The Bay Area Clojure user group threw a special JavaOne special, with Rich Hickey as special guest on Wednesday afternoon. I went there and it turned out to be a large collection of former and current ThoughtWorkers there, among all the other Clojure enthusiasts. The model was lightning talks for a while and then general town hall with Rich answering questions. The reality turned out to be a bit different - firstly because people spent quite long on their talks, and people asked many questions and so on. The second problem was that the projector in the place had some serious problems - which basically ended up resulting in everyone projecting pink tinted presentations.

There were several interesting talks. The first one took a look at what the Clojure compiler actually generates. This turned a bit funny when Rich chimed in and basically said “that doesn’t look right” - the presenter had simplified some of what was happening. I don’t envy the presenter in this case, but it all turned into good fun, and I think we all learned a bit about what Clojure does during compilation.

There was a longer talk about something called Swarmli, which was a very small distributed computing network, written in about 300 lines of code. I defocused during that talk since I had to hack some stuff in Ioke.

After that, one of the JetBrains guys showed up the new IntelliJ Clojure plugin. It seems to be quite early days for it still, but there is potential to get good cross language refactoring, joint compilation and other goodies there.

Finally, my colleague Bradford Cross did a very cool talk about some of the work he’s currently doing at a startup. The work seems to be perfectly suited for Clojure, and the code shown was very clear and simple. Very cool stuff, really. ThoughtWorks - actually using Clojure at client projects. Glad to see that.

After that it was time for Rich Hickey. Rich decided to give a lightning talk himself - about chunked sequences. Very cool in concept, but actually one of those ideas that seem very simple and evident after the fact. Chunked sequences really seems to promise even better Clojure performance in many cases - without even requiring changes to client code.

After that there was a general Q&A session, where questions ranged all over the map, from personal to professional. One of the more conentious things said was about Rich’s attitude to testing. This caused lots of discussions later in the evening.

All in all, this was really a great event. We ended up at a nearby bar/restaurant afterwards and had long discussions about programming languages. A great evening.

3 Comments | By Ola Bini | In: blogging | tags: clojure, javaone, presentations, san francisco. | #

I’ve been spending the last few days in San Francisco, attending CommunityOne and JavaOne. We are right now up to the second day of JavaOne, so I felt it would be a good idea to take a look at what’s been going on during the first two days.

I will not talk about the general sessions here since I as a rule avoid going to them. So, I started out CommmunityOne seeing Guilloume talk about what is new in Groovy 1.6. Pretty interesting stuff, and many useful things. Although, one of the things I noted was that many of the default usages of AST transformations actually just make up for the lack of class body code. Things like “@Singleton” that neeeds an AST transformation in Groovy, is a very simple thing to do by executing code in the class body in Ruby.

After that I saw John Rose talk about the Da Vinci machine project. Pretty nice stuff going on there, really. The JVM will really improve with this technology.

Charles Nutter did a reprise of his Beyond Impossible JRuby talk. It’s a really good talk that focuses on the things that you really wouldn’t think possible to do on the JVM, that we’ve had to do to get JRuby working well.

Guido talked about Python 3000 - much of that was really a look at the history of Python, and as such was really interesting. Unfortunately, my jetlag started to get the better of me at that point, so my focus could have been better.

For me, the first day of JavaOne started out with the Script Bowl. This year the languages represented was Jython, Groovy, Clojure, Scala and JRuby. I think they all did a pretty good job of showcasing the languages, although it’s very hard to do that in such a small timeframe. I think I sympathized the most with Rich Hickey (creator of Clojure) - the reason being that the Clojure model is the most dissimilar from the rest of the languages. But this dissimilarity is actually the key to understanding why Clojure is so powerful, so if you don’t understand it, you’re just going to be turned of by Clojure’s weird surface semantics. (Hint: they are not weird, they are necessary and powerful and really cool). Rich did a valiant effort to conveying this by talking a lot about the data structures that is Clojure, but I’m unsure how much of it actually penetrated.

Tom did a great job with the JRuby demos - he had a good flash 3d game running using a JRuby DSL, and then some slides showcasing how much benefit JRuby gets from the Ruby community. Good stuff.

After that I went to Rich’s Clojure talk. I’ve seen him give similar talks several times, but I don’t get tired of seeing this. As usual, Rich did a good job of giving a whirlwind tour of the language.

After lunch I went to the talk by Konstantin about JetBrains MPS. I was curious about MPS since I’ve been spending time with Intentional lately. I came away from the talk with a pretty different view of MPS compared to going in, actually. My initial reaction is that MPS seems to be pretty limited to what you can do with Intentional.

Then it was time to see Yehuda Katz talk about Ruby - this was a great intro to Ruby and I think the audience learned a lot there.

The first evening of JavaOne was really crazy, actually. I ended up first going to Brian Goetz and John Rose’s talk about building a Renaissance VM. This was a bit of an expansion of John’s CommunityOne talk, and gave a good overview of the different pieces we’re looking at in JSR 292, and also other things that should be in the JDK in some way to make a multi-language future possible.

Tobias Ivarsson gave a BOF about language interoperability on the JVM. This ended up being more about the interface injection feature that Tobias has been hacking on. We had some pretty good discussion, and I think we ended up with a feeling that we need to discuss this a bit more - especially if the API should be push or pull based. Good session by Tobias, though.

