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final case class Error(error: Throwable) extends Eager[Nothing] with Product with Serializable

Constructs an eager Coeval instance for a result that represents an error.

Source
Coeval.scala
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  1. Error
  2. Eager
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  5. Coeval
  6. Serializable
  7. Function0
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Instance Constructors

  1. new Error(error: Throwable)

Value Members

  1. final def !=(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  2. final def ##: Int
    Definition Classes
    AnyRef → Any
  3. final def *>[B](that: Coeval[B]): Coeval[B]

    Runs this coeval first and then, when successful, the given coeval.

    Runs this coeval first and then, when successful, the given coeval. Returns the result of the given coeval.

    Example:

    val combined = Coeval{println("first"); "first"} *> Coeval{println("second"); "second"}
    // Prints "first" and then "second"
    // Result value will be "second"
    Definition Classes
    Coeval
  4. final def <*[B](that: Coeval[B]): Coeval[Nothing]

    Runs this coeval first and then, when successful, the given coeval.

    Runs this coeval first and then, when successful, the given coeval. Returns the result of this coeval.

    Example:

    val combined = Coeval{println("first"); "first"} <* Coeval{println("second"); "second"}
    // Prints "first" and then "second"
    // Result value will be "first"
    Definition Classes
    Coeval
  5. final def ==(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  6. final def >>[B](that: => Coeval[B]): Coeval[B]

    Runs this underlying computation first and then, when successful, the given one.

    Runs this underlying computation first and then, when successful, the given one. Returns the result of the given underlying computation.

    Example:

    val combined = Coeval{println("first"); "first"} >> Coeval{println("second"); "second"}
    // Prints "first" and then "second"
    // Result value will be "second"
    Definition Classes
    Coeval
  7. def apply(): Nothing

    Evaluates the underlying computation and returns the result.

    Evaluates the underlying computation and returns the result.

    NOTE: this can throw exceptions.

    // For didactic purposes, don't do shared vars at home :-)
    var i = 0
    val fa = Coeval { i += 1; i }
    
    fa() // => 1
    fa() // => 2
    fa() // => 3

    UNSAFE — this operation can trigger the execution of side effects, which break referential transparency and is thus not a pure function.

    In FP code use with care, suspended in another Coeval or Task, or at the edge of the FP program.

    Definition Classes
    ErrorCoeval → Function0
  8. final def as[B](b: B): Coeval[B]

    Returns this coeval mapped to the supplied value.

    Returns this coeval mapped to the supplied value.

    Definition Classes
    Coeval
  9. final def asInstanceOf[T0]: T0
    Definition Classes
    Any
  10. final def attempt: Coeval[Either[Throwable, Nothing]]

    Creates a new Coeval that will expose any triggered error from the source.

    Creates a new Coeval that will expose any triggered error from the source.

    val fa: Coeval[Int] =
      Coeval.raiseError[Int](new RuntimeException("dummy"))
    
    val fe: Coeval[Either[Throwable, Int]] =
      fa.attempt
    
    fe.map {
      case Left(_) => Int.MaxValue
      case Right(v) => v
    }

    By exposing errors by lifting the Coeval's result into an Either value, we can handle those errors in flatMap transformations.

    Also see materialize for working with Scala's Try or redeemWith for an alternative.

    Definition Classes
    Coeval
  11. final def bracket[B](use: (Nothing) => Coeval[B])(release: (Nothing) => Coeval[Unit]): Coeval[B]

    Returns a task that treats the source as the acquisition of a resource, which is then exploited by the use function and then released.

    Returns a task that treats the source as the acquisition of a resource, which is then exploited by the use function and then released.

    The bracket operation is the equivalent of the try {} finally {} statements from mainstream languages, installing the necessary exception handler to release the resource in the event of an exception being raised during the computation. If an exception is raised, then bracket will re-raise the exception after performing the release.

