continuations and exceptions

test_exception.scala

// compile with $scalac -P:continuations:enable test_exception.scala
// execute with $scala Test

import scala.util.continuations._

object Test {
    type WithExc[A] = Either[Exception, A]

    def main(args: Array[String]) {
        bar();
    }

    def bar(): Unit = {
        reset {
            try {
                val i: Int = shiftE { (k: Int=>Unit) => foo(k) }
                println("i"+i)
            } catch {
                case e: Exception => println("got exception in bar!")
            }
        }
    }

    def shiftE[A](f: (A=>Unit) => Unit) = {
        val rl: WithExc[A] = shift { wrapper(f) }
        rl match {
            case Left(e)  => throw(e)
            case Right(i) => i
        }
    }

    def wrapper[A](f: (A => Unit) => Unit)(k: WithExc[A] => Unit): Unit = {
        try {
            f(i => k(Right(i)))
        } catch {
            case e:Exception => { println("exception catched in wrapper")
                                  k(Left(e)) }
        }
    }

    def foo(k: Int=>Unit ): Unit = {
        println ("ok cont")
        //throw new Exception("foo")
        k(1)
        println("j")
    }
}