Resumen
This article focuses on a layered approach to building open aspect-oriented programming systems. An open operating system is characterized by its ability to modify the semantics of existing policies and by its ability to add new policies. Systems are often implemented using the layering approach and a familiar example of such layering is network protocol stacks. In the layered approach, the system is decomposed into a number of layers. Each layer relies on the functionality and interface of the layer just below it. In operating systems the bottom layer interfaces with the hardware, the top layer provides the interface for applications. Layers provide abstraction. A layer does not need to know how the operations of the layer below it are implemented. This has a great advantage in information hiding. The layered approach facilitates the separation of aspects, components and layers and provides closure under composition rules. This closure under composition of aspects, components and layers gives the framework its desired applicability.