Here's a small example of how to extends types by giving them more operations in Scala.

DSL.scala

object DSL {
  implicit def MkDSLRichAnyOps[T](elem: T) = 
    new DSLRichAny(elem)
}

DSLRichAny.scala

class DSLRichAny[T](elem: T) {
  def elemOf(that: Set[T]) = that contains elem
}

DSLTestApp.scala

object DSLTestApp extends DSL {
  def main(args: Array[String]): Unit = {
    val set1 = Set(1, 2, 3, 4)
    val set2 = Set("a", "b", "c", "d")
    println(2 elemOf set1) // should print true
    println(5 elemOf set1) // should print false
    println("a" elemOf set2) // should print true
    // println(1 elemOf set2) // won't compile; type mismatch!
  }
}

gistfile4.txt

These code snippets were used as examples in a blog post titled 
"Implicit additions to types for DSL’s (Scala)." This post can be 
found here at http://michaelcotterell.com/