Back to the future

If you look at the programming language history poster there's a bunch or arrows leading to Java genesis, one of which comes from Smalltalk. Ok, I heard about Smalltalk and saw some code in books. I also knew that Gilad Bracha was one of the authors of Strongtalk (Smalltalk with static types) and later immensely contributed to Java evolution while working at Sun. I also saw references to this supposedly great language called Self in some programming language articles. But only now I see how it all linked together thanks to Avi Bryant's Keynote at RailsConf (yeah, of all places to learn about Java...) so I decided to transcribe here a small portion of this fascinating talk.

"There's a legend that there's something inherently about Ruby that makes it hard to implement a fast VM for it, because of open classes, because of dynamic typing - there's something about meta-programming, something about Ruby that makes it hard in this day to make it run fast. And it's just not true! It was true 20 years ago - it was a hard problem, but people solved it.

This is actually from Sun site, this is a bunch of papers that collectively explain how do you make Ruby go fast. But you'll note that they're written in 1989-91, you can go and look at the URL here, they come from the Self project. And the history is kind of interesting here, so since this is about the future and about the past, I'll give you a really brief history.

Self was a project at Sun to do Smalltalk, but even more so. Even purer object-oriented. And it meant that they had to find ways, because they wanted to make it so object-oriented, so pure, so turtles all the way down, they had to find more and more ways to make it go fast. And the technology they came up with was so interesting that they actually spawn off a start-up to try to implement new super-fast Smalltalk that was gonna be used on Wall Street. But before they got to release it, this was gonna be called Strongtalk, before they got to release it, Sun bought them back.

And Sun used the technology, used the HotSpot profiling and Just-In-Time compilation technology that have been developed here to build the Java VM. Which is sort of one of the great tragedies of technology, but it's true, that Java HotSpot VM in fact is what came of all of this great work of making dynamic languages go fast - of course they crippled it so that it doesn't make dynamic languages go fast anymore, but maybe that'll change. One interesting footnote to this is that a lot of the engineers that were involved in that have since left Sun and are back to doing Smalltalk."

JRuby pod-cast

I almost accidentally got to hear Neal Ford's interview about JRuby this morning.

Love it or hate it, Ruby cannot be ignored. Yet the articles and blog-posts you find on Ruby vs. Java are many times so emotional and single-minded that it became a really good joke. But not this one.

Neal starts with a bit of history, goes through Ruby comparison to Java (expressive power, meta-programming capabilities), the rising importance of JVM as a multi-language platform, comparison between JRuby and other JVM languages (Groovy, Jython, Jaskell, Scala) when to use them and how to get JRuby into your corporate development environment (the tips include - "don't say the word Ruby as long as it runs on the JVM" and "use it in test or build environment first - Ruby has great advantages there and it's easier to justify a new tool for build or test than for production") and finally about his work on first commercial product developed entirely in JRuby - the agile team management suite called Mingle.

I also liked his general comments regarding how G0F design patterns illustrate language deficiencies, his objection to XML programming and why the concept of protective programming environment allowing to scale software development through hiring zillions of bad programmers is bankrupt.

P.S. Martin Fowler, Neal's colleague at ThoughtWorks, recently blogged about JRuby too.

Functional programming for the JVM

Dear Java, my good old friend, there is something I need to tell you. You've been my only one for over 10 years, but now I have trouble staying faithful. It's not you, it's me. And no, I am not moving out, not just yet, because I can't afford to leave all your stuff behind.

But you don't satisfy all my needs anymore!

I know you are trying, dear, and good people try to help you - here Neal Gafter is working hard to give you closure support, Ricky Clarkson, a true alpha-geek who played with the first prototype of Neal's work, has blogged the results. But, sorry love, I can't wait until the big makeover in Java 7. What do you expect me to do with all these JVM languages around? These languages inter-operate (well, to certain extent) with your libraries, so I can enjoy all the usual stuff but I can also be more expressive. Here is an example of hooking up JRuby with Velocity and another one of writing servlets in Scala under Tomcat.

You wanna know who they are? Among the young ones, Scala deserves to be mentioned first, alongside Ruby, JavaScript and Python to name just a few. Classic ones include several Lisp dialects (e.g. Clojure and Common Lisp), Scheme and OCaml implemented over the JVM as well. Either there is a compiler that produces bytecode, or there's a JVM scripting engine, and sometimes both. I hope one day to make a deeper study and produce a proper comparison table, maybe then you'll understand.

You think that closures alone aren't good enough reason to have a little flirt on the side with another language? Hmm, consider the fact that "the other language" may offer me hot-swapping of classes, mix-ins, better modularity, pattern matching, better concurrency model and dynamic typing support ... who can blame me for being tempted.

Still loving you, yours truly but... not entirely.