我如何从Scalaz的未来中获得价值？

我有以下代码：

package functorapplication

import scalaz._
import Scalaz._
import scalaz.concurrent.Future

object FunctorApplication2 extends App {

  val f1 = Future(3)//(ec)
  val f2 = Future(4)//(ec)
  val f3 = Future(5)//(ec)
  val calculate = (a: Int) => (b: Int) => (c: Int) => a + b + c
  val area = f1 <*> (f2 <*> (f3 <*> Future(calculate)))//(ec))) // Future(12)

  //println(area)//BindSuspend(scalaz.concurrent.Future$$Lambda...
  println("starting")
  val summed = for {
    a <- area
  } yield {
    println(a)
  }
  area.map(value => println(value))

  //println(summed)//Suspend(scalaz.concurrent.Future$$Lambda...
  println("done")

}

关键是——在未来，对于理解或映射来说，似乎没有任何价值

我的问题是：我如何从Scalaz的未来中获得价值？

注:

这是我的scala版本

scalaVersion := "2.12.5",

这是我的scalaz版本

  "org.scalaz" %% "scalaz-core" % "7.2.26",
  "org.scalaz" %% "scalaz-concurrent" % "7.2.26",
  "org.scalaz" %% "scalaz-effect" % "7.2.26",
  "org.scalaz" %% "scalaz-iteratee" % "7.2.26"

---

如果您持有类型为

Future[a]

的值，则您有资格在将来某个时间获得该值

• 类型为

  a

• 或者是一个错误，表示为类型为

  Throwable

  的值

因此，未来代表着潜在的未来价值。获得未来价值的唯一已知方法是等待它

import scala.concurrent._
import scala.concurrent.ExecutionContext.Implicits.global
import scala.concurrent.duration._

val f1 = Future(3)//(ec)
val f2 = Future(4)//(ec)
val f3 = Future(5)//(ec)

val calculate = (a: Int) => (b: Int) => (c: Int) => a + b + c

val area: Future[Int] = for {
  v1 <- f1 
  v2 <- f2 
  v3 <-f3 
} yield calculate(v1)(v2)(v3)

println("starting")

println("adding future side effect")
//this happens in the future
val withSideEffect = area.map(value => println("side-effect: " + value))

println("awaiting now")
//now, let's wait
println("Await: " + Await.ready(withSideEffect, Duration.Inf).value)

println("done")

import scala.concurrent._
import scala.concurrent.ExecutionContext.Implicits.global
import scala.concurrent.duration._

val f1 = Future(3)//(ec)
val f2 = Future(4)//(ec)
val f3 = Future(5)//(ec)

val calculate = (a: Int) => (b: Int) => (c: Int) => a + b + c

val area: Future[Int] = for {
  v1 <- f1 
  v2 <- f2 
  v3 <-f3 
} yield calculate(v1)(v2)(v3)

println("starting")

println("adding future side effect")
//this happens in the future
val withSideEffect = area.map(value => println("side-effect: " + value))

println("awaiting now")
//now, let's wait
println("Await: " + Await.ready(withSideEffect, Duration.Inf).value)

println("done")

starting
adding future side effect
awaiting now
side-effect: 12
Await: Some(Success(()))
done