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Mountain West Ruby Conference: JRuby by Charles Nutter and Ted Enebo
16 March 2007

Most of the developers in the auditorium have been Java programmers, and don’t
want to go back. Charles said that they have a hard time getting the message
out that JRuby isn’t about Java, it’s about Ruby, and they’ve aimed to make
JRuby as compatible as possible with Ruby.

Background: They’ve both been Java developers for the past ten years, and
their goal is to make Ruby a first-class language on the Java platform. They
didn’t start the JRuby project — they adopted it.

Ruby 1.8 Design Issues:

• Green Threading doesn’t scale across multiple processors/cores. The
  one-size-fits-all scheduler doesn’t fit all platforms where it runs. Although
  Ruby 1.9 will use native threads, there’s much work left to make it work on
  various platforms. Java/JRuby already uses native threading and scales across multiple processors and cores.

• Partial Unicode support. Ruby 1.9 will have Unicode support, but will bring with it other difficult issues (e.g. what happens when you concatenate two strings, each being in a different encoding?). In JRuby, one can use Java Unicode strings, or the Rails Unicode library.
• Slower than most other dynamic languages. Makes it difficult to sell to management. It’s a long term perception problem for the language. JRuby will allow compiling to bytecode, which allows HotSpot to do JIT optimization.
• Garbage collection is simplistic. JRuby uses Java’s best-in-the-world memory management and GC. Scales well to enormous applications and loads, and is battle-tested in deployments worldwide.
• C language extensions can crash the Ruby runtime, don’t necessarily interact well with garbage collection or with threading. JRuby lets you use Java-based extensions, which aren’t going to crash the VM.

Politically, it’s easier to get JRuby into an organization than Ruby, because
organizations have already accepted and deployed Java. JRuby is just a library for Java.

Most “pure” Ruby code runs on JRuby, and Rails mostly runs on it, although
only 90% of ActiveRecord passes unit tests. It’s easier to write JRuby code
than Java code. Perhaps Java is good for implementing libraries, and JRuby is
good for using those libraries for implementing applications.

JRBuilder/Cheri project by Bil Dortch lets you build Swing apps in JRuby much
more easily than writing Java code. Demo shown. Project is still in development.

NetBeans Ruby support is a one-man developer effort by Tor Norbye. His
progress has been impressive. Demo shown. Code completion, syntax
highlighting, built-in ruby documentations, go-to-declaration, auto-indent,
rename support, built-in interactive ruby shell (irb). By the way, Charles
uses vim, and Ted uses emacs. NetBeans Ruby uses the JRuby AST to do its work.

Speed. Interpreted JRuby is currently generally slower than Ruby 1.8.5, although some things are faster. They’re working on making it faster, and should be able to achieve comparable performance to Ruby 1.8.5. Compiled Ruby (bytecode) runs faster on the JVM than it does on Ruby 1.8.5.

Q: How can you make a JRuby app deployable so that people don’t know it’s a Ruby app or a Java app?
A: Make your ruby app into a jar file, and just double-click it.

Q: How easy or hard is it to deploy JRuby apps to servers?
A: Use Sun’s glassfish deployment framework.

mtnwestruby: Review of a Rails App by Marcello and Jamis of 37signals.com
17 March 2007

Almost everyone in the audience has used Rails. A little less than have write Rails apps for a living. I haven’t used Rails, and even if I had, it would be difficult to take notes on this presentation. I recommend viewing the video when it becomes available.

Marcello and Jamis recommend Kent Beck’s book on Smalltalk best practices and how to decide what code belongs where. They also recommend Domain Driven Design.