    Example:

    import java.io._
    
    def readFile(file: File): Coeval[String] = {
      // Opening a file handle for reading text
      val acquire = Coeval.eval(new BufferedReader(
        new InputStreamReader(new FileInputStream(file), "utf-8")
      ))
    
      acquire.bracket { in =>
        // Usage part
        Coeval.eval {
          // Yes, ugly Java, non-FP loop;
          // side-effects are suspended though
          var line: String = ""
          val buff = new StringBuilder()
          while (line != null) {
            line = in.readLine()
            if (line != null) buff.append(line)
          }
          buff.toString()
        }
      } { in =>
        // The release part
        Coeval.eval(in.close())
      }
    }

    NOTE on error handling: one big difference versus try {} finally {} is that, in case both the release function and the use function throws, the error raised by use gets signaled and the error raised by release gets reported with System.err for Coeval or with Scheduler.reportFailure for Task.

    For example:

    Coeval("resource").bracket { _ =>
      // use
      Coeval.raiseError(new RuntimeException("Foo"))
    } { _ =>
      // release
      Coeval.raiseError(new RuntimeException("Bar"))
    }

    In this case the error signaled downstream is "Foo", while the "Bar" error gets reported. This is consistent with the behavior of Haskell's bracket operation and NOT with try {} finally {} from Scala, Java or JavaScript.

    use

    is a function that evaluates the resource yielded by the source, yielding a result that will get generated by the task returned by this bracket function

    release

    is a function that gets called after use terminates, either normally or in error, receiving as input the resource that needs to be released

    Definition Classes
    Coeval
    See also

    bracketCase and bracketE

  12. final def bracketCase[B](use: (Nothing) => Coeval[B])(release: (Nothing, ExitCase[Throwable]) => Coeval[Unit]): Coeval[B]

    Returns a new task that treats the source task as the acquisition of a resource, which is then exploited by the use function and then released, with the possibility of distinguishing between successful completion and failure, such that an appropriate release of resources can be executed.

    Returns a new task that treats the source task as the acquisition of a resource, which is then exploited by the use function and then released, with the possibility of distinguishing between successful completion and failure, such that an appropriate release of resources can be executed.

    The bracketCase operation is the equivalent of try {} catch {} finally {} statements from mainstream languages when used for the acquisition and release of resources.

    The bracketCase operation installs the necessary exception handler to release the resource in the event of an exception being raised during the computation.

    In comparison with the simpler bracket version, this one allows the caller to differentiate between normal termination and termination in error via an ExitCase parameter.

    use

    is a function that evaluates the resource yielded by the source, yielding a result that will get generated by this function on evaluation

    release

    is a function that gets called after use terminates, either normally or in error, receiving as input the resource that needs that needs release, along with the result of use

    Definition Classes
    Coeval
    See also

    bracket and bracketE

  13. final def bracketE[B](use: (Nothing) => Coeval[B])(release: (Nothing, Either[Throwable, B]) => Coeval[Unit]): Coeval[B]

    Returns a task that treats the source task as the acquisition of a resource, which is then exploited by the use function and then released, with the possibility of distinguishing between successful termination and error, such that an appropriate release of resources can be executed.

    Returns a task that treats the source task as the acquisition of a resource, which is then exploited by the use function and then released, with the possibility of distinguishing between successful termination and error, such that an appropriate release of resources can be executed.

    The bracket operation is the equivalent of the try {} finally {} statements from mainstream languages, installing the necessary exception handler to release the resource in the event of an exception being raised during the computation. If an exception is raised, then bracket will re-raise the exception after performing the release.

    The release function receives as input:

    • Left(error) in case use terminated with an error
    • Right(b) in case of success

    NOTE on error handling: one big difference versus try {} finally {} is that, in case both the release function and the use function throws, the error raised by use gets signaled and the error raised by release gets reported with System.err for Coeval or with Scheduler.reportFailure for Task.

