Practical uses of a Dynamic type in Scala

Question

Besides integration with dynamic languages on the JVM, what are the other powerful uses of a Dynamic type in a statically typed language like Scala?

Answer 1

You might also use it for syntactic sugar on maps:

class DynamicMap[K, V] extends Dynamic {
  val self = scala.collection.mutable.Map[K, V]()
  def _select_(key: String) = self.apply(key)
  def _invoke_(key: String)(value: Any*) = 
    if (value.nonEmpty) self.update(key, value(0).asInstanceOf[V])
    else throw new IllegalArgumentException
}

val map = new DynamicMap[String, String]()

map.foo("bar")  // adds key "foo" with value "bar"    
map.foo         // returns "bar"

To be honest this only saves you a couple of keystrokes from:

val map = new Map[String, String]()
map("foo") = "bar"
map("foo")