Tracing program transformations with string origins

Program transformations play an important role in domain-specific languages and model-driven development. Tracing the execution of such transformations has well-known benefits for debugging, visualization and error reporting. In this paper we introduce string origins as a lightweight, generic and portable technique to establish a tracing relation between the textual fragments in the input and output of a program transformation. We discuss the semantics and the implementation of string origins using the Rascal meta programming language as an example. Furthermore, we illustrate the utility of string origins by presenting data structures and operations for tracing generated code, implementing protected regions, performing name resolution, and fixing inadvertent name capture in generated code

A change propagating model transformation language

Model transformations are a key component in Model Driven Development, but most approaches only allow `one shot' transformations to be expressed. Change propagating model transformations are those which can make suitable updates to models after an initial transformation. In this paper I outline the challenges presented by change prop- agating model transformations, before presenting a new change propagating model transformation approach

A Change propagating model transformation language.

Model transformations are a key component in Model Driven Development, but most approaches only allow ‘one shot' transformations to be expressed. Change propagating model transformations are those which can make suitable updates to models after an initial transformation

Extended geometry and gauged maximal supergravity

We consider generalized diffeomorphisms on an extended mega-space associated to the U-duality group of gauged maximal supergravity in four dimensions, E_7. Through the bein for the extended metric we derive dynamical (field-dependent) fluxes taking values in the representations allowed by supersymmetry, and obtain their quadratic constraints from gauge consistency conditions. A covariant generalized Ricci tensor is introduced, defined in terms of a connection for the generalized diffeomorphisms. We show that for any torsionless and metric-compatible generalized connection, the Ricci scalar reproduces the scalar potential of gauged maximal supergravity. We comment on how these results extend to other groups and dimensions.Comment: 41 pages. v2,v3: minor changes and references adde