    For example:

    Coeval("resource").bracket { _ =>
      // use
      Coeval.raiseError(new RuntimeException("Foo"))
    } { _ =>
      // release
      Coeval.raiseError(new RuntimeException("Bar"))
    }

    In this case the error signaled downstream is "Foo", while the "Bar" error gets reported. This is consistent with the behavior of Haskell's bracket operation and NOT with try {} finally {} from Scala, Java or JavaScript.

    use

    is a function that evaluates the resource yielded by the source, yielding a result that will get generated by this function on evaluation

    release

    is a function that gets called after use terminates, either normally or in error, receiving as input the resource that needs that needs release, along with the result of use

    Definition Classes
    Coeval
    See also

    bracket and bracketCase

  14. def clone(): AnyRef
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.CloneNotSupportedException]) @native() @HotSpotIntrinsicCandidate()
  15. final def dematerialize[B](implicit ev: <:<[Nothing, Try[B]]): Coeval[B]

    Dematerializes the source's result from a Try.

    Dematerializes the source's result from a Try.

    This equivalence always holds:

    fa.materialize.dematerialize <-> fa

    Definition Classes
    Coeval
  16. final def doOnFinish(f: (Option[Throwable]) => Coeval[Unit]): Coeval[Nothing]

    Returns a new Coeval in which f is scheduled to be run on completion.

    Returns a new Coeval in which f is scheduled to be run on completion. This would typically be used to release any resources acquired by this Coeval.

    Definition Classes
    Coeval
  17. final def eq(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  18. val error: Throwable
  19. final def failed: Coeval[Throwable]

    Returns a failed projection of this coeval.

    Returns a failed projection of this coeval.

    The failed projection is a Coeval holding a value of type Throwable, emitting the error yielded by the source, in case the source fails, otherwise if the source succeeds the result will fail with a NoSuchElementException.

    Definition Classes
    Coeval
  20. final def flatMap[B](f: (Nothing) => Coeval[B]): Coeval[B]

    Creates a new Coeval by applying a function to the successful result of the source, and returns a new instance equivalent to the result of the function.

    Creates a new Coeval by applying a function to the successful result of the source, and returns a new instance equivalent to the result of the function.

    The application of flatMap is always lazy and because of the implementation it is memory safe and thus it can be used in recursive loops.

    Sample:

    import scala.util.Random
    
    def randomEven: Coeval[Int] =
      Coeval(Random.nextInt()).flatMap { x =>
        if (x < 0 || x % 2 == 1)
          randomEven // retry
        else
          Coeval.now(x)
      }
    Definition Classes
    Coeval
  21. final def flatMapLoop[S](seed: S)(f: (Nothing, S, (S) => Coeval[S]) => Coeval[S]): Coeval[S]

    Describes flatMap-driven loops, as an alternative to recursive functions.

    Describes flatMap-driven loops, as an alternative to recursive functions.

    Sample:

    import scala.util.Random
    
    val random = Coeval(Random.nextInt())
    val loop = random.flatMapLoop(Vector.empty[Int]) { (a, list, continue) =>
      val newList = list :+ a
      if (newList.length < 5)
        continue(newList)
      else
        Coeval.now(newList)
    }
    seed

    initializes the result of the loop

    f

    is the function that updates the result on each iteration, returning a Coeval.

    returns

    a new Coeval that contains the result of the loop.

    Definition Classes
    Coeval
  22. final def flatten[B](implicit ev: <:<[Nothing, Coeval[B]]): Coeval[B]

    Given a source Coeval that emits another Coeval, this function flattens the result, returning a Coeval equivalent to the emitted Coeval by the source.

    Given a source Coeval that emits another Coeval, this function flattens the result, returning a Coeval equivalent to the emitted Coeval by the source.

