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//############################################################################
// Iterators
//############################################################################
// $Id$
//############################################################################
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 xs2 = List(r2 contains 5, r2 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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