Scala example source code file (misc.scala)

This example Scala source code file (misc.scala) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Scala tags/keywords

a, anyref, anyref, b, bar, exception, hello, int, int, myclass, x, x, y, y

The Scala misc.scala source code

object Test {

  def fac(n: Int): Int = if (n < 2) 1 else fac(n - 1) * n;

  // Fibonacci
  def fib(n: Int): Int = if (n < 2) 1 else fib(n - 1) + fib(n - 2);

  def show_fib(n: Int): Int = {
    Console.print("### fib(");
    Console.print(n);
    Console.print(") = ");
    Console.flush;
    val v = fib(n);
    Console.print(v);
    Console.println;
    Console.flush;
    v
  }

  def id[X](x: X): X = x;

  def apply[X](f: X => X, x: X): X = f(x);

  def id_obj(x: AnyRef): AnyRef = x;

  def apply_obj(f: AnyRef => AnyRef, x: AnyRef): AnyRef = f(x);

  def id_any(x: scala.Any): scala.Any = x;

  def apply_any(f: scala.Any => scala.Any, x: scala.Any): scala.Any = f(x);

  def id_int(x: Int): Int = x;

  def apply_int(f: Int => Int, x: Int): Int = f(x);

  class MyClass() {
    override def toString() = "=== MyClass::toString ===";
    def test() = Console.println("=== MyClass::test ===");
  }

  class MySubclass() extends MyClass() {
    override def toString() = "=== MySubclass::toString ===";
  }

  def foobar = {
    42;
    42l;
    23.5f;
    23.5;
    "Hello";
    32 + 45;
    // !!! System
    // java; // !!! why is this legal ? what  does it return ?
    // java.lang;
    //System.out;
    Console.println("### Hello");
    Console.print("### ");
    Console.println(17);
    Console.println("### Bye");
    Console.println;
    val x = 13;
    x;
    // !!! why are DefDef replaced by Block(Tree[0])? we should use Empty!    
    def f = 19;
    f;
    def f0() = 11;
    f0();
    def f1(x: Int) = x;
    f1(7);
    def f2(x: Int, y: Int) = x + y;
    f2(3,5);
    def f11(x: Int)(y: Int) = x + y;
    f11(23)(2);
    1 < 2;
    if (1 < 2) 3 else 4;


    show_fib(0);
    show_fib(1);
    show_fib(2);
    show_fib(3);
    show_fib(4);

    // !!! show_fib(id[Int](4));

/*
    show_fib(5);
    show_fib(6);
    show_fib(7);
    show_fib(8);
    show_fib(9);
    show_fib(10);
    show_fib(11);
    show_fib(12);
*/

    val myObj = new MyClass();
    Console.println(myObj);
    val mySub = new MySubclass();
    Console.println(mySub);
    myObj.test();
    Console.println;

    Console.println(apply_any(id_any, "identity").toString());
    Console.println;
  };

  foobar;

//############################################################################

class A(a: Int) {
  def getA = a;
}

class B(b: Int, c: Int) extends A(b + c) {
  def getB = b;
}

class X(x: Int) {
  def getX = x;
}
case class Y(y: Int, z: Int) extends X(y + z) {
  def getY = y;
  def getAA = this.y;
}

{
  val a: A = new A(1);
  val b: B = new B(2,3);

  val x: X = new X(4);
  val y: Y = new Y(5,6);

  Console.println("A.a = " + a.getA);
  Console.println("B.a = " + b.getA);
  Console.println("B.b = " + b.getB);
  Console.println;

  Console.println("X.a = " + x.getX);
  Console.println("Y.a = " + y.getX);
  Console.println("Y.b = " + y.getY);
  Console.println("Y.b = " + y.y);
  Console.println;
}

//############################################################################

{
class X() {

  def foo = {
    Console.println("X::foo");
  }

}

class Y() extends X() {

  override def foo = {
    Console.println("Y::foo");
    super.foo;
  }

}

val x: X = new X();
val y: X = new Y();

x.foo;
Console.println;

y.foo;
Console.println;
}

//############################################################################

{
class X() {}

class O(a: Int) {


  case class Y(b: Int) extends X() {
    override def toString() = "";
    def bar = a + b;
  }

  def foo = Y(2).bar
}

Console.println(new O(1).foo)
}

{

class O(a: Int) {

  class X() {}

  case class Y(b: Int) extends X() {
    override def toString() = "";
    def bar = a + b;
  }

  def foo = Y(2).bar
}

Console.println(new O(1).foo)
}

Console.println;

  case class Bar();

  case class Foo(i: Int, j: Char, c: Bar) ;

  Console.println(
    true // Foo(3,'a',Bar()).caseElement( -1 ) == null // throws Exception now
    && Foo(3,'a',Bar()).productElement( 0 ) == 3
    && Foo(3,'a',Bar()).productElement( 1 ) == 'a'
    && Foo(3,'a',Bar()).productElement( 2 ) == Bar()
    && true // Foo(3,'a',Bar()).caseElement( 3 ) == null // throws Exception now
    && Bar().productArity == 0
    && Foo(3,'a',Bar()).productArity == 3);

//############################################################################

  def main(args: Array[String]) {
  }

//############################################################################
}