    This equivalence with flatMap always holds:

    fa.flatten <-> fa.flatMap(x => x)

    Definition Classes
    Coeval
  23. final def foreach(f: (Nothing) => Unit): Unit

    Triggers the evaluation of the source, executing the given function for the generated element.

    Triggers the evaluation of the source, executing the given function for the generated element.

    The application of this function has strict behavior, as the coeval is immediately executed.

    Definition Classes
    Coeval
  24. final def foreachL(f: (Nothing) => Unit): Coeval[Unit]

    Returns a new task that upon evaluation will execute the given function for the generated element, transforming the source into a Coeval[Unit].

    Returns a new task that upon evaluation will execute the given function for the generated element, transforming the source into a Coeval[Unit].

    Similar in spirit with normal foreach, but lazy, as obviously nothing gets executed at this point.

    Definition Classes
    Coeval
  25. final def getClass(): Class[_ <: AnyRef]
    Definition Classes
    AnyRef → Any
    Annotations
    @native() @HotSpotIntrinsicCandidate()
  26. final def guarantee(finalizer: Coeval[Unit]): Coeval[Nothing]

    Executes the given finalizer when the source is finished, either in success or in error, or if canceled.

    Executes the given finalizer when the source is finished, either in success or in error, or if canceled.

    This variant of guaranteeCase evaluates the given finalizer regardless of how the source gets terminated:

    • normal completion
    • completion in error
    • cancellation

    As best practice, it's not a good idea to release resources via guaranteeCase in polymorphic code. Prefer bracket for the acquisition and release of resources.

    Definition Classes
    Coeval
    See also

    guaranteeCase for the version that can discriminate between termination conditions

    bracket for the more general operation

  27. final def guaranteeCase(finalizer: (ExitCase[Throwable]) => Coeval[Unit]): Coeval[Nothing]

    Executes the given finalizer when the source is finished, either in success or in error, or if canceled, allowing for differentiating between exit conditions.

    Executes the given finalizer when the source is finished, either in success or in error, or if canceled, allowing for differentiating between exit conditions.

    This variant of guarantee injects an ExitCase in the provided function, allowing one to make a difference between:

    • normal completion
    • completion in error
    • cancellation

    As best practice, it's not a good idea to release resources via guaranteeCase in polymorphic code. Prefer bracketCase for the acquisition and release of resources.

    Definition Classes
    Coeval
    See also

    guarantee for the simpler version

    bracketCase for the more general operation

  28. final def isError: Boolean

    Returns true if result is an error.

    Returns true if result is an error.

    Definition Classes
    Eager
  29. final def isInstanceOf[T0]: Boolean
    Definition Classes
    Any
  30. final def isSuccess: Boolean

    Returns true if value is a successful one.

    Returns true if value is a successful one.

    Definition Classes
    Eager
  31. final def map[B](f: (Nothing) => B): Coeval[B]

    Returns a new Coeval that applies the mapping function to the element emitted by the source.

    Returns a new Coeval that applies the mapping function to the element emitted by the source.

    Can be used for specifying a (lazy) transformation to the result of the source.

    This equivalence with flatMap always holds:

    fa.map(f) <-> fa.flatMap(x => Coeval.pure(f(x)))

    Definition Classes
    Coeval
  32. final def materialize: Coeval[Try[Nothing]]

    Creates a new Coeval that will expose any triggered error from the source.

    Creates a new Coeval that will expose any triggered error from the source.

    Also see attempt for working with Scala's Either or redeemWith for an alternative.

    Definition Classes
    Coeval
  33. final def memoize: Coeval[Nothing]

    Memoizes (caches) the result of the source and reuses it on subsequent invocations of value.

    Memoizes (caches) the result of the source and reuses it on subsequent invocations of value.

    The resulting coeval will be idempotent, meaning that evaluating the resulting coeval multiple times will have the same effect as evaluating it once.

    UNSAFE — this operation allocates a shared, mutable reference, which can break in certain cases referential transparency, even if this operation guarantees idempotency (i.e. referential transparency implies idempotency, but idempotency does not imply referential transparency).

