fx1[F[_]](e: Effect[F]) extends Fx with Product with Serializable
37.  final case class Fx2[L[_], R[_]](left: Effect[L], right: Effect[R]) extends Fx with Product with Serializable
38.  final case class Fx3[L[_], M[_], R[_]](left: Effect[L], middle: Effect[M], right: Effect[R]) extends Fx with Product with Serializable
39.  final case class FxAppend[L, R](left: L, right: R) extends Fx with Product with Serializable

    Append a tree of effects to another one

40.  case class Impure[R, X, A](union: Union[R, X], continuation: Arrs[R, X, A], last: Last[R] = Last.none[R]) extends Eff[R, A] with Product with Serializable

    Impure is an effect (encoded as one possibility among other effects, a Union) and a continuation providing the next Eff value.

    Impure is an effect (encoded as one possibility among other effects, a Union) and a continuation providing the next Eff value.

    This essentially models a flatMap operation with the current effect and the monadic function to apply to a value once the effect is interpreted

    One effect can always be executed last, just for side-effects

41.  case class ImpureAp[R, X, A](unions: Unions[R, X], continuation: Arrs[R, List[Any], A], last: Last[R] = Last.none[R]) extends Eff[R, A] with Product with Serializable

    ImpureAp is a list of independent effects and a pure function creating a value with all the resulting values once all effects have been interpreted.

    ImpureAp is a list of independent effects and a pure function creating a value with all the resulting values once all effects have been interpreted.

    This essentially models a sequence + map operation but it is important to understand that the list of Union objects can represent different effects and be like: List[Option[Int], Future[String], Option[Int]].

    Interpreting such an Eff value for a given effect (say Option) consists in:

    • grouping all the Option values,
    • sequencing them
    • pass them to a continuation which will apply the 'map' functions when the other effects (Future in the example above) will have been interpreted

    VERY IMPORTANT:

    • this object is highly unsafe
    • the size of the list argument to 'map' must always be equal to the number of unions in the Unions object
    • the types of the elements in the list argument to 'map' must be the exact types of each effect in unions.unions
42.  trait Interpret extends AnyRef

    Support methods to create interpreters (or "effect handlers") for a given effect M and a value Eff[R, A] when M is a member of R.

    Support methods to create interpreters (or "effect handlers") for a given effect M and a value Eff[R, A] when M is a member of R.

    Those methods guarantee a stack-safe behaviour when running on a large list of effects (in list.traverse(f) for example).

    There are different types of supported interpreters:

    1. "interpret" + Recurse

    This interpreter is used to handle effects which either return a value X from M[X] or stops with Eff[R, B] See an example of such an interpreter in Eval where we just evaluate a computation X for each Eval[X].

    2. "interpretState" + StateRecurse

    This interpreter is used to handle effects which either return a value X from M[X] or stops with Eff[R, B]

    3. "interpretLoop" + Loop

    The most generic kind of interpreter where we can even recurse in the case of Pure(a) (See ListEffect for such a use)

    4. "intercept / interceptState / interceptLoop" methods are similar but they transform an effect to other effects in the same stack without removing it from the stack

    5. "transform" to swap an effect T of a stack to another effect, using a Natural Transformation

    6. "translate" to interpret one effect of a stack into other effects of the same stack using a Natural Transformation this is a specialized version of interpret + Recurse

    7. "interpretUnsafe + SideEffect" when you have a side effecting function M[X] => X

43.  trait IntoPoly[R, U] extends AnyRef

    Typeclass proving that it is possible to send a tree of effects R into another tree of effects U

