What is the best JVM Lisp for writing a video game?

Question

This video game won't be super fancy, but the idea is for it to have a moderate amount of functionality. Thoughts?

Edit:

Fast would be nice.

Another edit:

This is what I want:

• To be able to compile everything to .class files that can be packaged into a .jar and run as an application.
• To be able to have working mutable types.
• Have stack traces when there is some sort of error.

I was planning to use Kawa, but I was running into something weird with lists...

Yet another edit:

Any thoughts on JScheme?

Another edit:

Kawa works fine; I'm going to use it.

One last edit (should be the last one):

Now we're going to use Common Lisp (ABCL).

Answer 1

If you had left off the JVM requirement, I might have suggested ypsilon, since it was built by and for a videogame developer.

But for the JVM, Clojure would probably be the most sensible alternative, if only for the strength of its community right now. You may be able to find lots of people willing to help you out when researching performance problems.

Unfortunately, it may be hard to do an apples-to-apples comparison between Clojure and other JVM implementations of Lisp.

Assuming you are deploying to traditional PCs, rather than phones or small devices, and that your game project is not particularly resource-intensive, your biggest concern probably won't be absolute memory utilization, but hiccups caused by garbage collection pauses. So, in evaluating Lisps, you may want to run some tests to figure out whether there are differences between them in how often garbage collection is triggered, even if it is just caused by different strategies in newing objects. But you'll also have some of the same opportunities to tune garbage collection behavior yourself, by being careful with object creation, or sensible use of weak/soft references, or even just using command line tweaks JVM gc options when you start up the app.

You could also try building some benchmarks that are useful to you, and test whether different JVM Lisps exhibit different characteristics. A number of people have invested research into profiling Lisp; see, for example, http://openmap.bbn.com/~kanderso/performance/ and consider whether some of the approaches linked there would be relevant for your application.

In at least one set of tests, http://per.bothner.com/blog/2010/Kawa-in-shootout/ , Kawa performed somewhat better than Clojure on many tests. If that's a major consideration, you may want to at least explore whether similar benchmarks apply to your case or not.

It doesn't sound like you are overly concerned with this, but if a (nearly) complete common Lisp implementation were important to you, Armed Bear Common Lisp might be a better place to start than either of these. I like it just for the name, but that's probably not a good enough reason.

The biggest challenge of answering a question like "which is best for..." is the implicit, unstated "by some measure of best." For me, the strength of a community around a technology is often at least as important as the performance considerations, since I rarely develop in a complete vacuum.

Answer 2

I think the hot lisp-like JVM language is clojure

There seems to be really good tool support. You'll also have access to the entire JVM stack, assuming that is appropriate for your game project.

Answer 3

I've sucessfully used Clojure to write a simple game - http://mikera.net/ironclad/

My thoughts on Clojure as a game programming language:

• It's easily fast enough overall, although you do need to learn a few optimization tricks (such as using static type hints to avoid reflection and using primitive artithmetic rather than the nice-but-slow BigInteger arithmetic)
• You get the benefits of being able to use all the Java libraries for graphics, IO etc. Some of these have Clojure wrappers already but such wrappers are not really essential - you can just call the Java libraries directly if you like.
• Clojure is stylistically more of a functional programming language than other Lisps - this can take a bit of getting used to for game programming although once you pick up the techniques it is very powerful
• The Clojure concurrency features are great for games - managing network events, user input, parallel processing of AI etc. was all a breeze.
• Macros are great for games! Not only do they help you with writing some of the thornier game logic, the fact that they run at compile-time can enable some neat performance optimisations.

Overall - very happy with Clojure for game programming, would have no qualms about using it again for another JVM game project - only exception would be a pretty intensive 3D game in which case it probably go for Java directly (maybe using Clojure as a scripting language)

Answer 4

As I understand you like functional languages but you don't want to deal with lack of good libraries. I assume you are an aspiring game developer.

In that case your only realistic option is to go with c++. C++ historically developed as a tool for making games and all of the libraries such as DirectX and many other tools will only work for c++.

The advantages of functional languages do not out-weight the benefits of C++ in the gaming arena, not by far. I know it sucks and I would also prefer to use functional languages but such is life. You would have to reinvent the wheel A LOT without c++ and you probably won't get very far on a serious project.

Take advantage of the mountain of tools developed with c++.