    The allocation of a mutable reference is known to be a side effect, thus breaking referential transparency, even if calling this method does not trigger the evaluation of side effects suspended by the source.

    Use with care. Sometimes it's easier to just keep a shared, memoized reference to some connection, but keep in mind it might be better to pass such a reference around as a parameter.

    Definition Classes
    Coeval
    Annotations
    @UnsafeBecauseImpure()
    See also

    memoizeOnSuccess for a version that only caches successful results

  34. final def memoizeOnSuccess: Coeval[Nothing]

    Memoizes (cache) the successful result of the source and reuses it on subsequent invocations of value.

    Memoizes (cache) the successful result of the source and reuses it on subsequent invocations of value. Thrown exceptions are not cached.

    The resulting coeval will be idempotent, but only if the result is successful.

    UNSAFE — this operation allocates a shared, mutable reference, which can break in certain cases referential transparency, even if this operation guarantees idempotency (i.e. referential transparency implies idempotency, but idempotency does not imply referential transparency).

    The allocation of a mutable reference is known to be a side effect, thus breaking referential transparency, even if calling this method does not trigger the evaluation of side effects suspended by the source.

    Use with care. Sometimes it's easier to just keep a shared, memoized reference to some connection, but keep in mind it might be better to pass such a reference around as a parameter.

    Definition Classes
    Coeval
    Annotations
    @UnsafeBecauseImpure()
    See also

    memoize for a version that caches both successful results and failures

  35. final def ne(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  36. final def notify(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native() @HotSpotIntrinsicCandidate()
  37. final def notifyAll(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native() @HotSpotIntrinsicCandidate()
  38. final def onErrorFallbackTo[B >: Nothing](that: Coeval[B]): Coeval[B]

    Creates a new coeval that in case of error will fallback to the given backup coeval.

    Creates a new coeval that in case of error will fallback to the given backup coeval.

    Definition Classes
    Coeval
  39. final def onErrorHandle[U >: Nothing](f: (Throwable) => U): Coeval[U]

    Creates a new coeval that will handle any matching throwable that this coeval might emit.

    Creates a new coeval that will handle any matching throwable that this coeval might emit.

    See onErrorRecover for the version that takes a partial function.

    Definition Classes
    Coeval
  40. final def onErrorHandleWith[B >: Nothing](f: (Throwable) => Coeval[B]): Coeval[B]

    Creates a new coeval that will handle any matching throwable that this coeval might emit by executing another coeval.

    Creates a new coeval that will handle any matching throwable that this coeval might emit by executing another coeval.

    See onErrorRecoverWith for the version that takes a partial function.

    Definition Classes
    Coeval
  41. final def onErrorRecover[U >: Nothing](pf: PartialFunction[Throwable, U]): Coeval[U]

    Creates a new coeval that on error will try to map the error to another value using the provided partial function.

    Creates a new coeval that on error will try to map the error to another value using the provided partial function.

    See onErrorHandle for the version that takes a total function.

    Definition Classes
    Coeval
  42. final def onErrorRecoverWith[B >: Nothing](pf: PartialFunction[Throwable, Coeval[B]]): Coeval[B]

    Creates a new coeval that will try recovering from an error by matching it with another coeval using the given partial function.

    Creates a new coeval that will try recovering from an error by matching it with another coeval using the given partial function.

    See onErrorHandleWith for the version that takes a total function.

    Definition Classes
    Coeval
  43. final def onErrorRestart(maxRetries: Long): Coeval[Nothing]

    Creates a new coeval that in case of error will retry executing the source again and again, until it succeeds.

    Creates a new coeval that in case of error will retry executing the source again and again, until it succeeds.

    In case of continuous failure the total number of executions will be maxRetries + 1.

