for式はforeach

.for-expression_is_foreach.md

for式はforeach

build.sbt

lazy val root = (project in file(".")).settings(
  scalaVersion := "2.11.5",
  scalacOptions += "-Xprint:typer"
)

sample1.scala

package sample1

object Main extends App {
  
  val seq = Seq(1, 2, 3)
  
  for (i <- seq) println(i)
  
}

sample1_print_typer.scala

[[syntax trees at end of                     typer]] // sample1.scala
package sample1 {
  object Main extends AnyRef with App {
    def <init>(): sample1.Main.type = {
      Main.super.<init>();
      ()
    };
    private[this] val seq: Seq[Int] = collection.this.Seq.apply[Int](1, 2, 3);
    <stable> <accessor> def seq: Seq[Int] = Main.this.seq;
    Main.this.seq.foreach[Unit](((i: Int) => scala.this.Predef.println(i)))
  }
}

sample2.scala

package sample2

object Main extends App {
  
  object Eachable {
    import scala.util.Random
    
    private val random = new Random
    
    // ランダムな数値を引数に３回呼び出す。
    def foreach(f: (Int) => Unit) = {
      f(random.nextInt)
      f(random.nextInt)
      f(random.nextInt)
    }
  }
  
  for (i <- Eachable) println(i)
  
}

sample2_print_typer.scala

[[syntax trees at end of                     typer]] // sample2.scala
package sample2 {
  object Main extends AnyRef with App {
    def <init>(): sample2.Main.type = {
      Main.super.<init>();
      ()
    };
    object Eachable extends scala.AnyRef {
      def <init>(): sample2.Main.Eachable.type = {
        Eachable.super.<init>();
        ()
      };
      import scala.util.Random;
      private[this] val random: scala.util.Random = new scala.util.Random();
      <stable> <accessor> private def random: scala.util.Random = Eachable.this.random;
      def foreach(f: Int => Unit): Unit = {
        f.apply(Eachable.this.random.nextInt());
        f.apply(Eachable.this.random.nextInt());
        f.apply(Eachable.this.random.nextInt())
      }
    };
    Main.this.Eachable.foreach(((i: Int) => scala.this.Predef.println(i)))
  }
}