One thing sadly lacking in the world of .NET is a package manager that can take the pain out of both maintaining and installing .NET packages. Notable examples of existing package managers on other platforms include Maven and App-Get. The horn open source project has been created with the goal of creating such a package manager. Package metaphors are described in separate DSL files that contain build metadata and dependency references. The DSL files live in a directory tree that models the dependency structure. BOO was chosen for the internal DSL, firstly because it is a CLR implementation and secondly for it's built in DSL support and lastly because of Iron Ruby's infancy.