General-purpose Aspect Languages Research Articles

Language Oriented Modularity: From Theory to Practice

Language-oriented modularity (LOM) is a methodology that complements language-oriented programming (LOP) in providing on-demand language abstraction solutions during software development. It involves the implementation and immediate utilization of domain-specific languages (DSLs) that are also aspect-oriented (DSALs). However, while DSL development is affordable thanks to modern language workbenches, DSAL development lacks similar tool support. Consequently, LOM is often impractical and underutilized. The challenge we address is making the complexity of DSAL implementation comparable to that of DSLs and the effectiveness of programming with DSALs comparable to that of general-purpose aspect languages (GPALs). Today, despite being essentially both domain-specific and aspect-oriented, DSALs seem to be second-class. Aspect development tools (e.g., AJDT) do not work on DSAL code. DSL development tools like language workbenches (e.g., Spoofax) neither deal with the backend weaving nor handle the composition of DSALs. DSAL composition frameworks (e.g., Awesome) do not provide frontend development tools. DSAL code transformation approaches (e.g., XAspects) do not preserve the semantics of DSAL programs in the presence of other aspect languages. We extend AspectJ with a small set of annotations and interfaces that allows DSAL designers to define a semantic-preserving transformation to AspectJ and interface with AspectJ tools. Our transformation approach enables the use of standard language workbench to implement DSALs and use of standard aspect development tools to program with those DSALs. As a result, DSALs regain first-class status with respect to both DSLs and aspect languages. This, on the one hand, lowers the cost of developing DSALs to the level of DSLs and, on the other hand, raises the effectiveness of using a DSAL to the level of a GPAL. Consequently, LOM becomes cost-effective compared to the LOP baseline. We modified the ajc compiler to support our approach. Using two different language workbenches (Spoofax and Xtext) we then implemented several DSALs. AspectJ was supported out-of-the-box. We implemented Cool to demonstrate that the non-trivial composition of AspectJ and Cool can be accommodated using our approach. We applied LOM to crosscutting concerns in two open source projects (oVirt and muCommander), implementing in the process application-specific DSALs, thus providing a sense of the decrease in the cost of developing composable DSALs and the increase in the effectiveness of programming with them. Crosscutting concerns remain a problem in modern real-world projects (e.g., as observed in oVirt). DSALs are often the right tool for addressing these concerns. Our work makes LOM practical, thus facilitating use of DSAL solutions in the software development process.

KALA: Kernel aspect language for advanced transactions

Transaction management is a known crosscutting concern. Previous research has been conducted to express this concern as an aspect. However, such work has used general-purpose aspect languages which lack a formal foundation, and most importantly are unable to express advanced models of transaction management. In this paper, we propose a domain-specific aspect language for advanced transaction management, called KALA, that overcomes these limitations. First, KALA is based on a recognized formalism for the domain of advanced transaction management, called ACTA. Second, as a consequence of being based on the ACTA formalism, KALA covers a wide variety of models for transaction management. Finally, being a domain-specific aspect language, KALA allows programmers to express their needs at a higher level of abstraction than what is achieved with general-purpose aspect languages. This paper reports on the design of KALA and its implementation over Java, based on the Reflex AOP kernel for domain-specific aspect languages.

La réflexion comportementale partielle comme infrastructure de programmation par aspects. Etude du cas des coupes dynamiques

The relationship between reflection and aspect-oriented programming is still under exploration. This paper reports on an experiment to support a widely-accepted, general-purpose aspect language mechanism - Aspect J's dynamic crosscutting -, with a model of partial behavioral reflection. We present a first approach to such a mapping, identify some extensions that can improve the effectiveness of the mapping, and validate our proposal through a revisited mapping. These extensions have been integrated into our Java and AOP reflective platform, Reflex.