And then it was finally time for my BOF, called Hacking JRuby. This was actually a pretty mixed things, containing lots of funny small pieces of JRuby knowledge that can be useful if you want to do some weired things with JRuby. The slides can be found here: http://dist.codehaus.org/jruby/talks/HackingJRuby.pdf. I think the talk went pretty well, although it was in a late slot so not many people showed up.

The final session of the day was a BOF called JRuby Experiences in the Real World. This ended up being a conversation between about 10-12 people about their JRuby experiences. Very interesting.

After that I was totally beat, and ended up going home and crashing. So that was my first day at JavaOne.

1 Comment | By Ola Bini | In: blogging | tags: clojure, communityone, javaone, jruby, presentations. | #

The first day of the proper QCon conference started out with Sir Tony Hoare doing a keynote about the difference and overlap between the science and engineering of computing. Fairly interesting, but the questions and answers were much more interesting stuff. One of the more interesting points made by Hoare was that in his view, a full specification is a generalization of testing. After the keynote I started out my track called Emerging Languages in the Enterprise. I introduced this track, doing 15 minutes of talking about my views on programming languages. The slides for my piece can be found here: http://olabini.com/presentations/ELITE.pdf. My talk was made much more interesting by Tony Hoare being in the front row. That made the whole thing a bit more daunting, obviously… =)

I then spent the rest of the day in my track - which was very good. I am very happy with all the presentations, and felt the track was a great success. First of was Michael Foord, talking about IronPython, and how Resolver uses IronPython to create a great product. Some interesting lessons and information there.

After lunch Jonas Bonér talked about Real-world Scala. The presentation gave a good grounding in Scala without looking at all small details - instead Jonas talked about more high level concerns and styles.

After that, Rich Hickey did a great presentation about Clojure. Rich did a great presentation, talking about Clojure from the ground up. It was very well received.

Martin Fowler did a fantastic presentation on ThoughtWorks experience with Ruby. The room was packed for this.

The final presentation in my track was Attila Szegedi talking about JavaScript in the Enterprise. This was also a great presentation, and gave me some new insight into what you could achieve with Rhino.

All in all, the full track was excellent, and all the presentations achieved pretty much what I hoped from them. I learned a lot from all of them.

After the final session of my track, Martin Fowler and Zach Exley did the evening keynote, talking about how technology helped the Obama compaign. Very interesting stuff too. At the end of the day, a very good day at QCon.

1 Comment | By Ola Bini | In: blogging | tags: clojure, ironpython, javascript, presentations, qcon, qcon london, ruby, scala. | #

I know I’ve mentioned Clojure now and again in this blog, but I haven’t actually talked that much about it. I feel it’s time to change that right now - Clojure is in the air and it’s looking really interesting. More and more people are talking about it, and after the great presentation Rich gave at the JVM language summit I feel that there might be some more converts in the world.

So what is it? Well, a new Lisp dialect for the JVM. It was originally targeting both the JVM and .NET but Rich ended up not going through with that (a decision I can understand after seeing the efforts Fan have to expend to continue providing this feature).

It’s specifically not an implementation of either Common Lisp nor Scheme, but instead a totally new language that’s got some interesting features. The most striking feature of it is the way it embraces functional programming. In comparison to Common Lisp who I characterize as being a multiparadigm language, Clojure has a heavy bent towards functional programming. This includes a focus on immutable data structures and support for good concurrency models. He’s even got an implementation of STM in there, which is really cool.

So what do I think about it? First of all, it’s definitely a very interesting language. It’s also taken the ideas of Lisp and twisting them a bit, adding some new ideas and refining some old ones. If I wanted to do concurrency programming for the JVM I would probably lean more towards Clojure than Scala, for example.

All that said, I am in two minds about the language. It is definitely extremely cool and it looks very useful. The libraries specifically have lots to say for them. But the other side of it for me is from the point of Lisp purity. One of the things I really like about Lisps is that they are very simple. The syntax is extremely small and in most cases everything will just be either lists or atoms and nothing else. Common Lisp can handle other syntax with reader macros - which end up with results that are still only lists and atoms. This is extremely powerful. Clojure has this to a degree, but adds several basic composite data structures that are not lists, such as sets, arrays and maps. From a pragmatic standpoint I can understand that, but the fact that they are basic syntax instead of reader macros mean that if I want to process Clojure code I will end up having to work with several kinds of composite data structures instead of just one.

This might seem like a small thing, and it’s definitely not something that would stop me from using the language. But the Lisp lover in me cringes a bit at this decision.

All in all Clojure is really cool and I recommend people to take a look at it. It’s getting lots of attention and people are writing about it. Stu Halloway is currently in the process of porting Practical Common Lisp to Clojure, and I recently saw a blog post about someone porting On Lisp to Clojure, so there is absolutely an interest in it. The question is how this will continue. As I’ve started saying more and more: these are interesting times for language geeks.

10 Comments | By Ola Bini | In: blogging | tags: clojure, lisp, programming, programming languages. | #

If you haven’t already seen this, let me totally recommend Stuart Halloway’s series on the languages he call Java.next. The series look at several different aspects of these languages (Groovy, Scala, Clojure, JRuby), contrast them with each other and Java. Highly recommended if you are in any way interested in the languages that will soon replace Java for much application development.

The three published parts are:

1. Java.next: Common Ground
2. Java.next #2: Java Interop
3. Java.next #3: Dispatch

2 Comments | By Ola Bini | In: Uncategorized | tags: clojure, groovy, java.next, jruby, polyglot, scala. | #