Why do you prefer the operator ‘&&’ over ‘and’? The use of ‘&&’ leads to fewer bugs. Consider the following code:

• return foo and bar # will not return what you expect
• return (foo and bar) # this will work
• return foo && bar # use ‘&&’ and ‘||’ because they’re more predictable in behavior than ‘and’ and ‘or’

Convention: A bad smell in code is seeing a chain of if..elsif
statements to check for error conditions. In this case, you probably want to
handle error cases with exceptions. For example, in Rails, myobj.save! will
validate data, and raise an exception when there’s a problem, whereas
myobj.save will not raise an exception.

mtnwestruby: Ruby USB by Michael Hewner
16 March 2007

Nerds love to customize their software — their shell prompt, adding vim plugins, emacs, etc. After a while, they run out of things to customize. What do they do now? Customize USB hardware!

Ruby USB is about fun, about controlling USB devices using Ruby. No
one paid him to work on it. USB devices are self describing. You can even build
your own USB devices, which has nothing to do with Ruby. The most interesting
USB spec is the one for Human Interface Devices. For HID, the device sends a
description of the format of the data that it’s going to send and what it means
— before it actually sends the data. No reverse engineering necessary!

Ruby USB simplifies the interpretation of the meta-data coming from a USB
device.

mouse_interface.all_input_usages => [Button (9)::Button ...]
keyboard_interface.all_input_usages # will list ever key available on the keyboard

Michael did not write libUSB; his Ruby library merely uses it. It supposedly
supports all UNIX operating systems, although he’s only tested it on Linux.

Lessons learned:

• Don’t write the USB HID parsing library in C++ and patch it into Ruby — it’s too much work. He should have written it directly in Ruby.
• Write unit tests.

AVRUSB: Build your own custom USB device — requires that you have a soldering iron and an AVR microcontroller.

Evdev uses the linux-level USB device layer to let you talk to USB devices. It’s easier to use, more rock solid, but doesn’t let you do as many cool things.

Q: Is Ruby USB ruby-thread safe?
A: Haven’t tested it. There are probably some bugs.

Q: Do you have the ability to send output to USB devices?
A: He’s working on it. It’s almost ready.

Q: What’s the craziest thing you’ve done with Ruby USB?
A: Glued two keyboards together. Made one work for Vi insert mode, and one for Vi command mode. It didn’t work out well because he would frequently type on the wrong keyboard, and because it was too large to fit on his lap comfortably.

mtnwestruby: RubyCLR and Ruby.NET by John Lam
17 March 2007

John works for Microsoft. Before coming to Microsoft, he built the bridge for running Ruby on the CLR (common language runtime).

Why would anyone want to run Ruby on someone else’s virtual machine? To answer
that, we look at the overlap between what we want to do and what we actually
do at work. It would be nice to maximize that overlap. Many of us want to use
dynamic languages, by many of us have to use .NET or Java. Running dynamic
languages on the one of these VMs helps maximize the overlap.

The interop layer for Python is going to be fundamentally different than that
for Ruby so that when you write a Python program using .NET libraries, it still
feels like Python code, and when you write Ruby code, using .NET libraries, it
still feels like writing Ruby code.

Lutz is an MS employee that worked on Intentional Programming, which never went
anywhere at MS. He created an editor that would parse the AST (abstract syntax
tree) and display it in different ways. This idea lives on in the .NET
Reflector, which will decompile .NET assemblies into IL, Visual Basic, C#,
Delphi, etc. It’s interesting to use Iron Python to compile code, and use the
.NET Reflector to look at the IL.

Dynamic methods are an interesting feature of the CLR in version 2.0. If they’re not going to be used, they get garbage collected. Before 2.0, once you load code, it stays loaded for the lifetime of the VM.

Interesting: The CLR supports polymorphic methods based on the return type, not jus the arguments. This isn’t a feature that C# supports.

The Ruby to .NET interop is extremely fast — millions of operations per
second.

John used Vim on Windows when he edited code.

On April 30th at the MS mixed conference, we will see the interesting things
that John Lam has been working on since he joined Microsoft, which he can’t
talk about right now. However, the really interesting conference will be Microsoft PDC because the technology will be more mature.

Q: Can you run Rails on the Ruby CLR?
A: No idea.

Q: Can I run Ruby.NET on mono or on my PowerPC?
A: There’s nothing that would preclude it from running on Mono, but Microsoft is not working on it.