    Definition Classes
    Coeval
  44. final def onErrorRestartIf(p: (Throwable) => Boolean): Coeval[Nothing]

    Creates a new coeval that in case of error will retry executing the source again and again, until it succeeds.

    Creates a new coeval that in case of error will retry executing the source again and again, until it succeeds.

    In case of continuous failure the total number of executions will be maxRetries + 1.

    Definition Classes
    Coeval
  45. final def onErrorRestartLoop[S, B >: Nothing](initial: S)(f: (Throwable, S, (S) => Coeval[B]) => Coeval[B]): Coeval[B]

    On error restarts the source with a customizable restart loop.

    On error restarts the source with a customizable restart loop.

    This operation keeps an internal state, with a start value, an internal state that gets evolved and based on which the next step gets decided, e.g. should it restart, or should it give up and rethrow the current error.

    Example that implements a simple retry policy that retries for a maximum of 10 times before giving up:

    import scala.util.Random
    
    val fa = Coeval {
      if (Random.nextInt(20) > 10)
        throw new RuntimeException("boo")
      else 78
    }
    
    fa.onErrorRestartLoop(10) { (err, maxRetries, retry) =>
      if (maxRetries > 0)
        // Do next retry please
        retry(maxRetries - 1)
      else
        // No retries left, rethrow the error
        Coeval.raiseError(err)
    }

    The given function injects the following parameters:

    1. error reference that was thrown 2. the current state, based on which a decision for the retry is made 3. retry: S => Task[B] function that schedules the next retry
    initial

    is the initial state used to determine the next on error retry cycle

    f

    is a function that injects the current error, state, a function that can signal a retry is to be made and returns the next coeval

    Definition Classes
    Coeval
  46. def productElementNames: Iterator[String]
    Definition Classes
    Product
  47. def redeem[B](recover: (Throwable) => B, map: (Nothing) => B): Coeval[B]

    Returns a new value that transforms the result of the source, given the recover or map functions, which get executed depending on whether the result is successful or if it ends in error.

    Returns a new value that transforms the result of the source, given the recover or map functions, which get executed depending on whether the result is successful or if it ends in error.

    This is an optimization on usage of attempt and map, this equivalence being true:

    coeval.redeem(recover, map) <-> coeval.attempt.map(_.fold(recover, map))

    Usage of redeem subsumes onErrorHandle because:

    coeval.redeem(fe, id) <-> coeval.onErrorHandle(fe)

    recover

    is a function used for error recover in case the source ends in error

    map

    is a function used for mapping the result of the source in case it ends in success

    Definition Classes
    Coeval
  48. def redeemWith[B](recover: (Throwable) => Coeval[B], bind: (Nothing) => Coeval[B]): Coeval[B]

    Returns a new value that transforms the result of the source, given the recover or bind functions, which get executed depending on whether the result is successful or if it ends in error.

    Returns a new value that transforms the result of the source, given the recover or bind functions, which get executed depending on whether the result is successful or if it ends in error.

    This is an optimization on usage of attempt and flatMap, this equivalence being available:

    coeval.redeemWith(recover, bind) <-> coeval.attempt.flatMap(_.fold(recover, bind))

    Usage of redeemWith subsumes onErrorHandleWith because:

    coeval.redeemWith(fe, F.pure) <-> coeval.onErrorHandleWith(fe)

    Usage of redeemWith also subsumes flatMap because:

    coeval.redeemWith(Coeval.raiseError, fs) <-> coeval.flatMap(fs)

    recover

    is the function that gets called to recover the source in case of error

    bind

    is the function that gets to transform the source in case of success

    Definition Classes
    Coeval
  49. final def restartUntil(p: (Nothing) => Boolean): Coeval[Nothing]

    Given a predicate function, keep retrying the coeval until the function returns true.

    Given a predicate function, keep retrying the coeval until the function returns true.

