Scala-Futures-Go

package main

import (
  "fmt"
  "time"
)

func expensiveOp() <-chan int {
  fmt.Println("expensiveOp...")
  time.Sleep(50000000)
  c := make(chan int, 1)
  c <- 1
  return c
}

func veryExpensiveOp(i int) <-chan int {
  fmt.Println("veryExpensiveOp...")
  time.Sleep(50000000)
  c := make(chan int, 1)
  c <- i + 1
  return c
}

/*
  def expensiveOp: Future[Int] = ???
  def veryExpensiveOp(i: Int): Future[Int] = ???
  for {
    v1 <- expensiveOp
    v2 <- veryExpensiveOp(v1)
 } yield v2
*/

func main() {
  result := make(chan int,1)
  fmt.Println("before goroutine")

  go func(c chan int) {
    v1 := <- expensiveOp()
    v2 := <- veryExpensiveOp(v1)
    c <- v2
  }(result)

  fmt.Println("after goroutine")
 
  select {
    case r := <- result:
      fmt.Println("inside select:",r)
      break
    default:
      fmt.Println("default")
  }
  fmt.Println("About to read the result")
  fmt.Println("Result = ", <-result)
  fmt.Println("Blocked by above channel read")
}