TaskTest.scala

import sbt._
import std._

class TaskTest extends SingleProject
{
  lazy val hello: Task[Unit] =
    task { println("Hi!") }

  lazy val three: Task[Int] =
    task { 3 }

  lazy val goodbye: Task[Unit] = task { println("Goodbye") } dependsOn(hello)

  lazy val four: Task[Int] = three map { (t: Int) => t + 1 }

   lazy val rand: Task[Boolean] = task { math.random > 0.5 }
   lazy val num: Task[Int] = rand flatMap { (b: Boolean) => if(b) four else three }

  lazy val par: Task[Int] = (three, four) map { (t: Int, f: Int) => t * f }

  lazy val forkReduce: Task[Int] = (0 to 1000).fork( _ * 3).reduce { _ + _ }
  lazy val forkJoin: Task[Seq[Int]] = (0 to 1000).fork(_ * 3).join

  lazy val fail: Task[Int] = task { error("A failure.") }
  lazy val catchLike: Task[Unit] = fail mapFailure { (t: Incomplete) => t.printStackTrace }

  lazy val alwaysRunA: Task[Int] = fail andFinally { println("Finally 1") }
  lazy val alwaysRunB: Task[Int] = four andFinally { println("Finally 2") }

  // succeeds because 'hello' succeeds.  The result is that of the final task, which is `three` here.
  lazy val allA: Task[Int] = hello && three

  // fails because 'fail' fails
  lazy val allB: Task[Unit] = fail && hello

  lazy val orA: Task[Int] = fail || four
  lazy val orB: Task[Int] = four || fail
  lazy val orC: Task[Int] = four || three

  lazy val fullA: Task[Int] = four mapR {
    case Inc(i) => 0
    case Value(v) => v
  }

  val ScalaVersion = AttributeKey[String]("scala-version")
  val Number = AttributeKey[Int]("num")

  lazy val scalaVersion: Task[String] = cross(ScalaVersion)("2.7.7", "2.8.0")
  lazy val number: Task[Int] = cross(Number)(1,2,3)

  lazy val printVersion: Task[Unit] = scalaVersion map println
  lazy val printNumber: Task[Unit] = number map println

  lazy val printBoth: Task[Unit] = (scalaVersion, number) map { (v: String, n: Int) => println(n + ": " + v) }

  lazy val numA: Task[Int] = cross(Number)(1,2,3)
  lazy val numB: Task[Int] = cross(Number)(4,5,6)
  //lazy val numC = (numA, numB) map { (a: Int, b: Int) => a * b }

  lazy val stringBoth: Task[String] = (scalaVersion, number) map { (v: String, n: Int) => n + ": " + v }
  lazy val merged: Task[Seq[(AttributeMap, String)]] = stringBoth.merge
}