    Definition Classes
    Coeval
  50. def run(): Error

    Evaluates the underlying computation, reducing this Coeval to a Coeval.Eager value, with successful results being signaled with Coeval.Now and failures with Coeval.Error.

    Evaluates the underlying computation, reducing this Coeval to a Coeval.Eager value, with successful results being signaled with Coeval.Now and failures with Coeval.Error.

    val fa = Coeval.eval(10 * 2)
    
    fa.run() match {
      case Coeval.Now(value) =>
        println("Success: " + value)
      case Coeval.Error(e) =>
        e.printStackTrace()
    }

    See [.runAttempt()]] for working with Either values and [.runTry()]] for working with Try values. See apply for a partial function (that may throw exceptions in case of failure).

    UNSAFE — this operation can trigger the execution of side effects, which break referential transparency and is thus not a pure function.

    In FP code use with care, suspended in another Coeval or Task, or at the edge of the FP program.

    Definition Classes
    ErrorCoeval
  51. def runAttempt(): Either[Throwable, Nothing]

    Evaluates the underlying computation and returns the result or any triggered errors as a Scala Either, where Right(_) is for successful values and Left(_) is for thrown errors.

    Evaluates the underlying computation and returns the result or any triggered errors as a Scala Either, where Right(_) is for successful values and Left(_) is for thrown errors.

    val fa = Coeval(10 * 2)
    
    fa.runAttempt() match {
      case Right(value) =>
        println("Success: " + value)
      case Left(e) =>
        e.printStackTrace()
    }

    See run for working with Coeval.Eager values and [.runTry()]] for working with Try values. See apply for a partial function (that may throw exceptions in case of failure).

    UNSAFE — this operation can trigger the execution of side effects, which break referential transparency and is thus not a pure function.

    In FP code use with care, suspended in another Coeval or Task, or at the edge of the FP program.

    Definition Classes
    ErrorCoeval
  52. def runTry(): Try[Nothing]

    Evaluates the underlying computation and returns the result or any triggered errors as a scala.util.Try.

    Evaluates the underlying computation and returns the result or any triggered errors as a scala.util.Try.

    import scala.util._
    
    val fa = Coeval(10 * 2)
    
    fa.runTry() match {
      case Success(value) =>
        println("Success: " + value)
      case Failure(e) =>
        e.printStackTrace()
    }

    See run for working with Coeval.Eager values and [.runAttempt()]] for working with Either values. See apply for a partial function (that may throw exceptions in case of failure).

    UNSAFE — this operation can trigger the execution of side effects, which break referential transparency and is thus not a pure function.

    In FP code use with care, suspended in another Coeval or Task, or at the edge of the FP program.

    Definition Classes
    ErrorCoeval
  53. final def synchronized[T0](arg0: => T0): T0
    Definition Classes
    AnyRef
  54. final def tapError[B](f: (Throwable) => Coeval[B]): Coeval[Nothing]

    Creates a new Coeval that will run the given function in case of error and raise the original error in case the provided function is successful.

    Creates a new Coeval that will run the given function in case of error and raise the original error in case the provided function is successful.

    Example:

    // will result in Left("Error")
    Coeval
       .raiseError(new RuntimeException("Error"))
       .tapError(err => Coeval(err))

    If provided function returns an error then the resulting coeval will raise that error instead.

    Example:

    // will result in Left("Error2")
    Coeval
       .raiseError(new RuntimeException("Error1"))
       .tapError(err => Coeval.raiseError(new RuntimeException("Error2")))
    Definition Classes
    Coeval
  55. final def tapEval[B](f: (Nothing) => Coeval[B]): Coeval[Nothing]

    Creates a new Coeval that will run the given function on the success and return the original value.

    Creates a new Coeval that will run the given function on the success and return the original value.

    Definition Classes
    Coeval
  56. final def to[F[_]](implicit F: CoevalLift[F]): F[Nothing]

    Converts the source Coeval into any F[_] that implements cats.effect.Sync.

