Finite Improbability

Well, finals are officially over, which means I have most of a full week to dedicate to this little hobby of mine. All of the past few posts detail what I’ve accomplished in about two hours or so a night. Now I can spend as much time as I want on this and really get things done.

First things first though, I need to make a decision. I started out working with Scala for this project, and have a decent bit of it done there. The only problem is that I’m not super happy with how the environment works. The Scala compiler takes a long time to run at about six seconds to build a relatively small project. Since I have to drop out of the game to make changes that means I have to:

• Wait for the game to shut down
• Make my changes
• Wait for the project to recompile
• Wait for the game to load
• Make my way back to the point I was testing

So, giving Scala the benefit of the doubt and assuming most of it’s compile time penalty is in JVM startup, let’s estimate a bit. Game shutdown can be really quick, so that’s ~0 seconds. Making changes will happen either way, so that weighs in at ~0 seconds for the comparison. I’ll assume 10 seconds for project compilation (again, giving the benefit). Then it’s another 30 seconds for the game to load and who knows how long to get back to the test point. Since I’m going to have some pretty complex behavior that last one might be a doozy. Either way just the assumed times add up to 40 seconds per iteration to try and fix a bug.

Running the same numbers for Clojure is almost pointless, as I don’t have to shut the game down to make changes. Granted I’ve managed to kill the game a few times by creating a NullPointerException, but every instance that I can remember happened in the render pipeline, which (hopefully) won’t change too much after I really get going.

There are some distinct advantages to Scala though. One of the most obvious ones is that it supports OOP, and thus plays a little better with the game library I am using. So far the bit of playing around I’ve done with Clojure has been in the realm of transferring data from Java to Clojure and back. As I discover new tricks this gets easier, but the majority of my time has been spent in that area. Granted, the little bit of code that I’ve written to actually resemble a game has been pretty powerful, but there you have it.

Another point in Scala’s favor is documentation. I think the community around Scala is a little bigger, and the available documentation reflects this. Clojure has a useful reference in it’s website, and since much of it can be found in the boot.clj file I can always go read the source if I really want to know how something work, but I’m missing a lot of things through simple ignorance. For instance I’ve spent a while accessing elements of a map using ”(get map key)”. Today I learned that maps are functions of their keys so I could have simply called ”(map key)”. Granted the difference is small, but what else is there that I don’t know about?

In the end I think it comes down to me just liking playing with Clojure more than Scala. Scala seems like a pretty solid language, but it’s really hard to pass up the instant satisfaction of the REPL. That and a much slimmer runtime is really nice.