在Scala中可以嵌套定义方法。例如以下对象提供了一个factorial方法来计算给定数值的阶乘：

 def factorial(x: Int): Int = {
    def fact(x: Int, accumulator: Int): Int = {
      if (x <= 1) accumulator
      else fact(x - 1, x * accumulator)
    }  
    fact(x, 1)
 }
 println("Factorial of 2: " + factorial(2))
 println("Factorial of 3: " + factorial(3))

程序的输出为:

Factorial of 2: 2
Factorial of 3: 6