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class C[T](x: T) { override def toString(): String = x.toString(); }
object TestPolymorphicClasses {
def main(args: Array[String]): Unit = {
Console.println("===== polymorphic classes");
Console.println(new C("true"));
Console.println(new C(true));
Console.println((new C("a")).isInstanceOf[C[String]]);
Console.println(!(new C(42)).isInstanceOf[C[String]]);
}
}
class Outer {
class Inner;
}
class SubOuter extends Outer {
class SubInner extends Inner;
}
object TestNestedClasses {
def main(args: Array[String]): Unit = {
Console.println("===== nested classes");
val o1 = new Outer;
val i1 = new o1.Inner;
val o2 = new Outer;
val i2 = new o2.Inner;
Console.println( i1.isInstanceOf[o1.Inner]);
Console.println( i2.isInstanceOf[o2.Inner]);
Console.println(!i1.isInstanceOf[o2.Inner]);
Console.println(!i2.isInstanceOf[o1.Inner]);
val so1 = new SubOuter;
val si1 = new so1.SubInner;
val i3 = new so1.Inner;
Console.println( si1.isInstanceOf[so1.Inner]);
Console.println(!si1.isInstanceOf[o1.Inner]);
Console.println(! i3.isInstanceOf[so1.SubInner]);
// Console.println( i3.isInstanceOf[Outer#SubInner]);
// Console.println( i3.isInstanceOf[Outer#Inner]);
}
}
object TestClassesInsideFunctions {
def f(x: String): ScalaObject = {
class C { override def toString() = x; };
new C
}
def main(args: Array[String]): Unit = {
Console.println("===== classes nested inside functions");
val c1 = f("true");
val c2 = f("true");
Console.println(c1);
Console.println(c2);
Console.println(!c1.getScalaType().isSameType(c2.getScalaType()));
}
}
class Invariant[T];
class Covariant[+T];
class Contravariant[-T];
class MultiVariant[T1, -T2, +T3, T4, -T5, +T6];
object TestVariance {
def main(args: Array[String]): Unit = {
Console.println("===== type paramater variance");
val invO = new Invariant[Object];
val invS = new Invariant[String];
Console.println( invO.isInstanceOf[Invariant[Object]]);
Console.println(!invO.isInstanceOf[Invariant[String]]);
Console.println(!invS.isInstanceOf[Invariant[Object]]);
Console.println( invS.isInstanceOf[Invariant[String]]);
val covO = new Covariant[Object];
val covS = new Covariant[String];
Console.println( covO.isInstanceOf[Covariant[Object]]);
Console.println(!covO.isInstanceOf[Covariant[String]]);
Console.println( covS.isInstanceOf[Covariant[Object]]);
Console.println( covS.isInstanceOf[Covariant[String]]);
val conO = new Contravariant[Object];
val conS = new Contravariant[String];
Console.println( conO.isInstanceOf[Contravariant[Object]]);
Console.println( conO.isInstanceOf[Contravariant[String]]);
Console.println(!conS.isInstanceOf[Contravariant[Object]]);
Console.println( conS.isInstanceOf[Contravariant[String]]);
val mulO = new MultiVariant[Object,Object,Object,Object,Object,Object];
val mulS = new MultiVariant[String,String,String,String,String,String];
Console.println( mulO.isInstanceOf[MultiVariant[Object,Object,Object,Object,Object,Object]]);
Console.println( mulO.isInstanceOf[MultiVariant[Object,String,Object,Object,String,Object]]);
Console.println( mulS.isInstanceOf[MultiVariant[String,String,String,String,String,String]]);
Console.println(!mulS.isInstanceOf[MultiVariant[Object,Object,Object,Object,Object,Object]]);
Console.println( mulS.isInstanceOf[MultiVariant[String,String,Object,String,String,Object]]);
}
}
object TestSingletonTypes {
def main(args: Array[String]): Unit = {
Console.println("===== singleton types");
val x: String = "x";
val y: String = "y";
Console.println( x.isInstanceOf[x.type]);
Console.println(!x.isInstanceOf[y.type]);
}
}
object TestCompoundTypes {
class C, D;
def main(args: Array[String]): Unit = {
Console.println("===== compound types");
val c = new C;
val d = new D;
Console.println(!c.isInstanceOf[C with D]);
Console.println(!c.isInstanceOf[D with C]);
Console.println(!d.isInstanceOf[C with D]);
Console.println(!d.isInstanceOf[D with C]);
val cd = new C with D;
val dc = new D with C;
Console.println(cd.isInstanceOf[C]);
Console.println(cd.isInstanceOf[D]);
Console.println(cd.isInstanceOf[C with D]);
Console.println(cd.isInstanceOf[D with C]);
Console.println(dc.isInstanceOf[C]);
Console.println(dc.isInstanceOf[D]);
Console.println(dc.isInstanceOf[C with D]);
Console.println(dc.isInstanceOf[D with C]);
}
}
object TestNull {
class C;
def main(args: Array[String]): Unit = {
Console.println("===== null");
Console.println(!null.isInstanceOf[Any]);
Console.println(!null.isInstanceOf[AnyRef]);
Console.println(!null.isInstanceOf[AllRef]);
Console.println(!null.isInstanceOf[C]);
Console.println((null.asInstanceOf[AnyRef]) == null);
try {
Console.println(null.asInstanceOf[Any]);
Console.println("false (THIS SHOULD NOT BE PRINTED!!!)");
} catch {
case _: ClassCastException => ()
}
}
}
object TestDefaultValue {
def defaultValue[T]: T = {
class Cell[T] { var x: T = _; }
return (new Cell[T]).x;
}
class C;
def main(args: Array[String]): Unit = {
Console.println("===== default value");
Console.println(defaultValue[Boolean] == false);
Console.println(defaultValue[Byte] == 0.asInstanceOf[Byte]);
Console.println(defaultValue[Short] == 0.asInstanceOf[Short]);
Console.println(defaultValue[Int] == 0);
Console.println(defaultValue[Long] == 0.asInstanceOf[Long]);
Console.println(defaultValue[Float] == 0.asInstanceOf[Float]);
Console.println(defaultValue[Double] == 0.asInstanceOf[Double]);
Console.println(defaultValue[String] == null);
Console.println(defaultValue[C] == null);
}
}
object TestArrays {
def isInst[T](x: Any): Boolean = x.isInstanceOf[T];
def main(args: Array[String]): Unit = {
Console.println("===== arrays");
import java.lang.reflect.{Array => JArray};
val iArray = JArray.newInstance(Integer.TYPE, 5);
Console.println(iArray.isInstanceOf[Array[Int]]);
Console.println(isInst[Array[Int]](iArray));
val oArray = JArray.newInstance(Class.forName("java.lang.Object"), 5);
Console.println(oArray.isInstanceOf[Array[Object]]);
Console.println(isInst[Array[Object]](oArray));
}
}
object Test {
def main(args: Array[String]): Unit = {
TestPolymorphicClasses.main(args);
TestNestedClasses.main(args);
TestClassesInsideFunctions.main(args);
TestVariance.main(args);
TestSingletonTypes.main(args);
TestCompoundTypes.main(args);
TestNull.main(args);
TestDefaultValue.main(args);
TestArrays.main(args);
}
}
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