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Graphical diagrams are the main modelling constructs offered by the popular modelling language UML. Because textual representations of models also have their benefits, we investigated the integration of textual and graphical modelling languages, by comparing two approaches. One approach uses grammarware and the other uses modelware. As a case study, we implemented two versions of a textual alternative for Activity Diagrams, which is an example of a surface language. This paper describes our surface language, the two approaches, and the two implementations that follow these approaches. Keywords: Grammarware; modelware; surface language.

We present an overview of rewriting-based systems that were presented at the workshop.

In this paper we propose a technique to automate the process of building translators between operations languages, a family of DSLs used to program satellite operations procedures. We exploit the similarities between those languages to semi-automatically build a transformation schema between them, through the use of annotated grammars. To improve the overall translation process even more, reducing its complexity, we also propose an intermediate representation common to all operations languages. We validate our approach by semi-automatically deriving translators between some operations languages, using a prototype tool which we implemented for that purpose.

An environment for the Common Algebraic Specification Language CASL consists of several independent tools. A number of CASL tools have been built using the algebraic specification formalism ASF+SDF and the ASF+SDF Meta-Environment. CASL supports user-defined syntax which is non-trivial to process: ASF+SDF offers a powerful parsing technology (Generalized LR). Its interactive development environment facilitates rapid prototyping complemented by early detection and correction of errors. A number of core technologies developed for the ASF+SDF Meta-Environment can be reused in the context of CASL . Furthermore, an instantiation of a generic format developed for the representation of ASF+SDF specifications and terms provides a CASL -specific exchange format.

Model transformations are commonly used to transform models suited for one purpose (e.g., describing a solution in a particular domain) to models suited for a related but different purpose (e.g., simulation or execution). The disadvantage of a transformational approach, however, is that feedback acquired from analyzing transformed models is not reported on the level of the problem domain but on the level of the transformed model. Expressing the feedback on the level of the problem domain requires improving traceability in model transformations. We propose to visualize traceability links in (chains of) model transformations, thus making traceability amenable for analysis.

Correctness of model transformations is a prerequisite for generating correct implementations from models. Given refining model transformations that preserve desirable properties, models can be transformed into correct-by-construction implementations. However, proving that model transformations preserve properties is far from trivial. Therefore, we aim for simple correctness proofs by designing model transformations that are as fine-grained as possible. Furthermore, we advocate the reuse of model transformations to reduce the number of proofs. For a simple domain-specific language, SLCO, we define a formal framework to reason about the correctness, reusability, and composition of the fine-grained model transformations used to transform a given model to three target languages: NQC, Promela and POOSL. The correctness criterion induces that the original model and the resulting model obtained after a proper sequence of transformations have the same observable behavior.

In this paper we discuss, and provide a generic solution to the problem referred to as model co-evolution: How to evolve models in case their metamodels evolve? We solve this problem by extending a traditional three-step approach. In the first step, differences between an original and an evolved metamodel are determined. Unlike traditional approaches, we treat metamodels as models conforming to a special metamodel, thus the same difference representation and calculation mechanisms for metamodels as for models are used in our approach. In the second step, metamodel differences are classified into four groups based on their possible influence on co-evolving models, and the possibilities of handling them automatically. We adopt two of these groups (non-breaking and breaking and resolvable differences) from the existing co-evolution approaches, and we introduce two new groups (breaking and semi-resolvable and breaking and human-resolvable differences). In the third step, based on the determined metamodel differences, a generic co-evolution transformation is invoked. This transformation takes the metamodel differences, and a model as arguments, and returns an adapted model. We validated our approach by incorporating our method into a prototype tool for generic model co-evolution, and by testing this tool on a large set of metamodels and models.

The original publication is available at www.springerlink.com; International audience; This paper presents the main results and conclusions of the Third Rewrite Engines Competition (REC III). This edition of the competition took place as part of the 8th Workshop on Rewriting Logic and its Applications (WRLA 2010), and the systems ASF+SDF, Maude, Stratego/XT, Tom, and TXL participated in it.

In this paper we consider two major concerns in the process of comparing two models -- representation and calculation of model differences. Based on previous work, we adopt a set of requirements which a difference representation should satisfy in order to be seamlessly used in Model Driven Engineering environments. Given these requirements, we represent model differences by means of a differences model, which conforms to a differences metamodel. We show that the traditional meta-modeling approaches, which conform to the four-layered meta-modeling architecture, lack means for the specification of differences metamodels which fully satisfy the specified requirements. Consequently, we specify a metametamodel which offers a different view on the traditional metamodeling approaches and we use it to define the differences metamodel which fully satisfies the specified requirements. Traditional approaches to difference calculation consider models as trees, and use the structure provided by these trees to guide the calculation process. The calculation algorithms used in those approaches are based on matching elements in one model to elements in another model by using one of the following four types of matching: static-identity, signature-based, similarity-based, and language-specific. We adopt the same philosophy, but unlike the traditional approaches which have a fixed calculation algorithm and a fixed matching type, we provide a calculation algorithm that is highly configurable and is designed such that all four traditional types of matching can be used together. As a proof-of-concept we have implemented a tool which allows representation, calculation, and visualization of model differences.

International audience; The 2nd Rewrite Engines Competition (REC) was celebrated as part of the 7th Workshop on Rewriting Logic and its Applications (WRLA 2008). In this edition of the competition participated five systems, namely ASF+SDF, Maude, Stratego/XT, Termware, and Tom. We explain here how the competition was organized and conducted, and present its main results and conclusions.

There exist many formalisms for modeling the behavior of (software) systems. These formalisms serve different purposes. Process algebras are used for algebraic and axiomatic reasoning about the behavior of distributed systems. UML state machines are suitable for automatic software generation. We have developed a transformation from the process algebra ACP into UML state machines to enable automatic software generation from process algebra models. This transformation needs to preserve both behavioral and structural properties. The combination of these preservation requirements gives rise to a semantic gap. It implies that we cannot transform ACP models into UML state machines on a syntactic level only. We address this semantic gap and propose a way of bridging it. To validate our proposal, we have implemented a tool for automatic transformation of ACP process algebra models into UML state machines.

This paper describes the development of a new \elan\ parser using \asdf\ parsing technology. \asdf\ and \elan\ are two modern rule-based systems. Both systems have their own features and application domains, however, both formalism have user-defined syntax for defining rewrite rules. The \asdf\ Meta-Environment uses powerful and efficient generic parsing tools, whereas the \elan\ parser is based on an Earley parser. Furthermore, the \elan\ syntax is ``hard-wired'''' in the parser, which makes adaptations of the syntax cumbersome. The use of \asdf\ parsing technology makes the \elan\ syntax more open and adaptable, however, some features of the \elan\ syntax makes the development of a parser a challenging problem.