Domain-specific languages and program generation with meta-AspectJ

Abstract

Meta-AspectJ (MAJ) is a language for generating AspectJ programs using code templates. MAJ itself is an extension of Java, so users can interleave arbitrary Java code with AspectJ code templates. MAJ is a structured meta-programming tool: a well-typed generator implies a syntactically correct generated program. MAJ promotes a methodology that combines aspect-oriented and generative programming. A valuable application is in implementing small domain-specific language extensions as generators using unobtrusive annotations for syntax extension and AspectJ as a back-end. The advantages of this approach are twofold. First, the generator integrates into an existing software application much as a regular API or library, instead of as a language extension. Second, a mature language implementation is easy to achieve with little effort since AspectJ takes care of the low-level issues of interfacing with the base Java language.In addition to its practical value, MAJ offers valuable insights to meta-programming tool designers. It is a mature meta-programming tool for AspectJ (and, by extension, Java): a lot of emphasis has been placed on context-sensitive parsing and error-reporting. As a result, MAJ minimizes the number of meta-programming (quote/unquote) operators and uses type inference to reduce the need to remember type names for syntactic entities.

Interactive Disambiguation of Meta Programs with Concrete Object Syntax

“…These cases particularly arise when combining the technique with type inference, as seen with Meta-AspectJ [8], or when forgoing quoting symbols that distinguish between the meta and the object language, as observed by Vinju [13]. Both works propose heuristics as a solution in these cases.…”

“…In turn, quotations can include anti-quotations that escape from the object language code in order to include variables or expressions from the meta language. As an example, Figure 2 shows a Stratego [4] Grammar composition Some meta-programming systems, such as Jak [3] and MetaAspectJ [8], have been specifically designed for a fixed object language. These systems use a carefully handcrafted grammar or parser for the combined meta and object language.…”

Integrating legacy systems with MDE

“…In this trend of AspectJ generation, Meta-AspectJ [12] and XAspects [18], which advocate the use of AspectJ as a back-end language for aspect orientation, are similar with our approach. Nevertheless, the main goal is different.…”

Reusable software documentation with phrase annotations

“…The phrase annotations from our approach can be then reused in aspect-oriented programming [11,12] to reduce pointcut fragility, the design annotations can be used to preserve design patterns in the code [13] or to support using design patterns [14] by metaprogramming techniques. Annotations are also used as an input for many generators [15,16]. In some cases semantic and design annotations can be used to generate even program artifacts, not merely the documentation.…”