Interpret

The Interpret trait provides method to interpret (or "handle") effects.

An interpreter generally handles a given effect M and a value Eff[R, A] where M is a member of R.

The most general way of interpreting an effect is to implement the Interpreter trait for that effect and use the runInterpreter method. With the Interpreter trait you need to define:

what to do with pure values
what to do with an effect
what to do with a list of effects (the "applicative" case)
what to do with a "last" effect, in case of having side-effects to finalize resources (see the SafeEffect)

For each of those methods you get access to a continuation which you may or may not invoke to create the next effect in a sequence of effects. For example with the EitherEffect once you arrive on a Left value you don't trigger the continuation because there is no value to trigger it with.

There are also easier ways to define interpreters. The recurse method and the Recurser trait define:

onPure(a: A): B: how to map a pure value A to the result B
onEffect[X](mx: M[X]): X Either Eff[R, B]: either extract a value from the effect or return another effect
onApplicative[X](tx: T[M[X]]): T[X] Either M[T[X]]: either extract individual values from each effect or "sequence" the effect

Even simpler, the Translate trait does a translation from an effect M[X] to other effects in the stack.

There are also a few intercept methods to use an effect but still leave it in the stack

Linear Supertypes

AnyRef, Any

Known Subclasses

Interpret, interpret

Type Members

type of[F[_], G[_]] = AnyRef { type l[A] = F[G[A]] }

Value Members

final def !=(arg0: Any): Boolean

Definition Classes
AnyRef → Any
final def ##(): Int

Definition Classes
AnyRef → Any
final def ==(arg0: Any): Boolean

Definition Classes
AnyRef → Any
final def asInstanceOf[T0]: T0

Definition Classes
Any
def augment[R, T[_], O[_], A](eff: Eff[R, A])(w: Augment[T, O])(implicit m: MemberInOut[T, R]): Eff[prepend[O, R], A]

Interpret the effect T with a side-effect O (see the write method below)
def clone(): AnyRef

Attributes
protected[java.lang]
Definition Classes
AnyRef
Annotations
@throws( ... )
final def eq(arg0: AnyRef): Boolean

Definition Classes
AnyRef
def equals(arg0: Any): Boolean

Definition Classes
AnyRef → Any
def finalize(): Unit

Attributes
protected[java.lang]
Definition Classes
AnyRef
Annotations
@throws( classOf[java.lang.Throwable] )
final def getClass(): Class[_]

Definition Classes
AnyRef → Any
def hashCode(): Int

Definition Classes
AnyRef → Any
def intercept[R, T[_], A, B](e: Eff[R, A])(interpreter: Interpreter[T, R, A, B])(implicit m: /=[T, R]): Eff[R, B]
def interceptNat[R, T[_], A](effect: Eff[R, A])(nat: ~>[T, T])(implicit m: /=[T, R]): Eff[R, A]

Intercept the values for one effect and transform them into other values for the same effect
def interceptNatM[R, M[_], F[_], A](effect: Eff[R, A], nat: ~>[M, [A]M[F[A]]])(implicit m: MemberInOut[M, R], FT: Traverse[F], FM: Monad[F]): Eff[R, F[A]]

Intercept the values for one effect, emitting new values for the same effect inside a monad which is interleaved in
def interpretUnsafe[R, U, T[_], A](effect: Eff[R, A])(sideEffect: SideEffect[T])(implicit m: Aux[T, R, U]): Eff[U, A]

interpret an effect by running side-effects
final def isInstanceOf[T0]: Boolean

Definition Classes
Any
final def ne(arg0: AnyRef): Boolean

Definition Classes
AnyRef
final def notify(): Unit

Definition Classes
AnyRef
final def notifyAll(): Unit

Definition Classes
AnyRef
def recurse[R, U, T[_], A, B](e: Eff[R, A])(recurser: Recurser[T, U, A, B])(implicit m: Aux[T, R, U]): Eff[U, B]

Interpret an effect with a Recurser
def runInterpreter[R, U, T[_], A, B](e: Eff[R, A])(interpreter: Interpreter[T, U, A, B])(implicit m: Aux[T, R, U]): Eff[U, B]
final def synchronized[T0](arg0: ⇒ T0): T0

Definition Classes
AnyRef
def toString(): String

Definition Classes
AnyRef → Any
def transform[SR, BR, U, TS[_], TB[_], A](effect: Eff[SR, A], nat: ~>[TS, TB])(implicit sr: Aux[TS, SR, U], br: Aux[TB, BR, U]): Eff[BR, A]

transform an effect into another one using a natural transformation, leaving the rest of the stack untouched
def translate[R, U, T[_], A](effect: Eff[R, A])(tr: Translate[T, U])(implicit m: Aux[T, R, U]): Eff[U, A]

