echo.scala

def echoWhatYouGaveMe(x: Any): String = x match {
  // constant patterns
  case 0 => "zero"
  case true => "true"
  case "hello" => "you said 'hello'"
  case Nil => "an empty List"
  // sequence patterns
  case List(0, _, _) => "a three-element list with 0 as the first element"
  case List(1, _*) => "a list beginning with 1, having any number of elements"
  case Vector(1, _*) => "a vector starting with 1, having any number of elements"
  // tuples
  case (a, b) => s"got $a and $b"
  case (a, b, c) => s"got $a, $b, and $c"
  // constructor patterns
  case Person(first, "Alexander") => s"found an Alexander, first name = $first"
  case Dog("Suka") => "found a dog named Suka"
  // typed patterns
  case s: String => s"you gave me this string: $s"
  case i: Int => s"thanks for the int: $i"
  case f: Float => s"thanks for the float: $f"
  case a: Array[Int] => s"an array of int: ${a.mkString(",")}"
  case as: Array[String] => s"an array of strings: ${as.mkString(",")}"
  case d: Dog => s"dog: ${d.name}"
  case list: List[_] => s"thanks for the List: $list"
  case m: Map[_, _] => m.toString
  // the default wildcard pattern
  case _ => "Unknown"
}

case class Person(firstName: String, lastName: String)
case class Dog(name: String)
// trigger the constant patterns
println(echoWhatYouGaveMe(0))
println(echoWhatYouGaveMe(true))
println(echoWhatYouGaveMe("hello"))
println(echoWhatYouGaveMe(Nil))
// trigger the sequence patterns
println(echoWhatYouGaveMe(List(0,1,2)))
println(echoWhatYouGaveMe(List(1,2)))
println(echoWhatYouGaveMe(List(1,2,3)))
println(echoWhatYouGaveMe(Vector(1,2,3)))// trigger the tuple patterns
println(echoWhatYouGaveMe((1,2))) // two element tuple
println(echoWhatYouGaveMe((1,2,3))) // three element tuple
                                    // trigger the constructor patterns
println(echoWhatYouGaveMe(Person("Melissa", "Alexander")))
println(echoWhatYouGaveMe(Dog("Suka")))
// trigger the typed patterns
println(echoWhatYouGaveMe("Hello, world"))
println(echoWhatYouGaveMe(42))
println(echoWhatYouGaveMe(42F))
println(echoWhatYouGaveMe(Array(1,2,3)))
println(echoWhatYouGaveMe(Array("coffee", "apple pie")))
println(echoWhatYouGaveMe(Dog("Fido")))
println(echoWhatYouGaveMe(List("apple", "banana")))
println(echoWhatYouGaveMe(Map(1->"Al", 2->"Alexander")))
// trigger the wildcard pattern
println(echoWhatYouGaveMe("33d"))