Towards Functional Model Transformations with OCL

Several model transformation approaches such as QVT and ATL use OCL as expression language for its model-querying capabilities. However, they need to add specific and incompatible syntactic constructs for pattern matching as well as model element creation and mutation. In this paper, we present an exploratory approach to enable the expression of whole model transformations in OCL. This approach leverages some OCL extensions proposed for inclusion in the upcoming OCL 2.5: pattern matching and shadow objects. It also relies on a specific execution layer to enable traceability and side effects on models. With model transformations as OCL functions, it becomes possible to use a single, standard, well-known, functional, and formalized model querying language to perform tasks traditionally assigned to model transformation languages. Thus, functional techniques such as function composition and higher-order become directly applicable to model transformations.