Arguably, the biggest feature of C# 4.0 is the new dynamic type. And it’ll be great…when it ships. In the meantime, some of us what to build hybrid C# and IronPython applications today, such as my Pygments for Windows Live Writer plugin.

Pygments is a syntax highlighter, written in Python, with support for over one hundred languages. With the exception of a couple of bugs in our importer (discussed here) it works great with IronPython. It’s also extensible, so I was able to easily build a custom formatter to output exactly the HTML I want inserted in my blog posts. So it made perfect sense to use Pygments as the basis of a Windows Live Writer plugin.

As great a tool as Windows Live Writer is, it’s developers haven’t exactly seen the light when it comes to dynamic languages. If you want to create a custom Content Source for Windows Live Writer, you have to generate a compiled on-disk assembly with a static type and custom attributes. Not exactly IronPython’s forte, if you know what I mean. I did try and build a pure IronPython solution, but eventually gave up. So I ended up building a hybrid solution. The front end of the plugin as well as the UI elements are written in C# while the syntax highlighter engine is written in IronPython. And since this is running on the current .NET framework, I didn’t have the new fangled C# 4.0 dynamic type to help me.

Over the next couple of blog posts, I want to highlight a few aspects how I built this plugin, including compiling Python packages into assemblies and invoking Python code from C# 3.0 and earlier. If you want to look for your self, the source is up on GitHub.

I mentioned yesterday that it looked like a new release of AgDLR was eminent and sure enough here it is. There are some really cool new features including Silverlight 3 Transparent Platform Extension support, In-Browser REPL and In-Browser testing of Silverlight apps. As with IronRuby 0.3, Jimmy has the a summary of the new AgDLR release.

One feature of the new release I did want to highlight was XapHttpHandler because I’m the one who wrote it! 😄

The Silverlight versions of IronPython and IronRuby ship with a tool called Chiron that provides a REPL-esque experience for building dynamic language Silverlight apps. John Lam had a good write-up on Chiron when we first released it last year, but basically the idea is that Chiron is a local web server that will auto-generate a Silverlight XAP from a directory of Python and/or Ruby files on demand. For example, if your HTML page requests a Silverlight app named app.xap, Chiron automatically creates the app.xap file from the files in the app directory. This lets you simply edit your Python and/or Ruby files directly then refresh your browser to get the new version without needing an explicit build step.

The problem is that, unlike IIS and the ASP.NET Development Server, Chiron doesn’t integrate with ASP.NET. So it’s fine for building Silverlight apps that stand alone or talk to 3rd party services. But if you want to build a Silverlight app that talks back to it’s ASP.NET host, you’re out of luck. That’s where XapHttpHandler comes in. XapHttpHandler does the same exact on-demand XAP packaging for dynamic language Silverlight applications that Chiron does, but it’s implemented as an IHttpHandler so it plugs into the standard ASP.NET pipeline. All you have to do is put the Chiron.exe in your web application’s bin directory and add XapHttpHandler to your web.config like so:

<configuration>
  <!--remaining web.config content ommitted for clarity-->
  <system.web>
    <httpHandlers>
      <add verb="*" path="*.xap" validate="false"
           type="Chiron.XapHttpHandler,Chiron"/>
    </httpHandlers>
  <system.web>
</configuration>

The new AgDLR drop includes a sample website that shows XapHttpHandler in action.

Quick note of caution: by design, XapHttpHandler does not cache the XAP file – it’s generated anew on every request. So I would highly recommend against using XapHttpHandler on a production web server. You’re much better off using Chiron to build a physical XAP file that you then deploy to your production web server.

IronPython 2.0 shipped about a month ago, but we’re still chugging along with our post 2.0 work. We’ve shipped seven source code releases since we shipped 2.0 and we should be back to our normal schedule of updating the source 2-3 times a week schedule by next week. Given how often we ship source, we’re thinking of extending the the time between binary drops. Binary releases have to be signed and there’s a fairly arduous process we have to go thru in order to get each binary release out the door.

However, there’s something nice and convenient about downloading a pre-compiled binary release. So I spent my Christmas vacation building a script to download and build IronPython nightly builds. Once built, I compress the binaries and upload them to Azure blob storage. Finally, I built a very simple cloud app for users to view and download available nightly builds. As an extra benefit, I’m also providing nightly builds of the DLR.

Please note, these are *NOT* official Microsoft releases of IronPython and/or DLR. They aren’t signed and they haven’t gone through the aforementioned release process. I’m just downloading the public source, building it with the publicly available tools, then making them available on a a publicly accessible website.

The website for the IronPython (and DLR) nightly builds is http://nightlybuilds.cloudapp.net.

As usual, I welcome any feedback. Is having prebuilt unsigned binaries of IPy releases useful? Do you want IronRuby binaries as well? What about social features (rating releases, comments, etc)? Please let me know what you think.

I just hit the MSDN home page, and what should I see?

It’s cool to see JasonZ, aka my group’s general manager, blogging about our product.

I also fired up Visual Studio, and IronPython is the top headline there too:

Not sure why the news is dated September 18th, but hey it’s really cool to see IronPython (not to mention the DLR, with the second headline) getting this kind of visibility.

Tomorrow may be Thanksgiving, but the Microsoft DevDiv dynamic language teams are trying to make it feel like Christmas with three separate pre-holiday releases.

1. IronPython 2.0 RC2 
   We were really hoping to only have one release candidate, but we ended up with a couple of significant bugs that we couldn’t push off to 2.0.1. With December holidays coming soon, RC2 has a pretty small window before we declare RTM so now is the time to download the release and try your code out.
2. IronRuby 1.0 Alpha 2 
   There’s been zero blog traffic on this, just a notice on the IronRuby mailing list. As per said notice, “Notable features” include “the inclusion of iirb.bat, igem.bat, irails.bat, irake.bat”.
3. New DLR CodePlex Project
   The DLR source has been available as part of IronPython for over a year but now they have their own home on CodePlex. Check out the Release Notes for an overview, reads some Docs and Specs or just download their initial v0.9 beta. Their v0.9 beta is synced with IPy 2.0 RC2 (and their v0.9 final will sync with IPy 2.0 RTM) but it also includes synced versions of IronRuby and ToyScript in both source and binaries. Plus, Sesh has promised “weekly code drops”. Finally, unlike IronPython and IronRuby, DLR is using the discussion section of their CodePlex site – I’m eager to see how well the new-ish discussion/mailing list integration works.

So there you go, new versions of IronPython and IronRuby plus a whole new DLR CodePlex project to boot. Enjoy.