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// test "val foo =" clauses in for comprehensions
// $Id$
import scala.collection.immutable.Queue
import scala.{List=>L}
object Test {
// redefine some symbols to make it extra hard
class List
class Tuple2
def List[A](as:A*) = 5
def firstDigit(x:int): int =
x match {
case 0 => 0
case _ if(x<0) => firstDigit(-x)
case _ if(x<10) => x
case _ => firstDigit(x / 10)
}
{
// a basic test case
val input = L.range(0,20)
val oddFirstTimesTwo =
for{val x <- input
val xf = firstDigit(x)
xf % 2 == 1}
yield x*2
Console.println(oddFirstTimesTwo)
}
{
// a test case with patterns
val input = L.range(0,20)
val oddFirstTimesTwo =
for{val x <- input
val xf = firstDigit(x)
val yf = x - firstDigit(x) / 10
val Pair(a, b) = Pair(xf - yf, xf + yf)
xf % 2 == 1}
yield a + b
Console.println(oddFirstTimesTwo)
}
{
// make sure it works on non-Ls
// val input: Queue = Queue.Empty[int].incl(L.range(0,20))
val input = L.range(0,20).elements
val oddFirstTimesTwo =
for{val x <- input
val xf = firstDigit(x)
xf % 2 == 1}
yield x*2
Console.println(oddFirstTimesTwo.toList)
}
{
// yield the computed value
val input = L.range(0,20)
val oddFirstTimesTwo =
for{val x <- input
val xf = firstDigit(x)
xf % 2 == 1}
yield xf*2
Console.println(oddFirstTimesTwo)
}
{
// make sure the function is only called once
var count: int = 0
def fdct(x: int) = {
count = count + 1
firstDigit(x)
}
val input = L.range(0,20)
for{val x <- input
val xf = fdct(x)
xf % 2 == 1}
yield xf
Console.println("called " + count + " times")
}
def main(args: Array[String]): Unit = ()
}
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