Combining a Declarative Language and an Imperative Language for Bidirectional Incremental Model Transformations

Bidirectional incremental model transformations are crucial for supporting round-trip engineering in model-driven software development. A variety of domain-specific languages (DSLs) have been proposed for the declarative specification of bidirectional transformations. Unfortunately, previous proposals fail to provide the expressiveness required for solving practically relevant bidirectional transformation problems. To address this shortcoming, we propose a layered approach: On the declarative level, a bidirectional transformation is specified concisely in a small and light-weight external DSL. From this specification, code is generarated into an object-oriented framework, on top of which the behavior of the transformation may be complemented and adapted in an imperative internal DSL. An evaluation with the help of a well-known transformation case demonstrates that this layered hybrid approach is both concise and expressive, and also scalable.