    Typeclass proving that it is possible to send a tree of effects R into another tree of effects U

    for example

    send[Option1, Fx.fx3[Option1, Option2, Option3], Int](Option1(1)). into[Fx.fx5[Option1, Option2, Option3, Option4, Option5]]

    should work because all the effects of the first stack are present in the second

    Note: some implicit definitions are probably missing in some cases

44.  trait IntoPolyLower1 extends IntoPolyLower2
45.  trait IntoPolyLower2 extends IntoPolyLower3
46.  trait IntoPolyLower3 extends IntoPolyLower4
47.  trait IntoPolyLower4 extends IntoPolyLower5
48.  trait IntoPolyLower5 extends AnyRef
49.  case class Last[R](value: Option[Name[Eff[R, Unit]]]) extends Product with Serializable

    Encapsulation of one optional last action to execute at the end of the program

50.  trait Loop[M[_], R, A, B, C] extends AnyRef

    Generalisation of Recurse and StateRecurse

    Generalisation of Recurse and StateRecurse

    The loop defines some state with an initial value which is maintained at each step of the interpretation.

    A is the type of Eff values to interpret, and B is the result of the interpretation (generally an other Eff value)

    C is the type of result for "last" actions.

    - the interpretation of a Pure value either returns the final result or possibly one more Eff value to interpret

    - onEffect interprets one effect and possibly uses the continuation to produce the next value to interpret. If no X can be used to run the continuation we might just output one final B value

    • onLastEffect interprets the last effect of an Eff value. The only difference with onEffect is the fact that last actions return Unit values (and not A values)
    • onApplicativeEff interprets a list of effects and possibly uses the continuation to get to the next value to interpret. If no interpretation can be done, a B value might be returned
    • onLastApplicativeEffect does the same thing for last actions
51.  trait Member[T[_], R] extends MemberInOut[T, R]

    Annotations

    @implicitNotFound( ... )

52.  trait MemberIn[T[_], R] extends AnyRef

    Annotations

    @implicitNotFound( ... )

53.  trait MemberInLower1 extends MemberInLower2
54.  trait MemberInLower2 extends MemberInLower3
55.  trait MemberInLower3 extends MemberInLower4
56.  trait MemberInLower4 extends MemberInLower5
57.  trait MemberInLower5 extends AnyRef
58.  trait MemberInOut[T[_], R] extends MemberIn[T, R]

    Annotations

    @implicitNotFound( ... )

59.  trait MemberInOutLower1 extends MemberInOutLower2
60.  trait MemberInOutLower2 extends MemberInOutLower3
61.  trait MemberInOutLower3 extends MemberInOutLower4
62.  trait MemberInOutLower4 extends MemberInOutLower5
63.  trait MemberInOutLower5 extends AnyRef
64.  trait MemberLower1 extends MemberLower2
65.  trait MemberLower10 extends MemberLower11
66.  trait MemberLower11 extends MemberLower12
67.  trait MemberLower12 extends MemberLower13
68.  trait MemberLower13 extends MemberLower14
69.  trait MemberLower14 extends MemberLower15
70.  trait MemberLower15 extends MemberLower16
71.  trait MemberLower16 extends MemberLower17
72.  trait MemberLower17 extends MemberLower18
73.  trait MemberLower18 extends MemberLower19
74.  trait MemberLower19 extends AnyRef
75.  trait MemberLower2 extends MemberLower3
76.  trait MemberLower3 extends MemberLower4
77.  trait MemberLower4 extends MemberLower5
78.  trait MemberLower5 extends MemberLower6
79.  trait MemberLower6 extends MemberLower7
80.  trait MemberLower7 extends MemberLower8
81.  trait MemberLower8 extends MemberLower9
82.  trait MemberLower9 extends MemberLower10
83.  case class Memoized[T](t: () ⇒ T) extends Evaluated[T] with Product with Serializable
84.  class NoFx extends Fx

    The "empty" tree of effects

85.  case class Pure[R, A](value: A, last: Last[R] = Last.none[R]) extends Eff[R, A] with Product with Serializable
86.  trait Recurse[M[_], R, A] extends AnyRef

    Helper trait for computations which might produce several M[X] in a stack of effects.

    Helper trait for computations which might produce several M[X] in a stack of effects.

