I am finally back from a week of travel. Funny, it feels like much more than a week – but I guess that’s because there were some interesting mishaps with some of the flights.

Last Sunday I traveled to Berlin to attend RailsConf Europe. I arrived kind of late and was really tired and out of it during the Monday. I didn’t find most of the tutorials going on that enlightening – though it was fun to see David, Aslak and Dan present on RSpec together. I liked the mind map format they used instead of regular slides. Due to general tiredness and a really bad migraine I went to bed early. But before that I managed to see Dave Thomas introductionary keynote. It was interesting and extremely well presented; the theme was art and how it can help you as a programmer to use this metaphor to understand the things we do more closely. I didn’t find anything really new in the presentation and I’ve heard several people say that they would prefer if Dave had spent some time talking specifically about Rails instead. I tend to agree.

The second day of the conference was really good. DHH delivered a keynote that basically said that there is nothing really new happening with Rails. After that it was time for sessions. I guess none of the first presentations made any real impact on me, since I don’t remember what they were. After lunch I saw Nic Williams talk on meta programming; the talk was really fun. I didn’t learn anything new, but I had a fun time while doing it.

Charles and Tom did their JRuby presentation. And I also saw Evan Phoenix Rubinius talk. It was very interesting – if I could stand programming in such a low level language as C, I would probably spend more time helping them than I do now. I will write more about Rubinius – probably tomorrow – I haven’t really said everything I need to say here.

After the sessions there were more keynotes. Roy Fielding talked about REST. I gotta admit I didn’t really hear much of it though, since I was spending time fixing an annoying bug. After that Craig McClanahan talked for a few minutes about Rails. It was very enlightening to know how well regarded Rails is within Sun. Some people seems to have a different view on all this though, seeing conspiracy and dirty dealings in the way Sun is working Rails. I’ll need to cover that in a separate blog post too.

ThoughtWorks threw a party after the days session. That was very fun and well attended.

All the JRuby team attending (Charles, Nick, Tom and me) gathered together on the evening and did a JRuby Q&A BOF. Lots of people there, and a very free form of presentation made this one of the highlights for me. I had great fun and I hope the audience did too.

Finally the Wednesday… Cyndi Mithell from ThoughtWorks did a very nice keynote about why Ruby and Rails may be ready to cross the chasm and get a strong hold in the enterprise.

Koz and Marcel did a very good Rails Best Practices session. Down to earth, simple, totally useful advice on things to avoid in a Rails application and what to do instead.

And then it was time for my presentation about JRuby in ThoughtWorks. I think it went very well, but it became a little bit too corporate for my taste. I’ll need to make sure that doesn’t happen the next time. Maybe some more code in the presentation? =)

Most of the rest of the day was spent networking, hanging out in the exhibit hall and stuff like that. And then RailsConf was over.

My flight to Sweden from Berlin that evening didn’t really happen as I had expected it too. Instead I had to spend the night on a hotel in Frankfurt and take an early flight from there to Gothenburg.

Overall I had a very good time at RailsConf this year. It’s a worlds difference from RailsConf last year in London, which I felt was a real waste. This year the energy was high, much interesting things going on and lots of nice and smart people. Not as good as RailsConf in Portland earlier this year, but still very well worth attending. It seems that RailsConf has found a good balance in sessions. The only thing I can wish for would be more interesting choices for the tutorial day.

2 Comments | By Ola Bini | In: Uncategorized | tags: jruby, railsconf, railsconfeu, rubinius, thoughtworks. | #

Last week I decided it was time to get Ruby-DBI working with JDBC. I resolved to get on it since it would be highly useful and probably not so hard either. But as it turned out I didn’t really need to do anything. The work has already been done by Kristopher Schmidt. Very nice. So instead, this post will detail how to get it working with JRuby.

First download the Ruby-DBI distribution from RubyForge. Secondly, unpack. The third step is to configure and install it. Execute these commands inside the Ruby-DBI directory:

jruby setup.rb config --without=dbd_sqlite,dbd_sybase
jruby setup.rb setup
jruby setup.rb install

Now you should have Ruby-DBI installed, but no DBD drivers. Verify that it’s actually installed by running “jirb -rdbi”. The next step is to install the JDBC driver. First create a directory called $JRUBY_HOME/lib/ruby/site_ruby/1.8/DBD/Jdbc. Download Jdbc.rb and JdbcTypeConversions.rb and put them into this directory. Also make sure that the JDBC driver you want to use is on your CLASSPATH. Now you can create a script like this:

require 'dbi'

DBI.connect('DBI:Jdbc:mysql://localhost/test', 'test', 'test',
                 'driver'=>'com.mysql.jdbc.Driver') do |dbh|
p dbh.select_all('SELECT * FROM a_table')
end

Make sure that you include the name of the driver as done in this code. The first parameter should be the regular JDBC URI with DBI: first. In this case it’s the test database on localhost I connecting to, using the test username and test password. More information about how Ruby-DBI can be used can be found by Google.

