The ELC Community Blog

A knowledge exchange on Ruby on Rails and Agile Development

IronRuby prealpha

by stevend on September 10, 2007

So let's start with something simple... how to get iron ruby installed. After searching around for bit, I found this binary on John Lam's Blog:

http://iunknown.typepad.com/IronRuby-Pre-Alpha1.zip

c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\msbuild.exe /p:Configuration=Release /t:Rebuild IronRuby.sln

This worked perfectly, which got me very excited! I decided run to try out "rbx" next (the Microsoft version of IRB):

   1  <pre>Build succeeded.
   2      0 Warning(s)
   3      0 Error(s)
   4  
   5  Time Elapsed 00:00:08.69
   6  
   7  PROMPT> cd bin\Release
   8  PROMPT> rbx.exe
   9  IronRuby Pre-Alpha (1.0.0.0) on .NET 2.0.50727.832
  10  Copyright (c) Microsoft Corporation. All rights reserved.
  11  >>>
  12  </pre>

So far so good... but what can this ruby console really do? Let's push our luck!

   1  <pre>>>> 2+2
   2  => 4
   3  >>> "hello" + "world"
   4  => "helloworld"
   5  >>> ["hello", "world"].join(" ")
   6  => "hello world"
   7  >>> ["hello", "world"].each do |elem|
   8  ... puts elem
   9  ... end
  10  hello
  11  world
  12  => [hello, world]
  13  </pre>

Wow! That worked exactly as I expected. Now let's watch things go downhill:

   1  <pre>>>> h = {}
   2  Ruby.Builtins.NotImplementedError: Exception of type 'Ruby.Builtins.NotImplementedError' was thrown.
   3  >>> eval("puts 'hello'")
   4  System.MissingMethodException: undefined local variable or method `eval' for #<object:0000002b>:Object
   5  >>> "  b  ".strip
   6  System.MissingMethodException: undefined local variable or method `strip' for   b  :MutableString
   7  
   8  </object:0000002b></pre>

Class definitions are open:

   1  >>> class TestKlass
   2  ...     def bob
   3  ...             puts "bob"
   4  ...     end
   5  ...     def joe
   6  ...             puts "joe"
   7  ...     end
   8  ... end
   9  => nil
  10  >>> class TestKlass
  11  ... def bob
  12  ... puts "Fred"
  13  ... end
  14  ... end
  15  => nil
  16  >>> TestKlass.new.bob
  17  Fred
  18  => nil
  19  >>> TestKlass.new.joe
  20  joe
  21  => nil

The source contains two major divisions, Microsoft.Scripting and Ruby. Inside Ruby, you can see the progress the project has made so far in converting ruby objects and constructs to be available in IronRuby.

Finally, let's examine what we can do by taking advantage of the common language runtime (CLR) to access libraries in another language

   1  <pre>>>> 
   2  >>> require 'System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089'
   3  => true
   4  >>> require "System.Windows.Forms"
   5  => true
   6  >>> System::Windows::Forms::MessageBox.show "hello"
   7  => #<dialogresult:0000002c>   # messagebox showed up!
   8  >>> System::Net::WebRequest.Create("http://www.google.com/")
   9  System.MissingMethodException: No overload of method `Create' matches the specified argument types
  10     at _stub_##22(Object[] , DynamicSite`3 , CodeContext , Object , MutableString )
  11     at Microsoft.Scripting.Actions.DynamicSite`3.UpdateBindingAndInvoke(CodeContext context, T0 arg0, T1 arg1)
  12  </dialogresult:0000002c></pre>

Some of you are probably wondering why the 2nd to last line worked but the last line doesn't. They are both static methods of imported libraries which take a single string argument. If someone has looked through the DLR scripting code and knows, post a comment. Thanks!

Additional resources (where some of this information came from):

• John Lam's Blog - The creator IronRuby
• Scott Gunthrie's Blog - Good example of using IronRuby with the new windows UI framework in .NET 3.0