IronRuby on Silverlight Demo at RubyConf

John Lam recently gave the folks at RubyConf a sneak-peak to what is coming from Microsoft's commitment to Ruby running on its Dynamic Language Runtime (DLR) and of course, Silverlight.

The demonstration was different than other Silverlight demonstrations, where  instead of writing XAML markup to have the Silverlight engine render, code was written in Ruby.   Quoting John Lam:

This is one of the first (to my knowledge) examples of a code-first Silverlight 1.1 application. Most Silverlight applications that generate UIs do so by creating a XAML string that they feed to the XAML parser. When you have a language as beautiful as Ruby, it's a shame to be creating trees via strings.

XAML markup looks like this for the demo:

<Storyboard x:Name="Timeline1" TargetName="ScaleTransform1">
  <DoubleAnimationUsingKeyFrames BeginTime="00:00:00" 
      Storyboard.TargetProperty="ScaleX">
    <SplineDoubleKeyFrame KeyTime="00:00:00.0" Value="0.200"/>
    <SplineDoubleKeyFrame KeyTime="00:00:00.2" Value="0.935"/>
    <SplineDoubleKeyFrame KeyTime="00:00:00.3" Value="0.852"/>
    <SplineDoubleKeyFrame KeyTime="00:00:00.4" Value="0.935"/>
  </DoubleAnimationUsingKeyFrames>
  <DoubleAnimationUsingKeyFrames BeginTime="00:00:00" 
      Storyboard.TargetProperty="ScaleY">
    <SplineDoubleKeyFrame KeyTime="00:00:00.0" Value="0.200"/>
    <SplineDoubleKeyFrame KeyTime="00:00:00.2" Value="0.935"/>
    <SplineDoubleKeyFrame KeyTime="00:00:00.3" Value="0.852"/>
    <SplineDoubleKeyFrame KeyTime="00:00:00.4" Value="0.935"/>
  </DoubleAnimationUsingKeyFrames>
</Storyboard>

Microsoft has committed to running dynamic language on the DLR and with that, they are developing IronRuby on the .NET CLR which is a full implementation of the Ruby programming language.

A goal of writing code for the DLR is to be able to write native code and not have to hand-code XAML.  This would avoid the XAML above and let developers write Ruby like this:

class BounceAnimation < AnimationBase
  def initialize(scale_transform_element)
    @obj = Wpf.build(Storyboard, :name => random_name,
        :target_name => scale_transform_element) {

      add(DoubleAnimationUsingKeyFrames, :begin_time=>'00:00:00',
        :target_property => "ScaleX") {

        add(SplineDoubleKeyFrame, :key_time => '00:00:00.0', :value => 0.200)
        add(SplineDoubleKeyFrame, :key_time => '00:00:00.2', :value => 0.935)
        add(SplineDoubleKeyFrame, :key_time => '00:00:00.3', :value => 0.852)
        add(SplineDoubleKeyFrame, :key_time => '00:00:00.4', :value => 0.935)
      }

      add(DoubleAnimationUsingKeyFrames, :begin_time=>'00:00:00',
        :target_property => "ScaleY") {

        add(SplineDoubleKeyFrame, :key_time => '00:00:00.0', :value => 0.200)
        add(SplineDoubleKeyFrame, :key_time => '00:00:00.2', :value => 0.935)
        add(SplineDoubleKeyFrame, :key_time => '00:00:00.3', :value => 0.852)
        add(SplineDoubleKeyFrame, :key_time => '00:00:00.4', :value => 0.935)
      }
    }
  end
end

The ability to write Ruby is easier and more intuitive than writing XAML and easier to express intent.  Although these features were shown during the demo, the bits will not be available until the next CTP of Silverlight 1.1 where developers will be able to run IronRuby in the browser. 

More information about IronRuby can be found on the IronRuby web site and the source code from the demo is available from John Lam's blog.