Refactoring Scala: My CPU Simulator Revisited

I'm preparing to learn Ruby (though I've already tinkered with it some), and to do so, I'm going to revisit my CPU Simulator project that helped me learn Scala so well. I'm going to write it again in Ruby.

So today, I took up revisiting it, with the goal in mind of writing some Ruby. Turned out that didn't actually happen. What did happen was a lot of refactoring of the original Scala code. I hadn't touched that code in several months, and in between then and now I've written a LOT of Scala. Here's some of the things I've learned (and refactored).

1. I used to use way too much redundant type information. This was a natural habit from writing Java for so long (in fact, pretty much all my bad habits stem from too much Java). I rigorously removed ALL the obviously redundant type declarations. I did find that in some cases it helped to have it there, that the code wasn't exactly clear without it, and so I left it. I'm very interested to see what happens here when I slide over to Ruby.
2. Out of habit, I used a lot of unneeded semi-colons. I removed all of them. I hate semi-colons. It's official.
3. I got a lot better at functional programming. There were a lot of areas where I should have used functions, and I refactored the code to do so. My line of code cound is down considerably.
4. Finally, I removed all the Hamcrest matchers. This one I'll explain in more detail in my post tomorrow. I'm basically using my own assert library that allows me to say things like: x mustBe 5 I prefer this style to any other assertions I've come across.