9 Comments | By Ola Bini | In: Uncategorized | tags: jdbc, jruby, ruby-dbi. | #

So, for various undisclosed reasons it’s time to start seriously hacking XML. Now, the end artifact of this will be one of the few situations where XML is actually justified and makes this process better.

Of course, Emacs is a must for this challenge. I wouldn’t even try doing it without a real editor. Now, the undisputed king of XML in Emacs is nXML-mode. I want it everywhere. So the first step is to bring out Trang and convert all DTD’s into RelaxNG. Then edit schemas.xml and we’re running. Well, except for the simple fact that Emacs refuses to load anything else than xml-mode automatically. That sucks.

So after lots of looking, it seems there is a new magic-mode-alist that can look at the beginning of a buffer and “magically” decide what kind of buffer we’re dealing with. For some reason this behavior overrides my carefully laid out auto-mode-alist. Well. The solution for all you people is simple. Just add this snippet late in your loading process:

(setq magic-mode-alist
   (cons '("<＼＼?xml " . nxml-mode)
            magic-mode-alist))
(fset 'xml-mode 'nxml-mode)

1 Comment | By Ola Bini | In: Uncategorized | tags: emacs, nxml, nxml-mode, xml. | #

Put it down to my general ignorance – I’ve never realized that JavaScript has send/perform, and has had it for a long, long time. Of course, it only works for methods that exists on the object. Or? Is there any way of capturing non-existent method-calls/property look-ups like method_missing does?

Anyway, send:

function SendTester() {}
SendTester.prototype.foo = function() {
   print("Hello");
};

new SendTester().foo();
var name = 'foo';
new SendTester()[name]();

Please, tell me something more cool I’ve been able to do in JavaScript in browsers for 5-10 years but didn’t know about!

8 Comments | By Ola Bini | In: Uncategorized | tags: javascript. | #

With all the current talk of DSLs and concurrency, what I find lacking is discussions about how to combine the two. Of course, domain specific languages are incredibly important – they create a logical separation between the implementors of the business logic, and the people implementing the actual implementation of the DSL. Does it seem like a strange idea to want many DSLs to be able to run parallel to each other? I would imagine that in most cases a DSL that describes business rules and business logic is sequential in the particulars, but that there are also larger concurrency possibilities. This should be totally invisible for the business rule implementor in most cases – the runtime system should be able to run everything as efficient as possible.

A natural way of looking at DSLs is as declarative languages. In many cases that’s the way you write them (just look at the ActiveRecord API. it looks very declarative – it just happens to be implemented using imperative primitives). Now, if the language is truly declarative it should be side effect free. In the end, that isn’t a real goal, but if it would be possible to clearly understand which parts of the rules are using side effects, the rest of the implementation should be able to run totally concurrently.

These kinds of things should be possible to implement in any language with sane multi threading/multi processing. That said, I wouldn’t want the task of doing it with Java’s concurrency primitives if I can help it. So what kind of tools would be helpful? Possibly Erlang of course, since it’s already functional and that makes the identification of side effects much easier. Another possible alternative seems to be Gambit Scheme and Termite.

Anyone else thinking about these issues? Is there any research going on that would shed some light on it? And further, what’s the next step? Why haven’t this question already been discussed? It seems to be well time for it now.

4 Comments | By Ola Bini | In: Uncategorized | tags: concurrency, domain specific languages, dsl, erlang, gambit scheme, termite. | #

I’m starting to miss a few Common Lisp special forms more and more. To be more specific, I miss the family of declare/declaim/proclaim. I think a version of them could actually be extremely useful for Ruby. The current approach to String encodings in 1.9.1 uses a “pragma” inside of a comment on the first line of a Ruby file, like this:

# coding=utf-8

This works fine for coding, I guess, but I would like to have something more general – something that can be used inside of code too. As a typical example of the kind of thing I would love to be able to do, here is an example of a Common Lisp implementation of fib:

(defun fib (n)
(cond
  ((or (eql n 0) (eql n 1)) n)
  (t (+
      (fib (- n 1))
      (fib (- n 2))))))

As you can see, it’s the standard implementation. But, after this implementation is finished, I can continue by adding declarations:

(defun fib (n)
(declare (integer n))
(cond
  ((or (eql n 0) (eql n 1)) n)
  (t (+
      (fib (- n 1))
      (fib (- n 2))))))

This will help the compiler by telling that the n-argument is always an integer. You can also add more information to the declaration:

(defun fib (n)
(declare (integer n)
         (optimize (safety 0)
                   (speed 3)))
(cond
  ((or (eql n 0) (eql n 1)) n)
  (t (+
      (fib (- n 1))
      (fib (- n 2))))))

Now we’re looking at some directives about how the compiler prioritize between safety and speed. You can also add directives for how much debug information should be retained or if the compiler should improve speed or size. All of this is interesting, but if I compile it with SBCL I’ll get a few warnings. I’ve specified I want a high level of speed and low safety, but there are many optimizations that SBCL still can’t do, so it warns about them. In most cases it’s because there is no way to see if the result of the fib-operations return numbers, floats or rationals. If fib is seen as a bottleneck, the way to fix this is to add declarations inline the code in the style of this: (the numeric (- n 1)) and so on. This will allow the compiler to generate the best code possible.

