Hi team,
I’m just trying to put together some cool samples for a DLR user group
session i’m doing next week. Sadly, I can’t do MVC + IronRuby because
Preview 4 isn’t out, however I was wondering if you could provide some
technical insight into how MVC knows about IronRuby?
Does the framework host the DLR in order to make this happen? Or is it
interacting in some other way?
Also, if anyone knows any cool demos around IronRuby (apart from
silverlight integration and the actual language) please let me know 
Thanks
Ben
Yes, there’s additional C# code involved which uses the DLR hosting
interfaces.
For the sample that was shown at TechEd, code in Global.asax.cs executed
“routes.rb”. This set up handlers to point to Ruby-based controllers.
A C# RubyController class served both to delegate the request to the
Ruby-based controller and to serve as a base class for it. A set of
classes fronted by “RubyViewEngine” were used to read an .rhtml file and
execute it through IronRuby.
All of this except the code in Global.asax.cs was abstracted out into a
separate library. The only other app-specific code written in C# for
the demo was the database access code. (And this was not because we
couldn’t create models in Ruby.)
Naturally, the sample that’s made available with CTP 4 may look totally
different :).
Thanks for your reply. Does the additional code for te DLR interfaces
live inside the MVC framework?
RouteTable.Routes.LoadFromRuby(); <— This creates a runtime +
engine and executes the code (routes.rb) and adds it back to the C#
collection. I understand how this works.
Looking a bit more at the sample, RubyControllerFactory is part of the
MVC framework. This will also creates a runtime\engine for the
language and be able to pass execution to HomeController.rb similar to
how RubyRouteLoader.cs works.
Does this mean there will be a PythonControllerFactory? Why isn’t
there just a DLRControllerFactory as the actual hosting interface is
the same?
Once CTP 4 is out, I will be able to find out for myself, but if you
could say if I was on the right line that would be good 
Thanks
Ben
None of the DLR-specific stuff is inside the same assembly as the MVC
framework. It’s all in a separate library. ASP.NET MVC is extremely
flexible, so it’s possible to extend it in this way without modifying
the core sources.
This particular version of the sample is extremely Ruby-specific. There
are at least two reasons why it was written this way:
- the DLR doesn’t yet expose a “create instance” operation through its
public API, so there’s no language-independent mechanism for creating an
instance object given a class object
- IronRuby needs some work on how it exposes language features to the
DLR
I don’t know how much that will change for CTP 4, or if we’ll have
Python support by then. There seems to be considerably more interest in
the community for running Ruby in IIS than for running Python, so we’re
targeting our resources accordingly.