Translate one effect of the stack into some of the other effects in the stack
def translateInto[R, T[_], U, A](effect: Eff[R, A])(tr: Translate[T, U])(implicit t: /=[T, R], into: IntoPoly[R, U]): Eff[U, A]

Translate one effect of the stack into other effects in a larger stack
def translateNat[R, U, T[_], A](effects: Eff[R, A])(nat: ~>[T, [β$0$]Eff[U, β$0$]])(implicit m: Aux[T, R, U]): Eff[U, A]

Translate one effect of the stack into some of the other effects in the stack Using a natural transformation
final def wait(): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )
final def wait(arg0: Long, arg1: Int): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )
final def wait(arg0: Long): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )
def write[R, T[_], O, A](eff: Eff[R, A])(w: Write[T, O])(implicit m: MemberInOut[T, R]): Eff[prepend[[β$1$]WriterT[[A]A, O, β$1$], R], A]

For each effect T add some "log statements" O using the Writer effect

Related Docs: object Interpret | package eff

trait Interpret extends AnyRef

Type Members

type of[F[_], G[_]] = AnyRef { type l[A] = F[G[A]] }

Value Members

final def !=(arg0: Any): Boolean

final def ##(): Int

final def ==(arg0: Any): Boolean

final def asInstanceOf[T0]: T0

def augment[R, T[_], O[_], A](eff: Eff[R, A])(w: Augment[T, O])(implicit m: MemberInOut[T, R]): Eff[prepend[O, R], A]

def clone(): AnyRef

final def eq(arg0: AnyRef): Boolean

def equals(arg0: Any): Boolean

def finalize(): Unit

final def getClass(): Class[_]

def hashCode(): Int

def intercept[R, T[_], A, B](e: Eff[R, A])(interpreter: Interpreter[T, R, A, B])(implicit m: /=[T, R]): Eff[R, B]

def interceptNat[R, T[_], A](effect: Eff[R, A])(nat: ~>[T, T])(implicit m: /=[T, R]): Eff[R, A]

def interceptNatM[R, M[_], F[_], A](effect: Eff[R, A], nat: ~>[M, [A]M[F[A]]])(implicit m: MemberInOut[M, R], FT: Traverse[F], FM: Monad[F]): Eff[R, F[A]]

def interpretUnsafe[R, U, T[_], A](effect: Eff[R, A])(sideEffect: SideEffect[T])(implicit m: Aux[T, R, U]): Eff[U, A]

final def isInstanceOf[T0]: Boolean

final def ne(arg0: AnyRef): Boolean

final def notify(): Unit

final def notifyAll(): Unit

def recurse[R, U, T[_], A, B](e: Eff[R, A])(recurser: Recurser[T, U, A, B])(implicit m: Aux[T, R, U]): Eff[U, B]

def runInterpreter[R, U, T[_], A, B](e: Eff[R, A])(interpreter: Interpreter[T, U, A, B])(implicit m: Aux[T, R, U]): Eff[U, B]

final def synchronized[T0](arg0: ⇒ T0): T0

def toString(): String

def transform[SR, BR, U, TS[_], TB[_], A](effect: Eff[SR, A], nat: ~>[TS, TB])(implicit sr: Aux[TS, SR, U], br: Aux[TB, BR, U]): Eff[BR, A]

def translate[R, U, T[_], A](effect: Eff[R, A])(tr: Translate[T, U])(implicit m: Aux[T, R, U]): Eff[U, A]

def translateInto[R, T[_], U, A](effect: Eff[R, A])(tr: Translate[T, U])(implicit t: /=[T, R], into: IntoPoly[R, U]): Eff[U, A]

def translateNat[R, U, T[_], A](effects: Eff[R, A])(nat: ~>[T, [β$0$]Eff[U, β$0$]])(implicit m: Aux[T, R, U]): Eff[U, A]

final def wait(): Unit

final def wait(arg0: Long, arg1: Int): Unit

final def wait(arg0: Long): Unit

def write[R, T[_], O, A](eff: Eff[R, A])(w: Write[T, O])(implicit m: MemberInOut[T, R]): Eff[prepend[[β$1$]WriterT[[A]A, O, β$1$], R], A]

Inherited from AnyRef

Inherited from Any

Ungrouped