My first Rust program

fib.rs

// My first Rust program
// Simply outputs fibbonaci numbers from 20 to 0

use core::task::spawn;

fn fib(number: int) -> int {
    if number > 1 {
      return fib(number - 1) + fib(number - 2);
    } else {
      return number;
    }
}

fn main() {
    for int::range(0, 20) |num| {
        do spawn {
           io::println(fmt!("Fibbonaci of %d is: %d\n", num, fib(num)));
        }
    }
}