Forum: IronRuby Dynamic Binding fails if abstract event not implemented

Hi - I've just downloaded the latest IR source from GitHub and have a
problem with what looks like a regression from v0.4.

We have an interface defining an event which is implemented by an
abstract class in C#. In Ruby, we create an implementation of the
abstract class and call only a subset of methods as we require them.
The 0.4 version played nicely and would only do the dynamic binding of
methods we required at the time we called them, however the latest
version of IR seems to try and bind the event (even though we don't
hook up to it) and can't find an implementation in ruby so it throws a
TypeLoadException citing the adder for the event does not have an
implementation.

A reproducible case is pasted below. Hoping someone would be able to
shed light on whether this is intentional, and if so what we can do to
implement the event in ruby.

***************************
using System;

namespace HelloWorldApp
{
    public interface IHelloWorld
    {
        event EventHandler SomeEvent;
    }

    public abstract class AbstractHelloWorld : IHelloWorld
    {
        public abstract event EventHandler SomeEvent;
    }
}

***************************
require "HelloWorldApp.dll"

class HelloWorlder < HelloWorldApp::AbstractHelloWorld
end

@hello_app = HelloWorlder.new #barf

***************************
D:\source\dotnet\IronRubyInteropBug>ir ruby_test.rb
mscorlib:0:in `_TermCreateClass': Method 'add_SomeEvent' in type
'IronRuby.Classes.AbstractHelloWorld$1' from assembly
'Snippets.scripting, Version=0.0.0.0, Culture=neutral,
PublicKeyToken=null' does not have an implementation.
(System::TypeLoadException)
        from mscorlib:0:in `CreateTypeNoLock'
        from mscorlib:0:in `CreateType'
        from 
c:\IronRuby\ndp\fx\src\Core\Microsoft\Scripting\Actions\DynamicMetaObjectBinder.cs:107:in
`Bind'
        from 
c:\IronRuby\ndp\fx\src\Core\Microsoft\Scripting\Actions\CallSiteBinder.cs:85:in
`BindCore'
        from ruby_test.rb:6


Any assistance appreciated - cheers!

-xerx

Definitely a bug. I've filed it under 
http://ironruby.codeplex.com/WorkItem/View.aspx?WorkItemId=1628.

Tomas

great - thanks for the follow up, Tomas.

Is there a workaround we could use in the meantime? Really keen to get
Cucumber going ;)

-Xerx

On Tue, Jun 23, 2009 at 2:49 PM, Tomas

Could you derive from AbstractHelloWorld in C# and implement the 
abstract event and then derive from this derived class in Ruby?

Tomas

Actually the AbstractHelloWorld is used as a work-around for
implementing the interface directly in ruby (see
http://ironruby.codeplex.com/WorkItem/View.aspx?WorkItemId=772), so
implementing it in C# gives us no benefit.

I did try (in our codebase, i havent tested this particular example)
removing the abstract modifier on SomeEvent in AbstractHelloWorld and
leaving everything else as abstract on the interface, and I get the
same failure for add_OnProgress on IronRuby::System::Object.

-Xerx

On Tue, Jun 23, 2009 at 4:51 PM, Tomas

I've been meaning to ask this for a while now.
Can I implement an event that is defined on an interface because 
whichever
way I try it just won't work.

public interface IHaveAnEvent { event EventHandler SomeEvent; }

class EventImplementor
  include IHaveAnEvent

  # what now? I can't find any test cases for interface to see how it 
can be
done.
end
---
Met vriendelijke groeten - Best regards - Salutations
Ivan Porto Carrero
Blog: http://flanders.co.nz
Twitter: http://twitter.com/casualjim
Author of IronRuby in Action (http://manning.com/carrero)

Ivan Porto carrero wrote:
> I've been meaning to ask this for a while now.
> Can I implement an event that is defined on an interface because 
> whichever
> way I try it just won't work.
> 
> public interface IHaveAnEvent { event EventHandler SomeEvent; }
> 
> class EventImplementor
>   include IHaveAnEvent
> 
>   # what now? I can't find any test cases for interface to see how it 
> can be
> done.
> end
> ---
> Met vriendelijke groeten - Best regards - Salutations
> Ivan Porto Carrero
> Blog: http://flanders.co.nz
> Twitter: http://twitter.com/casualjim
> Author of IronRuby in Action (http://manning.com/carrero)

I was trying to implement an interface to use OpenRasta from IronRuby 
and ran into the same thing.
Received the same error as Xerx did above, and assumed it was just a 
limitation of the language at the moment.
Would be great if we can implement the add_SomeEvent handlers at some 
point though.

For now I voted for the CodePlex issue Tomas pointed out above.