    Converts the source Coeval into any F[_] that implements cats.effect.Sync.

    For example it can work with cats.effect.IO:

    import cats._
    import cats.effect._
    
    val source = Coeval { 1 + 1 }
    
    val asIO: IO[Int]     = source.to[IO]
    val asEval: Eval[Int] = source.to[Eval]
    val asTask: Task[Int] = source.to[Task]
    Definition Classes
    Coeval
  57. final def toEither: Either[Throwable, Nothing]

    Converts this Eager value into a scala.Either.

    Converts this Eager value into a scala.Either.

    Definition Classes
    Eager
  58. def toString(): String
    Definition Classes
    Coeval → Function0 → AnyRef → Any
  59. final def toSync[F[_]](implicit F: Sync[F]): F[Nothing]

    Converts the source to any value that implements cats.effect.Sync.

    Converts the source to any value that implements cats.effect.Sync.

    Prefer to use to, this method is provided in order to force the usage of cats.effect.Sync instances (instead of CoevalLift).

    Definition Classes
    Coeval
  60. final def toTry: Try[Nothing]

    Converts this Eager value into a scala.util.Try.

    Converts this Eager value into a scala.util.Try.

    Definition Classes
    Eager
  61. def value(): Nothing

    Evaluates the underlying computation and returns the result.

    Evaluates the underlying computation and returns the result.

    NOTE: this can throw exceptions.

    Alias for apply.

    UNSAFE — this operation can trigger the execution of side effects, which break referential transparency and is thus not a pure function.

    In FP code use with care, suspended in another Coeval or Task, or at the edge of the FP program.

    Definition Classes
    Coeval
    Annotations
    @UnsafeBecauseImpure()
  62. final def void: Coeval[Unit]

    Returns this coeval mapped to unit

    Returns this coeval mapped to unit

    Definition Classes
    Coeval
  63. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  64. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException]) @native()
  65. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  66. final def zip[B](that: Coeval[B]): Coeval[(Nothing, B)]

    Zips the values of this and that coeval, and creates a new coeval that will emit the tuple of their results.

    Zips the values of this and that coeval, and creates a new coeval that will emit the tuple of their results.

    Definition Classes
    Coeval
  67. final def zipMap[B, C](that: Coeval[B])(f: (Nothing, B) => C): Coeval[C]

    Zips the values of this and that and applies the given mapping function on their results.

    Zips the values of this and that and applies the given mapping function on their results.

    Definition Classes
    Coeval

Deprecated Value Members

  1. def finalize(): Unit
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.Throwable]) @Deprecated
    Deprecated
  2. final def transform[R](fa: (Nothing) => R, fe: (Throwable) => R): Coeval[R]

    Deprecated — use redeem instead.

    Deprecated — use redeem instead.

    Coeval.redeem is the same operation, but with a different name and the function parameters in an inverted order, to make it consistent with fold on Either and others (i.e. the function for error recovery is at the left).

    Definition Classes
    Coeval
    Annotations
    @deprecated
    Deprecated

    (Since version 3.0.0-RC2) Please use Coeval.redeem

  3. final def transformWith[R](fa: (Nothing) => Coeval[R], fe: (Throwable) => Coeval[R]): Coeval[R]

    Deprecated — use redeemWith instead.

    Deprecated — use redeemWith instead.

    Coeval.redeemWith is the same operation, but with a different name and the function parameters in an inverted order, to make it consistent with fold on Either and others (i.e. the function for error recovery is at the left).

    Definition Classes
    Coeval
    Annotations
    @deprecated
    Deprecated

    (Since version 3.0.0-RC2) Please use Coeval.redeemWith

Inherited from Eager[Nothing]

Inherited from Product

Inherited from Equals

Inherited from Coeval[Nothing]

Inherited from Serializable

Inherited from () => Nothing

Inherited from AnyRef

Inherited from Any

Ungrouped