Private and protected constructor in Scala

Question

I\'ve been curious about the impact of not having an explicit primary constructor in Scala, just the contents of the class body.

In particular, I suspect that the pr

Answer 1

Aleksander's answer is correct, but Programming in Scala offers an additional alternative:

sealed trait Foo {
 // interface
}

object Foo {
  def apply(...): Foo = // public constructor

  private class FooImpl(...) extends Foo { ... } // real class
}