Ruby'ish Scala

rubylike_scala.scala

class Op[A]
case class EachOp[A]() extends Op[A]
case class CollectOp[A]() extends Op[A]

case class RubyIterator[B, A](iter: Iterator[A], op: Op[B]) {
  def `do`(f: A => B): List[B] = {
    op match {
      case EachOp() =>
        iter.foreach(f)
        List.empty[B]
      case CollectOp() =>
        iter.map(f).toList
    }
  }
}

case class Foo[A](items: List[A]) {
  def each() = {
    mkIterator(EachOp[Unit]())
  }

  def collect() = {
    mkIterator(CollectOp[A]())
  }

  private def mkIterator[B](op: Op[B]) = {
    RubyIterator[B, A](items.iterator, op)
  }
}

object main {
  def main(args: Array[String]): Unit = {
    val f = Foo(List(1,2,3))

    // Ruby-like syntax
    println("Each:")
    f.each `do` { num =>
      println(num)
    }

    println("")
    println("Collect:")
    val doubled = f.collect `do` { num: Int =>
      num * 2
    }

    Foo(doubled).each `do` { num =>
      println(num)
    }
  }
}


//Each:
//1
//2
//3
//
//Collect:
//2
//4
//6