This program is being written for an upcoming ElixirDose.com article.
In it, we will seek to discover if the shuffle function mixes up an array better if it's run more than once.
There's a mix dependence in here for Elixir 12.3-dev. You might want to change that if you're not running the most up-to-date version of Elixir and Erlang.
UPDATE: January 21, 2014 This code is generally complete. I run it by jumping into iex and running ShuffleStep.run(x), where x is the number of shuffles you want to give the deck.
TO DO: My biggest hope is to turn this into a massive computation problem and run it with some parallel processing. Spawn sessions, pass pids, the whole lot. That's the next step and the next tutorial. I hope. Chapter 13 of Dave Thomas' book is still bending my mind into the proper shape for that.
This is the final Elixir Dose article.
Here is the multi-process version of this code. (Still a work in progress...)