How to create a singleton object in Scala with runtime params

Singletons are initialized lazily.

scala> :pa
// Entering paste mode (ctrl-D to finish)

object Net {
  val address = Config.address
}
object Config { var address = 0L }

// Exiting paste mode, now interpreting.

defined object Net
defined object Config

scala> Config.address = "1234".toLong
Config.address: Long = 1234

scala> Net.address
res0: Long = 1234

FWIW.