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// Iterators
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// $Id$

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object Test {

  def check_from: Int = {
    val it1 = Iterator.from(-1)
    val it2 = Iterator.from(0, -1)
    it1.next + it2.next
  }
  def check_range: Int = {
    val xs1 = Iterator.range(0, 10,  2) toList;
    val xs2 = Iterator.range(0, 10, -2) toList;
    val xs3 = Iterator.range(10, 0, -2) toList;
    val xs4 = Iterator.range(10, 0,  2) toList;
    val xs5 = Iterator.range(0, 10, 11) toList;
    xs1.length + xs2.length + xs3.length + xs4.length + xs5.length
  }

  def check_range2: Int = {
    val r1 = Iterator.range(0, 10)
    val r2 = Iterator.range(r1.start, r1.end, r1.step + 1)
    val r3 = Iterator.range(r1.end, r1.start, -r1.step)
    val r4 = Iterator.range(0, 10, 11)
    // 10 + 5 + 10 + 1
    r1.length + r2.length + r3.length + r4.length
  }

  def check_range3: Int = {
    def trues(xs: List[Boolean]) = xs.foldLeft(0)((a, b) => if (b) a+1 else a)
    val r1 = Iterator.range(0, 10)
    val xs1 = List(r1 contains 5, r1 contains 6)
    val r2 = Iterator.range(0, 10, 2)
    val xs2 = List(r2 contains 5, r2 contains 6)
    val r3 = Iterator.range(0, 10, 11)
    val xs3 = List(r3 contains 5, r3 contains 6)
    // 2 + 1 + 0
    trues(xs1) + trues(xs2) + trues(xs3)
  }

  def check_take: Int = {
    val it1 = Iterator.from(0)
    val xs1 = it1 take 10 toList;
    xs1.length
  }

  def check_drop: Int = {
    val it1 = Iterator.from(0)
    val it2 = it1 map { 2 * _ }
    val n1 = it1 drop 2 next
    val n2 = it2 drop 2 next;
    n1 + n2
  }

  def check_foreach: Int = {
    val it1 = Iterator.from(0) take 20
    var n = 0
    it1 foreach { n += _ }
    n
  }

  def check_forall: Int = {
    val it1 = Iterator.from(0)
    val it2 = Iterator.from(1)
    0
  }

  def check_success[A](name: String, closure: => A, expected: A): Unit = {
    Console.print("test " + name)
    try {
      val actual: A = closure
      if (actual == expected)
        Console.print(" was successful")
      else
        Console.print(" failed: expected "+ expected +", found "+ actual)
    }
    catch {
      case exception: Throwable =>
        Console.print(" raised exception " + exception)
    }
    Console.println
  }

  def main(args: Array[String]) {
    check_success("check_from",     check_from,     -1)
    check_success("check_range",    check_range,    11)
    check_success("check_range2",   check_range2,   26)
    check_success("check_range3",   check_range3,    3)
    check_success("check_take",     check_take,     10)
    check_success("check_drop",     check_drop,     12)
    check_success("check_foreach",  check_foreach, 190)
    check_success("check_forall",   check_forall,    0)
    Console.println
  }
}

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