在Scala中是可以定义嵌套函数的。下面定义了函数factorial，用于计算给定数字的阶乘：
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))
程序输出结果是：
Factorial of 2: 2
Factorial of 3: 6