Efficient language implementation with ALIA4J and EMFText: forum demonstration

Developing extensions to general-purpose langauges or domain-specific languages with support for new kinds of abstractions is an ongoing trend. Modern language workbenches, such as EMFText of Xtext, support this trend and facilitate implementing langauges in terms of transformations from the new language into an established (intermediate) language. Often, however, the implementation of one element in the source language becomes scattered and tangled in the target language, which makes transformations complex. Furthermore, even though many languages share core concepts, current approaches do not support sharing transformations that implement their semantics; the only possibility of re-using transformations from a language is to extend it syntactically. We have identified dispatching as fundamental to most abstraction mechanisms. With the ALIA4J approach, we provide a meta-model of dispatching to act as rich and extensible intermediate language that allows more direct transformation. The semantics of core language concepts can be modularly implemented as extension of the meta-model. For the execution of the intermediate language, we provide both platform-independent and platform-dependent Java Virtual Machine extensions, the latter of which even allows the modular implementation of machine code optimizations. In this demo, participants get an overview of advanced dispatching and the ALIA4J approach. By the example of a language for text-based adventure games, they will see the usage of ALIA4J as back-end for a language developed in EMFText. Finally, the implementation of new atomic language concepts and their optimization is demonstrated.