unapplycomplex.scala

来自「JAVA 语言的函数式编程扩展」· SCALA 代码 · 共 38 行

trait Complex extends Product2[double,double]

class ComplexRect(val _1:double, val _2:double) extends Complex {
  override def toString = "ComplexRect("+_1+","+_2+")"
}

class ComplexPolar(val _1:double, val _2:double) extends Complex {
  override def toString = "ComplexPolar("+_1+","+_2+")"
}

object ComplexRect {
  def unapply(z:Complex): Option[Complex] = {
    if(z.isInstanceOf[ComplexRect]) Some(z) else z match {
      case ComplexPolar(mod, arg) =>
	Some(new ComplexRect(mod*Math.cos(arg), mod*Math.sin(arg)))
} } }

object ComplexPolar {
  def unapply(z:Complex): Option[Complex] = {
    if(z.isInstanceOf[ComplexPolar]) Some(z) else z match {
      case ComplexRect(re,im) =>
	Some(new ComplexPolar(Math.sqrt(re*re + im*im), Math.atan(re/im)))
} } }

object Test {
  def main(args:Array[String]) = {
    new ComplexRect(1,1) match {
      case ComplexPolar(mod,arg) => // z @ ???
	Console.println("mod"+mod+"arg"+arg)
    }
    val Komplex = ComplexRect
    new ComplexPolar(Math.sqrt(2),Math.Pi / 4.0) match {
      case Komplex(re,im) => // z @ ???
	Console.println("re"+re+" im"+im)
    }
  }
}