gistfile1.scala

type Greeting = () => String

def greet(g: Greeting) = {
  println(g())
}

def hello() = { "hello from Huey" }

greet(hello) // >> "hello from Huey"

type Greeter = { def greet() }

def greet(g: Greeter) = {
  g.greet()
}

object Hello {
  def greet() = { println "hello, again, from Huey" }
}

greet(Hello) // >> "hello, again, from Huey"