Infrastructure for domain-specific aspect languages: the relax case study

Domain-specific aspect languages (DSALs) bring the well-known advantages of domain specificity to the level of aspect code. However, DSALs incur the significant cost of implementing or extending a language processor or weaver. Furthermore, this weaver typically operates blindly, making detection of interactions with aspects written in other languages impossible. This raises the necessity of an appropriate infrastructure for DSALs. The case study we present here illustrates how the reflex kernel for multi-language AOP addresses these issues, by considering the implementation of a DSAL for advanced transaction management, KALA. We first detail the implementation of KALA in reflex, called relax, illustrating the ease of implementation of runtime semantics, syntax, and language translation. We then show a straightforward and modular extension to KALA at all these levels, and demonstrate how reflex helps in dealing with interactions between KALA and another DSAL for concurrency management. These invaluable assets enable faster development of DSALs as well as their ability to coexist within one application, thereby removing the most important impediments to their re-emergence in the aspect community.