Introducing the concept of eager laziness in a rudimentary way

eager_lazy_value.scala

package main

import scala.concurrent._
import ExecutionContext.Implicits.global
import scala.concurrent.duration.Duration
import java.util.Calendar

object LazyEagerValues {

    def toFuture[A, B](f: A => B): A => Future[B] = x => future { f(x) }

    def main(args: Array[String]): Unit = {
        traceThis("Starting")
        val is_normal = expensiveComputation(1)
        traceThis("is_normal 'done'")
        lazy val is_lazy = expensiveComputation(1)
        traceThis("is_lazy 'done'")
        val eager_lazy_aux = toFuture(expensiveComputation)(1)
        lazy val eager_lazy = Await.result(eager_lazy_aux, Duration.Inf)
        traceThis("eager lazy 'done'")
        traceThis(s"is normal: $is_normal")
        traceThis(s"is_lazy: $is_lazy")
        traceThis(s"eager_lazy: $eager_lazy")
    }

    def expensiveComputation(n: Int): Int = {
        Thread sleep 10000
        n + 1
    }

    // about laziness, no logger library, is there any by default in the language?
    def traceThis(s: String) = {
        println(s"${Calendar.getInstance().getTime()}: $s")
    }

}