Scala: Fibonacci Revisited and Recursed

Building on the previous Fibonacci number function, we have some more Scala specific tools available at our disposal. In the previous example, I basically did a verbatim duplication of Java to Scala.
This post builds on the same Fibonacci function using the Scala match. match is a Scala implementation of the Java switch statement. Additionally, match is available for all objects instead of just an int, char, byte and short.
Tree Recursion

def fibonacci(num: Int): Int= {
num match {
case 0 => 0
case 1 => 1
case _ => fibonacci(num-1) + fibonacci(num-2)
}
}
This should be relatively straightforward right? One new token that appears in this example is the use of _. The underscore in Scala is a wildcard character and in this case example gives us an 'all others' or 'default' to match. The underscore can also be used in your imports.
Java

import java.io.*;

Scala

import java.io._

Functional languages lend themselves toward recursion rather than looping. Our Fibonacci number method is a recursive function but could make better use of the Scala compiler as tail recursion. Tail recursion will optimize the threads needed for each iteration of our method.
Tail Recursion

def fibonacci(num: Int) = fibonacciTR(num, 1, 0)

def fibonacciTR(num: Int, nxt: Int, res: Int): Int= {
num match {
case 0 => res
case _ => fibonacciTR(num-1, nxt+res, nxt)
}
}

The tail recursion is a good deal more gentle than the tree recursion method. In your journeys toward functional programming put aside what you know about iteration and looping and look at how recursion can do the work for you.