From Separate Formal Specifications to Certified Integrated Visual Modelling Techniques and Environments - Position Statement

In this position statement we discuss the state of the art and role of formal specification and modelling techniques in different periods with special focus on the work of the TFS-group at TU-Berlin. In the past (1970 – 1990) single formal specification techniques have been developed with little impact on practical software development. In the present (1990 – 2010) integrated and visual modelling techniques have gained more and more importance. For the future (2010 – 2020) we try to sketch the idea of a Certified Integrated Visual Modelling Technique and Environment based on an integration of graph theory, graph transformation and Petri net theory, short Dynamic Graph and Net Theory

Evolution of negative application conditions on second-order graph rewriting

Graph grammars are a suitable formalism to modeling computational systems. This formalism is based on rules and data-driven transformations capable of simulating real systems, rules have application conditions and post conditions that can change the system state. Moreover the use of graphs allows an intuitive visual interface essential for the modeler. It is well known that software systems are always evolving, evolutions may range from minor refactorings or bug fixes to major interface changes or new architectural design. The formalization of these evolution processes in graph grammars is done via higher-order principles, which allows programmed higher-level rules to induce modifications on lower-level rules, the system rules. In this work, we extend the current framework of higher-order transformations for graph grammars in order to allow the evolution of rules with negative application conditions. Besides this extension, we provide the first working implementation of the whole framework of higher-order graph grammars in the Verigraph tool enabling the practical usage of this techniques.Gramática de grafos é um formalismo para modelagem de sistemas computacionais. Este formalismo é baseado em regras e transformações de dados capazes de simular sistemas reais, regras tem pré e pós condições de aplicação que podem mudar o estado do sistema. Além disso, o uso de grafos permite uma interface visual intuitiva, que é essencial para o modelador. Se sabe que sistemas computacionais estão sempre evoluindo, essas evoluções podem varias de pequenas refatorações ou correções de problemas, até mudanças maiores em interfaces ou nova arquitetura. A formalização deste processo de evolução em gramáticas de grafos é feita com base em regras de segunda ordem, que possibilitam induzir modificações nas regras da gramática de primeira ordem. Neste trabalho, nós estendemos o framework atual de gramáticas de grafos de segunda ordem de forma a permitir evolução de regras com condições negativas de aplicação. Além desta extensão, nós provemos a primeira implementação do framework de gramáticas de grafos de segunda ordem na ferramenta Verigraph, possibilitando assim o uso na prática destas técnicas

On-the-Fly Construction, Correctness and Completeness of Model Transformations based on Triple Graph Grammars

Triple graph grammars (TGGs) are a formal and intuitive concept for the specification of model transformations. Their main advantage is an automatic derivation of operational rules for bidirectional model transformations, which simplifies specification and enhances usability as well as consistency. In this paper we continue previous work on the formal definition of model transformations based on triple graph rules with negative application conditions (NACs). The new notion of partial source consistency enables us to construct consistent model transformations on-the-fly instead of analyzing consistency of completed model transformations. We show the crucial properties termination, correctness and completeness (including NAC-consistency) for the model transformations resulting from our construction. Moreover we define parallel independence for model transformation steps which allows us to perform partial-order reduction in order to improve efficiency. The results are applicable to several relevant model transformations and in particular to our example transformation from class diagrams to database models

On-the-Fly Construction, Correctness and Completeness of Model Transformations based on Triple Graph Grammars: Long Version

Triple graph grammars (TGGs) are a formal and intuitive concept for the specification of model transformations. Their main advantage is an automatic derivation of operational rules for bidirectional model transformations, which simplifies specification and enhances usability as well as consistency. In this paper we continue previous work on the formal definition of model transformations based on triple graph rules with negative application conditions (NACs). The new notion of partial source consistency enables us to construct consistent model transformations on-the-fly instead of analyzing consistency of completed model transformations. We show the crucial properties termination, correctness and completeness (including NAC-consistency) for the model transformations resulting from our construction. Moreover we define parallel independence for model transformation steps which allows us to perform partial-order reduction in order to improve efficiency. The results are applicable to several relevant model transformations and in particular to our example transformation from class diagrams to database models