Scala example source code file (structural.scala)

This example Scala source code file (structural.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, b, c, d, d, e, null, null, object, object, t, tata, tata, unit

The Scala structural.scala source code

object Test extends App {
  
  def f(x: { type D; def m: D }): Null = null
    
  class Tata
  
  abstract class Toto[A <: Object] {
    type B <: Object
    
    def f1[C <: Object](x: Object{ type D <: Object; def m[E >: Null <: Object](x: A): Object; val x: A }) = x.m[Tata](x.x) //fail
    def f2[C <: Object](x: Object{ type D <: Object; def m[E >: Null <: Object](x: B): Object; val x: B }) = x.m[Tata](x.x) //fail
    def f3[C <: Object](x: Object{ type D <: Object; def m[E >: Null <: Object](x: C): Object; val x: C }) = x.m[Tata](x.x) //fail
    def f4[C <: Object](x: Object{ type D <: Object; def m[E >: Null <: Object](x: D): Object; val x: D }) = x.m[Tata](x.x) //fail
    def f5[C <: Object](x: Object{ type D <: Object; def m[E >: Null <: Object](x: E): Object; val x: Tata }) = x.m[Tata](x.x) //suceed
    
    def f6[C <: Object](x: Object{ type D <: Object; def m[E >: Null <: Object](x: Object): A }) = x.m[Tata](null) //suceed
    def f7[C <: Object](x: Object{ type D <: Object; def m[E >: Null <: Object](x: Object): B }) = x.m[Tata](null) //suceed
    def f8[C <: Object](x: Object{ type D <: Object; def m[E >: Null <: Object](x: Object): C }) = x.m[Tata](null) //suceed
    def f9[C <: Object](x: Object{ type D <: Object; def m[E >: Null <: Object](x: Object): D }) = x.m[Tata](null) //fail
    def f0[C <: Object](x: Object{ type D <: Object; def m[E >: Null <: Object](x: Object): E }) = x.m[Tata](null) //suceed
    
  }
  
  val tata = new Tata
  val toto = new Toto[Tata] {
    type B = Tata
  }
  
  //toto.f1[Tata](new Object{ type D = Tata; def m[E >: Null <: Object](x: Tata): Object = null; val x = tata })
  //toto.f2[Tata](new Object{ type D = Tata; def m[E >: Null <: Object](x: Tata): Object = null; val x = tata })
  //toto.f3[Tata](new Object{ type D = Tata; def m[E >: Null <: Object](x: Tata): Object = null; val x = tata })
  //toto.f4[Tata](new Object{ type D = Tata; def m[E >: Null <: Object](x: D): Object = null; val x = tata })
  toto.f5[Tata](new Object{ type D = Tata; def m[E >: Null <: Object](x: E): Object = null; val x: Test.Tata = tata })
  
  toto.f6[Tata](new Object{ type D = Tata; def m[E >: Null <: Object](x: Object): Tata = null })
  toto.f7[Tata](new Object{ type D = Tata; def m[E >: Null <: Object](x: Object): Tata = null })
  toto.f8[Tata](new Object{ type D = Tata; def m[E >: Null <: Object](x: Object): Tata = null })
  //toto.f9[Tata](new Object{ type D = Tata; def m[E >: Null <: Object](x: Object): D = null })
  toto.f0[Tata](new Object{ type D = Tata; def m[E >: Null <: Object](x: Object): E = null })
  
  /* Bug #1246 */
  type Summable[T] = { def +(v : T) : T }
  def sum[T <: Summable[T]](xs : List[T]) = xs.reduceLeft[T](_ + _)
  
  /* Bug #1004 & #967 */
  type S1 = { def f(p: this.type): Unit }
  val s1 = new { def f(p: this.type): Unit = () }
  
  type S2 = { type T; def f(p: T): Unit }
  //val s2: S2 = new { type T = A; def f(p: T): Unit = () }
  
  def s3[U >: Null <: Object](p: { def f(p: U): Unit; def u: U }) = ()
  
}