How to write debugger?

For code completion SharpDevelop uses its own parsers for C# and VB.NET. They were generated using a grammar description and a modified version of the Coco/R compiler generator of the University of Linz. The source code contains this generator. For Boo, the parser from the Boo compiler is used, but resolving the type of expressions and type inference is done with custom code that supports lazy evaluation of the types. SharpDevelop 1.1 can import projects written with Visual Studio, SharpDevelop 2.0 can open and edit them directly. It also can translate whole projects from VB.NET to C# and vice-versa. SharpDevelop 1.1 cannot however be used to create asp.net web projects, which Visual Studio can, or rather it has the option in the file menu but it has not been completed yet. The company is currently looking for coders to help support this feature