Based on Roslyn C# compiler (as a service) written in C#,.
open source ScriptCS will apparently be included to VisualStudio,
along with Script VB and Script FS (F#), and node.js that is already there.
C# compiler API was always available as a part of .NET,
but calling it required Reflection and was not simple.
This could be useful for making plugins and "embedded" DSLs.