paramodule.scala

// As Daniel said here[http://twitter.com/#!/djspiewak/status/129588554723639296], Scala's traits can be used as 
// polymorphic modules. I was saying the same thing the other day. 
// objects (both regular and the ones declared with 'object' keyword) serve as modules. If you want parametrized
// modules, trait + object combination should be used. A made up example below:

// This is our parametrized module.
trait PhysicsEngine {
  // parameters
  type P <: Planet
  def coeffOfGravity: Double

  // functions, values, classes, type classes, and all other sorts of stuff goes here.
}

// Some concretizations:
object MoonPhysicsEngine extends PhysicsEngine {
  type P = Moon
  def coeffOfGravity = 1.63
}

object EarthPhysicsEngine extends PhysicsEngine {
  type P = Earth
  def coeffOfGravity = 9.8
}

// At use site:
import MoonPhysicsEngine._