Mountain West Ruby Conference: Lightning Sessions — Five minutes each.

16 March 2007

Mike. BinaryLottery uses ‘figlet’ to translate strings to ASCII art.

WAX by dan@eparklabs.com. WAX – Web Application X — A similar thing to Rails, but a totally different concept. Strongly tied to the database. Extremely fast development for enterprise database applications. Used by 10% of Fortune 500 companies, although they don’t know that. Self-contained applications. Designed with CSS. Website/CMS and Applications are integrated. REST architecture. Start with “wax on”. Stop with “wax off”. Allows you to GET and POST Excel spreadsheet files, among other things.

Managing SSH keys with Capistrano by Jade Meskill from Pheonix, AZ. Capistrano takes all developer’s SSH public keys, and puts them into an authorized keys file on the remote boxes they need to deploy software to. http://iamruious.com

Goldberg presented by Coby Rhenquist. He found that Rails leaves developers to themselves after getting their application framework stetup. Then he found the Goldberg generator, which gives you a more complete site, including better looks, a login page, users, roles, permissions and built-in CMS (textile), etc. Gives the administrator the capability to wire things up using menus in the web UI front end. Goldberg.rubyforge.org. Disadvantage: When rails 1.2 comes out, you have to re-do your app.

CruiseControl.rb 1.0 was just released. http://cruiseControlrb.thoughtworks.com It should take about 10 minutes to download and install. No XML or XSLT as with Java CruiseControl. Not released as a gem.

JRuby deployment. Charles Nutter. Just released JRuby Rails Integration.

$ rake war:standalone:create

JRuby has better database support than Rails because of JDBC.

LogWatchR by Pat Eyler (uses Suse Linux and vim). Concepts: Simple, Extensible, Low Support costs. Uses YAML to specify good and bad patterns. LogWatchR saves statistics to that YAML file as well. Written in 250 lines of Ruby. Handles 2250 log entries/sec. Likes Ruby because it’s easy to write, easy to read, easy to maintain.

Mountain West Ruby Conference: SBN
Tag: mtnwestruby
16 March 2007

James Britt – Black-boxing with Ruby

Reinventing the wheel is overrated. Why not reuse what other people have already implemented, even from other languages?

Trac: A good project tracking system. Requires too much use of the mouse.
What if: I could use Trac from the command line? Tracula.

Tracula is written in Ruby and uses Hpricot & Mechanize to pretend to be a web browser. Unfortunately, tracula is brittle because the web page UI tends to change — it’s not an API they’re publishing. Many features are missing from Tracula, but that’s ok — he writes the functionality as he needs it, and stubs out missing behavior with hardcoded values.

Tracula acts as a proxy, so the code using tracula doesn’t break just because trac changes.

WordPress: A best of breed web log system.
What if: I could have the great comment system for the Django Book?
www.djangobook.com. Uses Yahoo UI and Yahoo.EXT.
Comet is written in Ruby. Comments made by users are redirected via Apache modprox through comet, which takes the comment, and posts it to WordPress.

Lessons learned:

• WordPress plugins are the way to go.
• Repurposing other people’s code can bite your hard.
• Most web sites offer APIs, including TRAC. Use them, but still use a proxy layer so your software is insulated from changes in the API.
• Proxies can add exception handling that is missing from APIs.

Techniques:

• Screen scraping
• DOM munging
• Proxies, proxies, proxies!
• Save off a copy of web pages while you are developing your HTML screen scraper, and hit those saved pages so that you don’t run up someone’s bandwidth bill.

Mountain West Ruby Conference: Ruby Implementor’s Panel
16 March 2007

Ruby on Parrot has a JIT and garbage collection. Needs to be polished. Has an interop convetion so languages can call into each other. Bytecode runs on most common hardward — Intel, PPC.

John Lam – CLR Ruby: CLR naming conventions are nothing like Ruby naming conventions, but you want to make the interop look like Ruby. CLR was originally envioned to be a static language runtime, so there are similar problems as for the JRuby guys. The CLR platform gives you some things “for free”, like debugging support.

