In the academic literature, many uses of the Object Constraint Language (OCL) have been proposed. By contrast, the utilization of OCL in contemporary modelling tools lags behind, suggesting that leverage of OCL remains limited in practice. We consider this undeserved, and present a scheme for partially evaluating OCL expressions that allows one to capitalize on given OCL specifications for a wide array of purposes using a single implementation: a partial evaluator of OCL.

Attribute grammars decorate the nodes of a program's parse tree with attributes whose values are defined by equations encoding the (static) semantics of a programming language. We show how replacing the equations of an attribute grammar with equivalent constraints that can be solved by a constraint solver allows us to compute repairs of a malformed program solely from a specification that was originally designed for checking its well-formedness. We present two repair modes --- shallow and deep fixing --- whose computed repair alternatives are guaranteed to repair every error on which they are invoked. While shallow fixing may introduce new errors, deep fixing never does; to make it tractable, we implement it using neighborhood search. We demonstrate the feasibility of our approach by implementing it on top of ExtendJ, an attribute grammar based Java compiler, and by applying it to an example from the Java EE context, detecting and fixing well-formedness errors (both real and injected) in a body of 14 open-source subject programs.

Model-driven engineering suggests that models are the primary artefacts of software development. This means that models may be refactored even after code has been generated from them, in which case the code must be changed to reflect the refactoring. However, as we show neither re-generating the code from the refactored model nor applying an equivalent refactoring to the generated code is sufficient to keep model and code in sync - rather, model and code need to be refactored jointly. To enable this, we investigate the technical requirements of model/code co-refactoring, and implement a model-driven solution that we evaluate using a set of open-source programs and their structural models. Results suggest that our approach is feasible.