Scala 2.9.0.final Changesの確認

gistfile1.scala

// ----------------------
// Scala 2.9.0.final
// http://www.scala-lang.org/node/43

// ----------------------
// REPLのexitはdeprecated

scala> exit
<console>:8: warning: method exit in object Predef is deprecated: Use sys.exit() instead
       exit
       ^

// ----------------------
// Parallel Collections
// - bulkっぽい処理をやるやつ。

// これまでのコレクション型
Range(0,100,1) foreach { i => print(i+",") }
// 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,
// 31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,
// 61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,
// 91,92,93,94,95,96,97,98,99,

// 従来のコレクション型にparメソッドが追加された
Range(0,100,1).par foreach { i => print(i+",") }
// 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,
// 31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,75,76,77,78,79,80,81,82,83,84,85,
// 86,87,88,89,90,91,92,93,94,95,96,97,98,99,62,63,64,65,66,67,68,69,70,71,72,73,74,56,57,58,
// 59,60,61,50,51,52,53,54,55,

// parallelパッケージ
import collection.parallel.immutable._
ParRange(0,100,1,false) foreach { i => print(i+",") } 
// 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,
// 31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,75,76,77,78,79,80,81,82,83,84,85,
// 86,87,88,89,90,91,92,93,94,95,96,97,98,99,62,63,64,65,66,67,68,69,70,71,72,73,74,56,57,58,
// 59,60,61,50,51,52,53,54,55,

// スレッドID出力してみた
scala> Range(0,20,1).par foreach { i => print(Thread.currentThread.getId+",") }
20,20,20,20,20,20,20,20,20,20,19,19,19,19,19,21,21,21,21,21,
scala> Range(0,20,1).par foreach { i => print(Thread.currentThread.getId+",") }
20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,
scala> Range(0,20,1).par foreach { i => print(Thread.currentThread.getId+",") }
21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,
scala> Range(0,20,1).par foreach { i => print(Thread.currentThread.getId+",") }
20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,21,21,
scala> 

// ------------------------
// Application traitがdeprecatedに -> 新しいApp trait使う
// ※Application traitはスレッドセーフでなかったため

scala> class Main extends Application {
     |   println("hogehoge")
     | }
<console>:7: warning: trait Application is deprecated: use App instead
       class Main extends Application {
                          ^
defined class Main

scala> class Main extends App {
     |   println("hogehoge")
     | }
defined class Main

// ------------------------
// DelayedInit trait
// - インスタンス化のタイミングで呼ばれる、という認識でよいのだろうか・・

object Status extends Enumeration {
  val Todo = Value("Todo")
  val Doing = Value("Doing")
  val Done = Value("Done")
}
class CurrentStatus extends DelayedInit {
  var status: Option[Status.Value] = None
  override def delayedInit(x: => Unit): Unit = {
    println("delayed init...")
    status = Some(Status.Todo)
  }
}
val current = new CurrentStatus // delayed init...

// ------------------------
// Repl Improvements

scala> :imports
 1) import java.lang._             (153 types, 158 terms)
 2) import scala._                 (797 types, 805 terms)
 3) import scala.Predef._          (16 types, 167 terms, 96 are implicit)

scala> :implicits
No implicits have been imported other than those in Predef.

scala> :keybindings
Reading jline properties for default key bindings.
Accuracy not guaranteed: treat this as a guideline only.

  1 CTRL-A: move to the beginning of the line
  2 CTRL-B: move to the previous character
  4 CTRL-D: close out the input stream
....

scala> case class Sample(val name: String)
defined class Sample

scala> :javap Sample
Compiled from "<console>"
public class Sample extends java.lang.Object implements scala.ScalaObject,scala.Product,scala.Serializable{
    public scala.collection.Iterator productIterator();
    public scala.collection.Iterator productElements();
    public java.lang.String name();
    public Sample copy(java.lang.String);
    public java.lang.String copy$default$1();
    public int hashCode();
    public java.lang.String toString();
    public boolean equals(java.lang.Object);
    public java.lang.String productPrefix();
    public int productArity();
    public java.lang.Object productElement(int);
    public boolean canEqual(java.lang.Object);
    public Sample(java.lang.String);
}

// ------------------------
// Scala Runner
// - scala -saveでjarファイルがつくられたりする

$ cat sample.scala 
case class Name(val first:String, val last:String)
val name = Name("Kazuhiro", "Sera")
println(name)
$ scala -save sample.scala
Name(Kazuhiro,Sera)
$ ls
sample.jar	sample.scala
$ scala sample.jar
Name(Kazuhiro,Sera)
$

// ------------------------
// Generalized try-catch-finally:

val handler: PartialFunction[Throwable,Unit] = {
  case t @ (_: RuntimeException) => t.printStackTrace
}
val cleanup = () => println("finally")

def main() {
  try throw new RuntimeException
  catch handler
  finally cleanup()
}
main
/*
scala> main
java.lang.RuntimeException
	at $line66.$read$$iw$$iw$$iw$$iw$.main(<console>:14)
	at $line67.$read$$iw$$iw$$iw$$iw$.<init>(<console>:15)
	at $line67.$read$$iw$$iw$$iw$$iw$.<clinit>(<console>)
	at $line67.$eval$.<init>(<console>:11)
	at $line67.$eval$.<clinit>(<console>)
	at $line67.$eval.$export(<console>)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at scala.tools.nsc.interpreter.IMain$ReadEvalPrint.call(IMain.scala:592)
	at scala.tools.nsc.interpreter.IMain$Request$$anonfun$10.apply(IMain.scala:828)
	at scala.tools.nsc.interpreter.Line$$anonfun$1.apply$mcV$sp(Line.scala:43)
	at scala.tools.nsc.io.package$$anon$2.run(package.scala:31)
	at java.lang.Thread.run(Thread.java:680)
finally
*/

// ------------------------
// scala.sys and scala.sys.process, which are imported from sbt.Process.

http://code.google.com/p/simple-build-tool/wiki/Process