Edwin Pheonix – Rubiness: Rubiness is designed new, from the ground up, and meant for Ruby. The idea is to keep it small and simple while supporting full Ruby. Goal is to hit 1.0 by October. It will be 1.8.5 compliant and support Rails 1.2.

Charles Nutter & Tom Enebo – JRuby: Will release 1.0 in the next couple of months. Goal is to get it faster.

Question and Answer Session

Performance

• Nutter: The language shootout posted recently was pretty good. JRuby is about twice as slow as Ruby, although some things are starting to run faster. When compiled, JRuby runs faster than Ruby.
• Ty: Slowly seeing more performance as they work on it.
• Pheonix: Rubiness is slow and makes the other implementations look awesome. Up to this point, he has done no performance tuning. Since the language shootout, he’s put some time into it. He was beating Ruby 1.8.5 on some of the benchmarks.
• Lam: Iron Python is the fastest python out there, depending on who’s benchmarks you believe. This proves that using the CLR is viable. Compile chunks of dynamic code, and garbage collect them later.
• Parrot Guy: Parrot is able to beat C code in some cases, similar to the JVM + Hotspot. Speedups as much as 1.5x over Perl 5, but it depends on what you’re doing.

What features of the Ruby language are the most problematic?

• Pheonix: Continuations are one of the easiest. Dynamic dispatch is a pain, but it’s a fundamental language feature. Eval.
• JRuby: Emulating Ruby’s threading model. Eval is a pain, which is why they have a mixed mode interpreter. Compatibility with esoteric features —
• Pheonix: An esoteric feature is like what you can take in as a block argument.
• Ty: How many people have passed Nil as a block argument? ….
• Pheonix & Nutter: Who here has used ‘retry’ from a block? (one person). Do you know what it does? (no). It re-runs the code.
• Parrot Guy: The dynamic nature of the language makes it difficult.

What advantage does your VM give?

• Parrot Guy: Interop with already written libraries — SQL, etc.
• Lam: You get Profiling, Debugging, Code coverage for free. Auto-complete in IDEs.
• Pheonix: The possibilities are wide open right now. Re-write the byte-code on-the-fly if you want. His goal is to build a platform for other people to get their work done — an extensible VM.
• JRuby (Nutter): Interop with Java libraries. Most companies already have and use Java, so there is much to leverage.
• Ty: How many people have trouble getting Ruby deployed in their environment? (No one — everyone here uses Ruby already)
• Pheonix: Deployment is a big issue. How do we distribute applications without having to ask people to install a VM?

How do your implementations deal with Unicode?

• JRuby: JRuby can use the Rails multi-byte library natively, or uses the Java unicode support.
• Pheonix: Rubiness doesn’t have Unicode, but he’d like it to.
• Parrot Guy: Parrot supports unicode. It’s not that hard to make Unicode work most of the time, today.

Is there a website for a formal specification of Ruby?

• Nutter: I’m still running the website in my basement, and sometimes people contribute to it. http://headius.com/rubyspec — it’s a community spec for Ruby. Few people are clamoring for a spec, except for the people doing alternative implementations.

Is there a common benchmark suite?

• Pheonix: Believes that each implementation will have their won benchmark suites. However, they will run each other’s benchmark suites.
• Nutter: We’re running the test suites that have been written so far, including Rubycon. See the “ruby test” project on Ruby forge.
• Pat Eyler: Various gems will automatically be run against the different VM implementations, and results submitted to the VM implementors.

Why not compile to C code?

• Pheonix: There are many things in Ruby that don’t map to C. Two or three projects to this end have stalled.
• Lam: Iron Python compiles down to static assemblies, so it’s possible to go from Ruby to assembly code, although it still leverages the CLR libraries, garbage collector, etc.
• Nutter: Why re-invent the wheel of a garbage collector, the VM, boundary between libraries? People have worked hard to implement general purpose VMs, so let’s leverage their work.
• Lam: Interpretation isn’t as horrible as it seems. (I overheard him say: Slow application startup time is a problem. Microsoft employs a lot of lisp refugees.)

