类和伴随对象如何在Scala中看到私有val？

Question

object Foo {
  private val thing: String = "Yay"
}

case class Foo() {
  println(thing)
}

Is it possible for object Foo's thing to be visible only in class instances of Foo (shared visibility)? As shown, compiler complains

...thing in class is unresolved.

I'd rather not open it up to package-level visibility if it can be avoided.

Answer 1

You need to import members of object Foo inside case class:

object Files {

  object Foo {
    private val thing: String = "Yay"
  }

  case class Foo() {
    import Foo._
    println(thing) //ok
  }
}

Using qualified name Foo.thing without import would also work.