The 2nd day of RubyWorld Conference 2009 (Afternoon)

Some sessions delayed 15 minutes because of projector trouble.

I attended these sessions:

• Ruby Interpreter: The Current Status and Future
  
  • speaker: Koichi Sasada
  • Please migrate to Ruby 1.9
    • multi functions and high performance
    • Survey the migration point: e.g. C extentions and M17N
  • Many Ruby implementations
    • Ruby 1.8
    • Ruby 1.9
    • JRuby
    • IronRuby
    • Rubinius
    • MagLev
    • smallruby
    • Cardinal
  • Ruby 1.8
    • The most stable Ruby currently
      • 1.8 trunk: maintained by musha
      • 1.8.7: maintained by musha
      • 1.8.6: maintained by EngineYard
    • Used in Ruby on Rails
    • Never change drastically
    • Migration path to the Ruby 1.9
    • in Ruby 1.8.8, never raises syyntax error by the syntax of Ruby 1.9
    • Ruby 1.8.9 will never be released
  • Ruby 1.9 features
    • M17N
    • Ordered hash
    • New hash notation with Symbol keys only:
      {a: 1, b: 2, c: 3}
    • New lambda notation ->
    • Block parameters
    • Changing scope of parameters in block
    • include RubyGems
    • include Rake
    • Fiber
  • Ruby 1.9 performance
    • speed: improved little better
      • By introducing the new VM, many functions speed up.
      • Few functions speed down, but Rails often uses them.
    • memory footprint: improved muchj better
  • Reduce dependency on Matz
    • start to establish the release manager
    • start to establish the coverage tester
    • start to track tickets with Redmine
  • Ruby 1.9.2
    • improve the stability
    • improve the working with RubySpec
    • ready to run Ruby on Rails
  • Stabilization
    • Documentation
    • Portability
      • From Ruby 1.9, we have clarified the platforms to support and not to support.
      • And we would like to increase supporting platforms.
  • Researching now
    • high performance
    • embedded system
    • multi VM
    • more functions
• IronRuby and Software, Service
  
  • speaker: Kazuyoshi Korosue
  • What can Microsoft do for Rubyists to be happy?
  • Assistance development of IronRuby
    • Suppport IronRuby community
    • Hiring core members
  • Simple platform access
  • Decide scopes of standardization and compatibility
    • Separating language specification from implementation
  • DLR
    • IronPython, IronRuby, ECMAScript and so on
    • Plans to be standard feature in .NET 4.0
    • Use .NET from IronRuby
    • Use IronRuby from C#
    • Interoperability between dynamic languages
  • Silverlight
    • I think it's weak point of Ruby to implement rich clients.
    • In Silverlight, we can implement it with only Ruby and XAML.
    • Cross-platform: Win, Mac, Linux
    • Cross-browser: IE, Firefox, Safari
    • e.g. Super fruit world
      • Social application in mixi(most popular SNS in Japan)
      • front-end: IronRuby and Silverlight
      • back-end: Some applications include Ruby on Rails
  • Silverlight DEMO

  Q from attendee	Can IronRuby operate Word or Excel?
  A from speaker	It's easy for the user from C# backgrounds, but difficult for the user from Ruby backgrounds.
  Q from attendee	What's unique benefit of IronRuby?
  A from speaker	Interoperating with .NET and related technologies.
  Q from me	At past, I read the article about the project simplifying from XAML to Ruby's internal DSL. How about it now?
  A from speaker	We recommand XAML. And I don't know much about that project. So I will survey.

• JRuby: Bringing Ruby to the Java World
  
  • speaker: Thomas Enebo
  • speaker: Charles Nutter
  • We have been developing JRuby as a full-time job for 3 years.
  • We were hired at Sun until nowadays.
  • Recently, we join to Engine Yard.
  • We have also been using Java for 12 years.
  • JRuby
    • A Ruby interpreter running on JVM
    • Support native thread
    • Not support C Extentions
      • Some libraries in common usage are ported for JRuby like YAML library.
      • We will use FFI eventually.
    • To access Java libraries
      • Java is Everywhere
      • Java is mature
  • JRuby Codebase
    • 3 full-time engineers
    • Large number of community members
  • JRuby DEMO
  • Android
    • Runs JRuby very well = Ruby as a mobile language
  • jirb on Android DEMO
  • ActiveHibernate DEMO
    • Load Hibernate XML file.
    • class Event
        extend Hibernate::Model;
        hibernate_attr :id => :long, :title => :string, :date => :date
        hibernate!
      end
    • tx(&block) ... Block to do with transaction
  • Google App Engine
    • Deploying JRuby and Rack
    • Scaling automatically
    • To access Google resources
  • Sites working with JRuby on Rails
    • Kenai
    • auktionskompaniet.com
    • Pons.eu
    • Trisano
    • Fuel system of Gardermoen airport

  Q from attendee	Do you have a plan to release jirb on Android?
  A from speaker	Yes. We are going to release it as free. And also release source codes. What should we release in the next week?
  Q from attendee	What is most difficult ever on developing JRuby?
  A from speaker	Porting C Extentions to JRuby libraries.
  Q from attendee	In current demonstaraion, You use the file called "Hibernate XML". What is this?
  A from speaker	It's only just Hibernate's XML file. We plan to simplify as internal DSL.

• Applying compiler technology to Ruby
  
  • speaker: Evan Phoenix
  • Reasons that Ruby is wonderful also make Ruby slow.
    • A new code is interpreted each time.
    • Dynamic typing
    • late-bound method call
  • Can I learn from the example of other languages?
    • Smalltalk
    • Self
    • Java(Hotspot)
  • Codes compiled are faster than codes interpreted.
  • It's almost impossible to figure out statically.
  • Type profile
  • Code generation with JIT compiler
  • Dynamic dispatch is possible, but not always.
  • Method inlining: The method called frequently is inlined.
  • In Rubinius, JIT compiler is built with LLVM.
  • Type profiling with LLVM and Inline Cache
  • A benchmark of Rubinius is faster than Ruby 1.8.
  • A benchmark of Rubinius with JIT-on is faster than Ruby 1.9.
  • A benchmark using Hash of Rubinius is slower than Ruby 1.8 and Ruby 1.9.
  • A benchmark using Tak of both Rubinius with JIT-on and Ruby 1.9 is faster than others.
• Closing
  
  • speech: Hiroshi Inoue

N.B. These summaries may be imprecise.

Sorry for my vocabulary and knowledge are so poor to understand this Evan Phoenix's session.

At last, in closing, Numbers of attendees are announced:
The 1st day: 590
The 2nd day: 502