Completeness and Correctness of Model Transformations based on Triple Graph Grammars with Negative Application Conditions (Long Version)

Model transformations are a key concept for modular and distributed model driven development. In this context, triple graph grammars have been investigated and applied to several case studies and they show a convenient combination of formal and intuitive specification abilities. Especially the automatic derivation of forward and backward transformations out of just one specified set of rules for the integrated model simplifies the specification and enhances usability as well as consistency. Since negative application conditions (NACs) are key ingredient for many model transformations based on graph transformation we embed them in the concept of triple graph grammars. As a first main result we can extend the composition/decomposition result for triple graph grammars to the case with NACs. This allows us to show completeness and correctness of model transformations based on rules with NACs and furthermore, we can extend the characterization of information preserving model transformations to the case with NACs. The presented results are applicable to several model transformations and in particular to the well known model transformation from class diagrams to relational data bases, which we present as running example with NACs

Specification and Construction of Control Flow Semantics

In this paper we propose a visual language CFSL for specifying control flow semantics of programming languages. We also present a translation from CFSL to graph production systems (GPS) for flow graph construction; that is, any CFSL specification, say for a language L, gives rise to a GPS that constructs from any L-program (represented as an abstract syntax graph) the corresponding flow graph. The specification language is rich enough to capture complex language constructs, including all of Java

The Joys of Graph Transformation

We believe that the technique of graph transformation offers a very natural way to specify semantics for languages that have dynamic allocation and linking structure; for instance, object-oriented programming languages, but also languages for mobility. In this note we expose, on a rather informal level, the reasons for this belief. Our hope in doing this is to raise interest in this technique and so generate more interest in the fascinating possibilities and open questions of this area.\u

Conditions, constraints and contracts: on the use of annotations for policy modeling.

Organisational policies express constraints on generation and processing of resources. However, application domains rely on transformation processes, which are in principle orthogonal to policy specifications and domain rules and policies may evolve in a non-synchronised way. In previous papers, we have proposed annotations as a flexible way to model aspects of some policy, and showed how they could be used to impose constraints on domain configurations, how to derive application conditions on transformations, and how to annotate complex patterns. We extend the approach by: allowing domain model elements to be annotated with collections of elements, which can be collectively applied to individual resources or collections thereof; proposing an original construction to solve the problem of annotations remaining orphan , when annotated resources are consumed; introducing a notion of contract, by which a policy imposes additional pre-conditions and post-conditions on rules for deriving new resources. We discuss a concrete case study of linguistic resources, annotated with information on the licenses under which they can be used. The annotation framework allows forms of reasoning such as identifying conflicts among licenses, enforcing the presence of licenses, or ruling out some modifications of a licence configuration

Towards a navigational logic for graphical structures

One of the main advantages of the Logic of Nested Conditions, defined by Habel and Pennemann, for reasoning about graphs, is its generality: this logic can be used in the framework of many classes of graphs and graphical structures. It is enough that the category of these structures satisfies certain basic conditions. In a previous paper [14], we extended this logic to be able to deal with graph properties including paths, but this extension was only defined for the category of untyped directed graphs. In addition it seemed difficult to talk about paths abstractly, that is, independently of the given category of graphical structures. In this paper we approach this problem. In particular, given an arbitrary category of graphical structures, we assume that for every object of this category there is an associated edge relation that can be used to define a path relation. Moreover, we consider that edges have some kind of labels and paths can be specified by associating them to a set of label sequences. Then, after the presentation of that general framework, we show how it can be applied to several classes of graphs. Moreover, we present a set of sound inference rules for reasoning in the logic.Peer ReviewedPostprint (author's final draft

Implementing β-Reduction by Hypergraph Rewriting

AbstractThe aim of this paper is to implement the β-reduction in the lambda;-calculus with a hypergraph rewriting mechanism called collapsed lambda;-tree rewriting. It turns out that collapsed lambda;-tree rewriting is sound with respect to β-reduction and complete with respect to the Gross-Knuth strategy. As a consequence, there exists a normal form for a collapsed lambda;-tree if and only if there exists a normal form for the represented λ-term.I am grateful to Renate Klempien-Hinrichs, Detlef Plump, and to the referees for their helpful comments

Generalised compositionality in graph transformation

We present a notion of composition applying both to graphs and to rules, based on graph and rule interfaces along which they are glued. The current paper generalises a previous result in two different ways. Firstly, rules do not have to form pullbacks with their interfaces; this enables graph passing between components, meaning that components may “learn” and “forget” subgraphs through communication with other components. Secondly, composition is no longer binary; instead, it can be repeated for an arbitrary number of components

How to Specify a Graph Transformation Approach A Meta Model for Fujaba1 1Research partially supported by the ESPRIT Working Group APPLIGRAPH and the TMR network GETGRATS.

AbstractApplication-oriented approaches to graph transformation provide structural features beyond vertices and edges, like composition in hierarchical graphs, inheritance in object-oriented graphs, multiplicity constraints, etc.Often, these features have a specific dynamic interpretation which requires complex embedding mechanisms and context conditions. For example, the deletion of a compound node usually implies the deletion of its components.In this paper, we propose the use of a meta graph grammar for the definition of such a complex graph transformation approach. A meta graph grammar is a typed graph grammar whose type graph provides a static description of the structure of graphs, rules, and transformations of the approach. This static meta model, which is comparable to the meta model in the UML specification, is extended by a specification of the rule application operator by means of graphical embedding rules, i.e., the productions of the meta graph grammar. These embedding rules allow a concise visual description of the admissible context embeddings of a rule and of the side effects of the rule application on the context.As a case-study, a meta graph grammar for selected features of the object-oriented graph transformation approach Fujaba is given