• Currying, invented by Moses Schönfinkel and Gottlob Frege, is the technique of transforming a Function of Multiple Arguments into a Function of Single Argument

• When a method is called with a fewer number of parameter lists, then this will yield a function taking the missing parameter lists as its arguments

object CurryingTest extends App {

  /*     A method without currying    */
  def sum(x: Int, y: Int) = x + y

  println("Sum : " + sum(1, 2))
  println("Sum : " + sum(1, 3))

  /*     A method using currying    */
  /*     Redefines the sum method so that it takes only a single 'Int' as a parameter and returns a 'Clozure' as a result    */
  /*    Main program calls this 'Clozure', and passes second 'parameter'. This 'Clozure' computes the value and returns the final result    */
  def curriedSum(x: Int) = { (y: Int) => x + y }

  println("CurriedSum: " + curriedSum(1)(2))
  println("CurriedSum: " + curriedSum(1)(3))

  /* Clarification how 'Clozure', returned by 'curriedSum' works */
  val clozure = curriedSum(1)

  println("Clozure: " + clozure(2))
  println("Clozure: " + clozure(3))

  /*     Another improved method using currying    */
  def anotherCurriedSum(x: Int)(y: Int) = x + y

  println("anotherCurriedSum: " + anotherCurriedSum(1)(2))
  println("anotherCurriedSum: " + anotherCurriedSum(1)(3))
}