A calculus of untyped aspect-oriented programs

Abstract

Aspects have emerged as a powerful tool in the design and development of systems, allowing for the encapsulation of program transformations. The dynamic semantics of aspects is typically specified by appealing to an underlying object-oriented language via a compiler transformation known as weaving. This treatment is unsatisfactory for several reasons. Firstly, this semantics violates basic modularity principles of object-oriented programming. Secondly, the converse translation from object-oriented programs into an aspect language has a simple canonical flavor. Taken together, these observations suggest that aspects are worthy of study as primitive computational abstractions in their own right. In this paper, we describe an aspect calculus and its operational semantics. The calculus is rich enough to encompass many of the features of extant aspect-oriented frameworks that do not involve reflection. The independent description of the dynamic semantics of aspects enables us to specify the correctness of a weaving algorithm. We formalize weaving as a translation from the aspect calculus to a class-based object calculus, and prove its soundness. © Springer-Verlag Berlin Heidelberg 2003.