Case object extending trait

Question

We can supply parameter to a class extending trait with the same name as an abstract method like

trait Trr{
   def m: String
}

case class Trrrr(m: String) extends Trr  //fine

This example compiles fine. But I tried to do something like that with case objects and failed:

trait Command{
  def name: String
}

case object Unload("unld") extends Command //compile error

Is there a way to write this concisely while leaving Command a trait, not an abstract class with parameter? I mean not like that:

case object Unload extends Command {
  override def name: String = "unld"
}

or

abstract class Command(name: String)

case object Unload extends Command("unld")

OlivierBlanvillain · Accepted Answer · 2017-06-22 13:20:27Z

3

case object Unload extends Command { val name = "unld" }

Object don't have arguments, things won't get any shorted than the above...

answered Jun 22, 2017 at 13:20

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Comments

Gilad Cohen · Accepted Answer · 2017-06-22 13:31:13Z

1

You can instantiate the trait directly like so:

val newTrr = new Trr { val m = "example" }

At this point you can use the newTrr value just like any class instance...

println(newTrr.m)

which will print out: "example".

answered Jun 22, 2017 at 13:31

Gilad Cohen

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