Posts Tagged lisp

With just about one hour and a half to spare we managed to submit our entry for Ludum Dare 36. Ludum Dare is a regularly occurring, fairly well-known game jam the idea of which is to create a game from scratch in 48 hours by yourself or 72 hours in a team. Given that, unlike last time we tried to participate we actually managed to finish making something that resembles a game, I think it's worth noting what my experience was as well as my general thoughts on game programming in Lisp.

As I'm writing this I'm still in Krakow. Sitting next to me is Till, who joined me for ELS this year. It was a blast, but I'm also really exhausted and my throat is still hurting a bit from talking all the time the past three days. Our flight back to Zürich is in about an hour from now and I have a test to study for on the coming Thursday; I actually would've really liked to stay a bit longer, especially considering there were a few people I would've loved to talk to a bit more. Alas, you can't always get what you want.

I'm currently sitting in a lecture hall at the ETH in Zürich. It's 8 AM⁹ in the morning, and despite having had a long night's sleep, I'm still quite tired. It's amazing what two days of just listening and talking can do to you. It also feels so much longer than that, just because of all the things that happened. I suppose I should start from the beginning though.

Some deem it unfortunate, others are not bothered by it at all, but the fact remains that Common Lisp does not have a standard GUI toolkit. It does have a native toolkit called McCLIM, but due to general outdated-ness it is not a very attractive choice. Generally I'm not one to linger long on decisions when it comes to learning something, so after quickly evaluating the options I chose to try CommonQt, a library to allow using the Qt framework with CL.

I haven't come across this anywhere yet, but I think it's worth writing a quick entry about, just so that it's referable. So, writing tests is a common enough occurrence in programming and Common Lisp is no exception. The vast amount of testing frameworks is both a sign of the repeated desire to have a comfortable way to write tests and the general ‘I can do it better’ syndrome prevalent in Common Lisp. However, this blog is not about those things, but about another, much easier aspect: Running tests.

This confession is out of sequence because I wrote the initial sketch for it earlier and can only now publish it because it is rather heavy in code for a change and that required the new blog version. Anyway.

As I could not come up with an idea for a confession all day, I present to you two small Common Lisp utility packages I wrote today. One of them is actually useful since it provides a very convenient way to benchmark your functions. The other is a very minimal implementation of something shell-like in CL.

One of the more difficult concepts to explain is that of generic functions, the way Object Oriented Programming (OOP) is done in Common Lisp. Since a lot of people seemed to be confused about it even after having read PCL, I will try my best to explain this anew here.

Continuing on in my endeavour to wrap up some loose ends and missing chapters of PCL I'll take a look at ASDF and Quicklisp. Neither of these are required to use CL —even for large projects— but they can help tremendously to get things done quick. So, let's see what they do and how they may be of use to you.

While Practical Common Lisp is a superb primer on CL I feel like it doesn't cover packages and symbols early or in-depth enough as I still had to learn a lot about them afterwards. This topic as well as ASDF/Quicklisp and Slime/Swank are things that I'll talk about a bit in a few blog entries in the hopes that they may be useful to other people learning CL.

In an effort to get at least something productive done today I decided to take it upon me to talk a bit about my latest project, Parasol. I've attempted to write large GUI oriented applications before, but they never really went anywhere significant. This time seems to fare much better already though, as Parasol has, within barely a week, evolved into a tablet painting application with layers, history, infinite canvas and fancy colour pickers.