Layout Specification on the Concrete and Abstract Syntax Level of a Diagram Language

A visual language consists of several visual component types, e.g. states or transitions in DFAs. Nowadays, the language itself is usually specified via a meta model. To make a diagram look nice, a layouter is required. This layouter may either operate on the concrete syntax level, i.e., on the visual components, or on the abstract syntax level, i.e., on the model instance. In this paper we present an approach that is capable of specifying a flexible layout on both, the concrete as well as the abstract syntax level of a diagram. The approach uses pattern-based transformations. Besides structured editing, it also supports free-hand editing, a challenging task for the layouter. We introduce how such a specification can be created and examine the advantages and shortcomings of each of either operating on the concrete syntax level or on the abstract syntax level

Event-driven grammars: Relating abstract and concrete levels of visual languages

The final publication is available at Springer via http://dx.doi.org/10.1007/s10270-007-0051-2In this work we introduce event-driven grammars, a kind of graph grammars that are especially suited for visual modelling environments generated by meta-modelling. Rules in these grammars may be triggered by user actions (such as creating, editing or connecting elements) and in their turn may trigger other user-interface events. Their combination with triple graph transformation systems allows constructing and checking the consistency of the abstract syntax graph while the user is building the concrete syntax model, as well as managing the layout of the concrete syntax representation. As an example of these concepts, we show the definition of a modelling environment for UML sequence diagrams. A discussion is also presented of methodological aspects for the generation of environments for visual languages with multiple views, its connection with triple graph grammars, the formalization of the latter in the double pushout approach and its extension with an inheritance concept.This work has been partially sponsored by the Spanish Ministry of Education and Science with projects MOSAIC (TSI2005-08225-C07-06) and MODUWEB (TIN 2006-09678)

On the role of domain ontologies in the design of domain-specific visual modeling langages

Domain-Specific Visual Modeling Languages should provide notations and abstractions that suitably support problem solving in well-defined application domains. From their user’s perspective, the language’s modeling primitives must be intuitive and expressive enough in capturing all intended aspects of domain conceptualizations. Over the years formal and explicit representations of domain conceptualizations have been developed as domain ontologies. In this paper, we show how the design of these languages can benefit from conceptual tools developed by the ontology engineering community

Ludo: A Case Study for Graph Transformation Tools

In this paper we describe the Ludo case, one of the case studies of the AGTIVE 2007 Tool Contest (see [22]). After summarising the case description, we give an overview of the submitted solutions. In particular, we propose a number of dimensions along which choices had to be made when solving the case, essentially setting up a solution space; we then plot the spectrum of solutions actually encountered into this solution space. In addition, there is a brief description of the special features of each of the submissions, to do justice to those aspects that are not distinguished in the general solution space

Object Oriented and Rule-based Design of Visual Languages using Tiger

In this paper we present the state-of-the-art of the TIGER environment for the generation of visual editor plug-ins in Eclipse, with the focus on its Designer component, a visual environment for object oriented and rule-based design of visual languages. Based on an alphabet for finite automata we show how a visual language can be designed by defining the abstract and concrete syntax of the visual language and syntax directed editing operations in the generated editor plug-in. For the graphical layout we use the Graphical Editing Framework (GEF) of ECLIPSE which offers an efficient and standardized way for graphical layouting

Pattern-Based Layout Specifications for Visual Language Editors

When creating an editor for a visual language, a challenging task is the layout specification. Many visual languages, e.g., Ecore diagrams or Petri nets, show similar layout characteristics, and hence reuse of layout behavior should be enabled. For that purpose, we introduce the concept of layout patterns, which encapsulates certain layout behavior. With the approach, it is possible to combine different layout algorithms, e.g., standard graph drawing algorithms and constraint-based algorithms. In addition, rule-based layout algorithms may be used that are specifically tailored to the interactive nature of visual language editors

Engineering Object-Oriented Semantics Using Graph Transformations

In this paper we describe the application of the theory of graph transformations to the practise of language design. We have defined the semantics of a small but realistic object-oriented language (called TAAL) by mapping the language constructs to graphs and their operational semantics to graph transformation rules. In the process we establish a mapping between UML models and graphs. TAAL was developed for the purpose of this paper, as an extensive case study in engineering object-oriented language semantics using graph transformation. It incorporates the basic aspects of many commonly used object-oriented programming languages: apart from essential imperative programming constructs, it includes inheritance, object creation and method overriding. The language specification is based on a number of meta-models written in UML. Both the static and dynamic semantics are defined using graph rewriting rules. In the course of the case study, we have built an Eclipse plug-in that automatically transforms arbitrary TAAL programs into graphs, in a graph format readable by another tool. This second tool is called Groove, and it is able to execute graph transformations. By combining both tools we are able to visually simulate the execution of any TAAL program

Generating Meta-Model-Based Freehand Editors

Most visual languages as of today (e.g., UML) are specified using a model in a meta-model-based approach. Editors for such languages have supported structured editing as the only editing mode so far. Free-hand editing that leaves the user more freedom during editing was not supported by any editor or editor framework since parsing has not yet been considered for meta-model-based specifications. This paper describes the diagram editor generator framework DiaMeta that makes use of meta-model-based language specifications and supports free-hand as well as structured editing. For analyzing freely drawn diagrams, DiaMeta parses a graph representation of the diagram by solving a constraint satisfaction problem