An In-Depth Look at ALIA4J.

Abstract

New programming languages supporting advanced modularization mechanisms are often implemented as transformations to the imperative intermediate representation of an already established language. But while their core constructs largely overlap in semantics, re-using the corresponding transformations requires re-using their syntax as well; this is limiting. In the ALIA4J approach, we identified dispatching as fundamental to most modularization mechanisms and provide a meta-model of dispatching as a rich, extensible intermediate language. Based on this meta-model, one can modularly implement the semantics of dispatchingrelated constructs. From said constructs a single execution model can then be derived which facilitates interpretation, bytecode generation, and even optimized machine-code generation. We show the suitability of our approach by mapping five popular languages to this meta-model and find that most of their constructs are shared across multiple languages. We furthermore present implementations of the three different execution strategies together with a generic visual debugger available to any ALIA4J-based language implementation. Intertwined with this paper is a tutorial-style running example that illustrates our approach.

The potential of omniscient debugging for aspect-oriented programming languages

“…In our prior work [5], we classified AOP as one kind of advanceddispatching (AD) languages and we have shown that AO concepts can be perfectly matched to the AD domain. Our work is carried out based on a framework for executing AD programs.…”

Defusing debugging scandal

“…Our current implementation of the debugger is based on the ALIA4J NOIRIn execution environment [10], which is implemented as a Java 6 agent intercepting the execution of the base program to perform the dispatch. NOIRIn can integrate with any standard Java 6 JVM, therefore our approach does not require using a custom virtual machine.…”

“…In this work, we use join point instead, because join points are modelled as firstclass objects in our execution environment NOIRIn [10]. Besides, we want to distinguish our work from existing trace-based debuggers.…”

“…The trace model is implemented as an extension to NOIRIn [10], where AD concepts are modelled and run as first-class objects. We used three dedicated approaches for collecting runtime information defined in the trace model.…”

“…developed based on a ALIA4J framework [10], which models AO-specific concepts as first-class values. It also records and present information in AD-specific terms.…”