Mountain West Ruby Conference: SBN
16 March 2007

Carl Youngblood. Simple Bayesian Networks with Ruby.

How do we handle uncertainty? Probablilty theory.
How do we come up with probabilities? From experience, from beliefs — but either of these may not be accurate because of too few samples or skewed samples.


gem install sbn


The Ruby version is faster than his C++ version. Premature optimization is the root of all evil. — Donald Knuth

xmlbif – the format that the bayes network is stored to and read from. Compatible with the Java Bayes package. See http://en.wikipedia.org/wiki/Bayesian_network

He couldn’t get his SBN demonstration program working as expected. Sounds like SBN isn’t ready for prime time. Future improvements:

• Exact inference
• True continuous variables
• Etc.

http://www.pixelglow.com/macstl/

Q: Why not do this in R, and connect R to Ruby?
A: Good idea.

I think it would be cool if someone showed how to connect SBN into CruiseControl.rb to identify what patterns of development and which developers are most likely to break a build.

Mountain West Ruby Conference by Gregory Brown
16 March 2007
Pragmatic Community Driven Development in Ruby. Or “Rolling the dice with Ruport”. “Reporting Sucks”.

Gregory spent several minutes at the beginning of the presentation trying to get his Nvidia X display settings worked out for both the projector and his screen. None of the other people using Linux desktops had the same problems, and neither did the people using Windows or Mac OS X.

Ruport couldn’t have happened without a community to support it. Community = people + problems. Why is community important? Community helps root out bad ideas, and we all have bad ideas. With a good community, you can discover bad ideas sooner, and replace them with better ideas (hopefully).

How do we leverage community? One aspect is to pick a license that encourages people to get involved.

What license do we choose? Licenses aren’t as easy to “refactor” as code. Choose a license that is “right” for your project. Don’t write your own. In order to be taken seriously at a community and at a corporate level, pick one of the already approved OSS licenses. Picking a license is a compromise.

BSD/MIT favors individuals.
GPL favors communities.

Reporting is a big domain. Sometimes, it’s necessary to integrate with software with less than ideal licensing terms. The Ruport community chose the Ruby License.

Communities are idea warehouses.

You can only really work passionately on your problems. Find people who have the same problems. Learn to say “no”. Sometimes, less is more – you’ve got so many ideas floating around and such large groups – sometimes you need smaller groups and a focused, trimmed down set of ideas so that you can define software and implement it. It’s easier to read tens of emails per week than thousands.

Discussion led to code, which led to bug reports.

Mailing lists are not a bug tracker. Gforge is, but it does too much. They decided to use SVN + Trac for Ruport. Allows a casual user to subscribe to what’s happening and to contribute. It’s amazing how much good tools can affect a community and allow contributions. But what about RubyForge? Virtualy all interesting Ruby software is on RubyForge, which gives your software exposure. They used svk and cron to mirror their repository over to RubyForge.

Friction affects contribution. Explain how people can contribute bug reports, patches, etc.

Every patch is valuable. Not every patch is suitable, but the relationships you can establish are important. Patches (suitable or not) give you an idea of what people are trying to get out of your software. Still want relevant patches. What is relevant? It took them 15 months to figure it out – way to long. They came up with a roadmap and a scope definition. They didn’t just scope features, but the design as well.

We have to be careful not to accept code/features that are only for ourselves – that will never be used by anyone else. They moved some things out of the core into plugins.

Unique project identity is good. Half-way implemented features are bad for users.

Recommends the book “Producing OSS Software” by Karl Fogel, which is available for free online.

Ruport 1.0 will be released on May 15, 2007.

Sometimes, developers have to “hide” from the large community surrounding their project, simply because they don’t have time to respond to all questions and ideas. They have to make time for families, work, and for development. It’s good to get smart users involved to help answer questions.