.NET Compiler Platform

.NET Compiler Platform, better known by its codename "Roslyn", is a set of open-source compilers and code analysis APIs for C# and Visual Basic .NET languages from Microsoft.

The project notably includes self-hosting versions of the C# and VB.NET compilers – compilers written in the languages themselves. The compilers are available via the traditional command-line programs but also as APIs available natively from within .NET code. Roslyn exposes modules for syntactic (lexical) analysis of code, semantic analysis, dynamic compilation to CIL, and code emission.

Even though the final and official name of the component is ".NET Compiler Platform", it is widely referred to by its code name, "Roslyn".

The code name "Roslyn" was first written by Eric Lippert (a former Microsoft worker) in a post that he published to hire developers for a new project. He first said that the origin of the name was because of Roslyn, Washington, but later in the post he speaks ironically about the northern exposure of its office. The city of Roslyn was one of the places where this television series was filmed.

The most notable primary features of Roslyn include:

Microsoft made a community technology preview (CTP) available for public download in October 2011. It installed as an extension to Visual Studio 2010 SP1.

The CTP was updated on September 2012 to include many updates to the Roslyn APIs introduced in the June 2012 and October 2011 CTPs, including . While the June 2012 CTP API is complete for the compilers, not all features were implemented for the C# and VB.NET languages.

At the Build 2014 conference in San Francisco April 2014, Microsoft made the "Roslyn" project open-source and released a preview of the language integration for Visual Studio 2013. As of April 3, 2014, Roslyn is under the Apache License 2.0. The project was effectively transferred under the stewardship of the newly founded .NET Foundation. At the same conference, Xamarin announced that they are working on integrating the new compilers and tools in Xamarin Studio.

...
Wikipedia