Announcing The Microsoft Roslyn CTP

The Roslyn team has announced general availability of the Roslyn CTP!

The official launch is at, and there were a number of blogs to publicize the availability broadly (soma, ericli, vsteam, vbteam, c#faq) and across twitter.

This release marks a significant step to the new way of thinking of compilers, and the agility that is now possible with language innovation, IDE tooling, and powering the ecosystem. The C# and VB compilers are no longer black boxes – something we put source text into, do some magic on, and get an assembly out.  All that rich information about code is no longer thrown away, but is now exposed as a full-fidelity object model that can be easily consumed by all.  In addition, it was released a preview of the first-ever Interactive window for C# that contains full IDE support – including IntelliSense and even automatically detecting missing using directives.

How to get started:

  • Download the CTP.  The CTP installs on Visual Studio 2010 SP1 and can be safely installed side-by-side with Visual Studio 11.
  • Go to Start -> All Programs ->  Microsoft Codename Roslyn CTP -> Getting Started to launch the entry point into all the documentation, samples, and tools.
  • Read the Roslyn Project Overview for a good overview of the project.
  • Learn from the rich samples included (paste as C#/VB, refactorings, code analysis, and code generation tools).
  • Run the walkthroughs to learn about the Compiler APIs, the Services API, or using the Interactive window.
  • For those of you that aren’t extension writers, download the CTP to try out the Interactive window and use the Copy Paste C#/VB extensions that were built to help with your daily work now!

The release includes the following features:

  • Visual Studio Project Templates
    These project templates help you get started using the Roslyn APIs and building new Visual Studio extensions using the C# or VB APIs.
  • Reference Assemblies
    The Roslyn assemblies can be added to projects via the Add Reference dialog.
  • Interactive Window
    A new tool window called C# Interactive is available in Visual Studio by invoking View -> Other Windows -> C# Interactive from the menu. You can explore by either executing snippets of code in the C# Interactive tool window, or cumulatively building up execution context as you experiment.
  • Script File Editing Support
    C# Script (.csx) files allow top-level statements much like the C# Interactive window. You can create a new C# Script file by invoking File -> New File -> Script -> Visual C# Script from the Visual Studio menu. In addition to typing directly into the tool window, you can also select code in C# and C# Script (.csx) files and invoke "Execute in Interactive" or "Copy to Interactive" from the context menu. C# Script editing features like IntelliSense are powered by the Roslyn Language Service.

Please keep in mind that this is only a technology preview, and it’s not done yet! The primary goal of this CTP is to gather feedback on the public APIs and give an early look at the Interactive window feature. The shape of the APIs are in a fairly stable state, especially the Compiler ones, but there are still a set of known limitations and only a subset of the C# and Visual Basic languages are implemented in the current release.  For a full list of non-implemented language features, see here. The Interactive window is only available for C# at this time, but VB is following shortly.

The Roslyn team looks forward to hearing your feedback on the forums e through Connect.