Towards Rigorously Faking Bidirectional Model Transformations

Bidirectional model transformations (bx) are mechanisms for automatically restoring consistency between multiple concurrently modified models. They are, however, challenging to implement; many model transformation languages not supporting them at all. In this paper, we propose an approach for automatically obtaining the consistency guarantees of bx without the complexities of a bx language. First, we show how to “fake” true bidirectionality using pairs of unidirectional transformations and inter-model consistency constraints in Epsilon. Then, we propose to automatically verify that these transformations are consistency preserving—thus indistinguishable from true bx—by defining translations to graph rewrite rules and nested conditions, and leveraging recent proof calculi for graph transformation verification.