One of the most significant changes in this release is the removal of Microsoft.Scripting.Vestigial. Previously this DLL was a combination of both IronPython support code as well as portions of the DLR. With Alpha 2 Microsoft.Scripting.dll contains all portions of the DLR and IronPython.dll contains the IronPython implementation which builds upon the DLR. This should help consumers of the DLR to better understand the public surface area. Being early in the product cycle this surface area may still change significantly but there are now bright lines between what DLR code is and what IronPython code is.

The DLR also continues to be expanded and improved. The DLR AST has been improved with support for more static constructs such as simple exception handling constructors and better variable support. The DLR AST factory methods have also been moved to a static Ast class to enable easier construction of ASTs. There have also been some additional convenience methods added to various nodes to make construction even easier still. Finally the DLR also has been improved to support an arbitrary number of arguments inside a DynamicSite which helps to enable calling all functions in an optimized manner.