    Either we can produce an X to pass to a continuation or we're done

    For the applicative case we expect to be able to traverse a list of effects and return an effect of a list of results OR completely consume the effect and return a pure list of values

87.  sealed trait Safe[A] extends AnyRef

    The Safe type is a mix of a ThrowableEither / Eval effect and a writer effect to collect finalizer failures

88.  trait SafeCreation extends SafeTypes
89.  trait SafeEffect extends SafeCreation with SafeInterpretation
90.  trait SafeInterpretation extends SafeCreation
91.  trait SafeTypes extends AnyRef
92.  trait SequenceCached[M[_]] extends AnyRef

    type class for effects which can be cached in a SequenceCache

93.  trait SideEffect[T[_]] extends AnyRef
94.  trait StatelessLoop[M[_], R, A, B, C] extends AnyRef

    Generalisation of Recurse

95.  final case class TimedFuture[A](callback: (ExecutorServices) ⇒ Future[A], timeout: Option[FiniteDuration] = None) extends Product with Serializable
96.  trait Translate[T[_], U] extends AnyRef

    trait for translating one effect into other ones in the same stack

97.  sealed trait Union[+R, A] extends AnyRef

    Union represents one effect T[_] embedded in a tree of possible effects R

    Union represents one effect T[_] embedded in a tree of possible effects R

    Since the effect tree is represented with the following cases:

    • Fx1[T]
    • Fx2[T1, T2]
    • Fx3[T1, T2, T3]
    • FxAppend[L, R]

    We have the corresponding Union cases. For example T2 is in the "middle" of Fx3[T1, T2, T3] so creating a Union object for that effect uses Union3M

98.  case class Union1[T[_], A](ta: T[A]) extends Union[Fx1[T], A] with Product with Serializable
99.  sealed trait Union2[R, A] extends Union[R, A]
100.  case class Union2L[L[_], R[_], A](t: L[A]) extends Union2[Fx2[L, R], A] with Product with Serializable
101.  case class Union2R[L[_], R[_], A](t: R[A]) extends Union2[Fx2[L, R], A] with Product with Serializable
102.  sealed trait Union3[R, A] extends Union[R, A]
103.  case class Union3L[L[_], M[_], R[_], A](t: L[A]) extends Union3[Fx3[L, M, R], A] with Product with Serializable
104.  case class Union3M[L[_], M[_], R[_], A](t: M[A]) extends Union3[Fx3[L, M, R], A] with Product with Serializable
105.  case class Union3R[L[_], M[_], R[_], A](t: R[A]) extends Union3[Fx3[L, M, R], A] with Product with Serializable
106.  sealed trait UnionAppend[R, A] extends Union[R, A]
107.  case class UnionAppendL[L, R, A](t: Union[L, A]) extends UnionAppend[FxAppend[L, R], A] with Product with Serializable
108.  case class UnionAppendR[L, R, A](t: Union[R, A]) extends UnionAppend[FxAppend[L, R], A] with Product with Serializable
109.  trait UnionInto[R, S] extends AnyRef
110.  case class Unions[R, A](first: Union[R, A], rest: List[Union[R, Any]]) extends Product with Serializable

     A non-empty list of Unions.

     A non-empty list of Unions.

     It is only partially typed, we just keep track of the type of the first object

111.  trait Write[T[_], O] extends AnyRef
112.  case class Writer[O, A](value: O, a: A) extends Product with Serializable
113.  trait WriterCreation extends AnyRef
114.  trait WriterEffect extends WriterCreation with WriterInterpretation

     Effect for logging values alongside computations

     Effect for logging values alongside computations

     Compared to traditional Writer monad which accumulates values by default this effect can be interpreted in different ways:

     • log values to the console or to a file as soon as they are produced
     • accumulate values in a list
115.  trait WriterInterpretation extends AnyRef
116.  type |=[M[_], R] = MemberIn[M, R]