exampleExtensionMethod.scala

def substract(i:Int)=extension{
  //owner represents the object you are extending 
  owner:Int =>
     {
       owner-i
     }
}

//operator tild ~ instead of . for extensions
1~substract(2)~substract(1)~substract(1)

extensionMethods.scala

//implementation of extension methods in scala:
object ExtensionFunctions{
 case class ExtensionFunction[A,R](f:Function[A,R]) extends Function[A,R]{override def apply(a:A)=f(a)}
 def extension[A,R](f:A=>R)=ExtensionFunction(f)
 implicit def anythingIsExtensible[A](a:A):ExtensionsOn[A]= ExtensionsOn(a)
 case class ExtensionsOn[A](a:A){
  //adding this generic operator on type Any would ?remove? the overhead of doing implicit conversions here
  def ~[R] (f:ExtensionFunction[A,R]):R = f(a)
 }
}