Demonstrate how to dynamically add variables to an object (a class instance) at runtime.

This is useful when the methods/variables of an instance are based on a data file that isn't available until runtime. Hal Fulton gives an example of creating an OO CSV parser at An Exercise in Metaprogramming with Ruby. This is referred to as "monkeypatching" by Pythonistas and some others.

import language.dynamics
import scala.collection.mutable.HashMap
 
class A extends Dynamic {
  private val map = new HashMap[String, Any]
  def selectDynamic(name: String): Any = {
    return map(name)
  }
  def updateDynamic(name:String)(value: Any) = {
    map(name) = value
  }
}