Steven Völkel

MontiCore: a framework for compositional development of domain specific languages

Domain specific languages (DSLs) are increasingly used today. Coping with complex language definitions, evolving them in a structured way, and ensuring their error freeness are the main challenges of DSL design and implementation. The use of modular language definitions and composition operators are therefore inevitable in the independent development of language components. In this article, we discuss these arising issues by describing a framework for the compositional development of textual DSLs and their supporting tools. We use a redundance-free definition of a readable concrete syntax and a comprehensible abstract syntax as both representations significantly overlap in their structure. For enhancing the usability of the abstract syntax, we added concepts like associations and inheritance to a grammar-based definition in order to build up arbitrary graphs (as known from metamodeling). Two modularity concepts, grammar inheritance and embedding, are discussed. They permit compositional language definition and thus simplify the extension of languages based on already existing ones. We demonstrate that compositional engineering of new languages is a useful concept when project-individual DSLs with appropriate tool support are defined.

MontiCore: Modular Development of Textual Domain Specific Languages

Reuse is a key technique for a more efficient development and ensures the quality of the results. In object technology explicit encapsulation, interfaces, and inheritance are well-known principles for independent development that enable combination and reuse of developed artifacts. In this paper we apply modularity concepts for domain specific languages (DSLs) and discuss how they help to design new languages by extending existing ones and composing fragments to new DSLs. We use an extended grammar format with appropriate tool support that avoids redefinition of existing functionalities by introducing language inheritance and embedding as first class artifacts in a DSL definition. Language embedding and inheritance is not only assisted by the parser, but also by the editor, and algorithms based on tree traversal like context checkers, pretty printers, and code generators. We demonstrate that compositional engineering of new languages becomes a useful concept when starting to define project-individual DSLs using appropriate tool support.

Integrated definition of abstract and concrete syntax for textual languages

An understandable concrete syntax and a comprehensible abstract syntax are two central aspects of defining a modeling language. Both representations of a language significantly overlap in their structure and also information, but may also differ in parts of the information. To avoid discrepancies and problems while handling the language, concrete and abstract syntax need to be consistently defined. This will become an even bigger problem, when domain specific languages will become used to a larger extent. In this paper we present an extended grammar format that avoids redundancy between concrete and abstract syntax by allowing an integrated definition of both for textual modeling languages. For an amendment of the usability of the abstract syntax it furthermore integrates meta-modeling concepts like associations and inheritance into a well-understood grammar-based approach. This forms a sound foundation for an extensible grammar and therefore language definition.

An algebraic view on the semantics of model composition

Due to the increased complexity of software development projects more and more systems are described by models. The sheer size makes it impractical to describe these systems by a single model. Instead many models are developed that provide several complementary views on the system to be developed. This however leads to a need for compositional models. This paper describes a foundational theory of model composition in form of an algebra to explicitly clarify different variants and uses of composition, their interplay with the semantics of the involved models and their composition operators.

MontiCore: a framework for the development of textual domain specific languages

In this paper we demonstrate a framework for the efficient development of textual domain specific languages and supporting tools. We use a redundance-free and compact definition of a readable concrete syntax and a comprehensible abstract syntax as both representations significantly overlap in their structure. To further improve the usability of the abstract syntax, this definition format integrates additional concepts like associations and inheritance into the well-understood grammar-based approach. Modularity concepts like language inheritance and embedding are used to simplify the development of languages based on already existing ones. In addition, the generation of editors and a template approach for code generation is explained.

Integration of heterogeneous modeling languages via extensible and composable language components

Effective model-driven engineering of complex systems requires to appropriately describe different specific system aspects. To this end, efficient integration of different heterogeneous modeling languages is essential. Modeling language integaration is onerous and requires in-depth conceptual and technical knowledge and effort. Traditional modeling lanugage integration approches require language engineers to compose monolithic language aggregates for a specific task or project. Adapting these aggregates to different contexts requires vast effort and makes these hardly reusable. This contribution presents a method for the engineering of grammar-based language components that can be independently developed, are syntactically composable, and ultimately reusable. To this end, it introduces the concepts of language aggregation, language embedding, and language inheritance, as well as their realization in the language workbench MontiCore. The result is a generalizable, systematic, and efficient syntax-oriented composition of languages that allows the agile employment of modeling languages efficiently tailored for individual software projects.

Composition of Heterogeneous Modeling Languages

Model-driven engineering aims at managing the complexity of large software systems by describing their various aspects through dedicated models. This approach requires to employ different modeling languages that are tailored to specific system aspects, yet can be interpreted together to form a coherent description of the total system. Traditionally, implementations of such integrated languages have been monolithic language projects with little modularization and reuse of language parts.

Generative software development

Generation of software from modeling languages such as UML and domain specific languages (DSLs) has become an important paradigm in software engineering. In this contribution, we present some positions on software development in a model based, generative manner based on home grown DSLs as well as the UML. This includes development of DSLs as well as development of models in these languages in order to generate executable code, test cases or models in different languages. Development of formal DSLs contains concepts of metamodels or grammars (syntax), context conditions (static analysis and quality assurance) as well as possibilities to define the semantics of a language. The growing number and complexity of DSLs is addressed by concepts for the modular and compositional development of languages and their tools. Moreover, we introduce approaches to code generation and model transformation. Finally, we give an overview of the relevance of DSLs for various steps of software development processes.

Agile development with domain specific languages

An increasing number of software development projects uses domain specific languages (DSLs) at least at one stage. Such languages allow domain experts to take part in the product development, and they can often contribute to improved efficiency. As a drawback, the development of a DSL is a complex and error-prone software development process itself, which causes additional efforts and costs. Moreover, the actual software product and the DSL are often developed concurrently, and the requirements for the DSL may change according to the needs of developers of the actual product. Therefore, we have to address two interdependent development processes: the product development process, in which we may need to react on requirement changes by the customer quickly, and the language development process, in which we want to define an adaptable and extensible DSL.

Modeling in Software Engineering (MiSE 09)

The Modeling in Software Engineering (MiSE) workshop series provides a forum for discussing the challenges associated with modeling software and with incorporating modeling practices into the software development process. The main goal is to further promote cross-fertilization between the modeling communities (e.g., MODELS) and software-engineering communities.