Now, these kinds of changes are quite intrusive, and they aren’t really something you want all over your code base. That’s why you can do these declarations selectively, at only the places where it makes sense from a performance perspective to do it. By doing it correctly, Common Lisp code can be compiled to be incredibly efficient and fast, but very clean since in most cases you don’t add the type declarations at all.

This is also why Common Lisp is very good for rapid prototyping. You can get something working really quickly, but you can also change the code to be efficient later on with quite small changes.

I guess you all wonder what this has got to do with Ruby. Or maybe you don’t. Anyway – I want this in Ruby, or something equivalent to it. Not necessarily the exactly same thing, but something which in a standard way can add type declarations and also other things that can be interesting to know from a compiler perspective. It needs to be a keyword with specific syntax so the information is available before runtime. It should probably be used for the encoding declarations too, so it should be possible to use either at top level, or within class declarations , or method definitions. What do I want to be able to do? Well, type declarations is the first one. The second is compiler directives that can help improve code more than is possible right now. A typical example could look like this, maybe:

declare encoding: utf-8

def test_one(first, second, *rest)
 declare type: [Fixnum first, Enumerable second, Array rest]
 declare return: Fixnum
 declare compiler: [no-bindings, no-eval, no-closures]

 puts "hello"
 return 1+1
end

This code includes several things that would be very useful to know and would allow compilers like JRuby, XRuby, YARV, Rubinius and IronRuby to produce much better code. If we know that the arguments should always be specific types we can declare this and hopefully get better results. The return value is also usually the same type and declaring this can make code that uses this method more efficient. Finally, the compiler declarations will help with some of the pain points for currently compiling things efficiently. If no bindings, or evals or closures are used, the code generated will be much better.

This kind of information would be very useful not only for the compiler but also for tool support. If you know something should always be a specific type, you can add that as a declaration and things will automatically function better.

I know that this is kind of un-Ruby like, but I really believe there is great value to be had by adding this kind of declarations.

11 Comments | By Ola Bini | In: Uncategorized | tags: declarations, jruby, optional static typing, ruby. | #

After all discussions about the NBL and all surrounding issues, I realized I haven’t actually looked at what JavaScript 2/ECMAScript 4 will contain. I decided to do some research. What I found was mostly very old (2 years or so), but very enticing. If only half of it comes true, JS2 will be a power house. Of course, the C inspired JS syntax is still kind of repugnant, and it’s hard to see any kind of general purpose macro facility working on it. Pattern matching is the only reasonable way of getting macros in there, me thinks, and that just doesn’t pack the same power.

But still, there are seriously nice things there:

• Classes (the classic kind), packages and namespaces
• Destructuring
• Generators and iterators
• A real numeric tower
• Optional static typing

The end result is that JS2 will look much more like Java, but pack greater power in many ways. I wouldn’t say that I agree about JS2 being the NBL, but we’re still talking some nice innovation here.

8 Comments | By Ola Bini | In: Uncategorized | tags: javascript, javascript2, next big language. | #

I’ve just come back from Bangalore, India where I spent two weeks with intense learning, much socializing and incredible amounts of fun. In short, I’ve attended ThoughtWorks Immersion. I found it to be a singular experience, and something that will be immensely helpful during my career at ThoughtWorks.

So what is Immersion? Basically, it’s two weeks of learning that all ThoughtWorkers go through. The aim is not really to teach technical concepts or specific ways of working, but more to establish a common vocabulary, get everyone to understand the history of ThoughtWorks, and also give insight into all parts of the organization. How everything works and how we do things. A large part also is about what makes ThoughtWorks different from other companies, both in the way we do things but also the why of it all. The values TWers should share and what makes TW a unique place to work.

I feel I’ve learned incredibly much. The two weeks away from regular work was hard but definitely worth it. I wish all companies had something like this – but I guess that this is one of the ways that make TW a very different place.

The learning side was important, but the social aspect probably even more so. I now have 13 new friends within ThoughtWorks, spread all over the world. We had a good time together. Also, Bill Kimmel and Naresh Jain turned out to be outstanding teachers and very nice people to boot.

Of course, the stay in Bangalore got even more productive when Roy Singham, Chad Wathington, Cyndi Mitchell and a few other people arrived there. I spent some time with them, planning and scheming.

Meeting Håkan Råberg and seeing the cool stuff he’s working on (still secret) was also very nice.

All in all, two weeks well spent.

1 Comment | By Ola Bini | In: Uncategorized | tags: bangalore, immersion, thoughtworks. | #

Next week I’ll be in Berlin for RailsConf EU. I’ll be speaking about JRuby at ThoughtWorks, and hopefully I’ll meet lots of you there.

ThoughtWorks is actually massively involved in this RailsConf, and I’m hoping for the same kind of energy I observed at RailsConf in Portland.

See you next week!

No Comments | By Ola Bini | In: Uncategorized | tags: berlin, railsconf. | #

Bangalore, India – here I come!

2 Comments | By Ola Bini | In: Uncategorized | tags: india, travel. | #