Holger Krahn

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.

A security architecture for mobile wireless sensor networks

Wireless sensor networks increasingly become viable solutions to many challenging problems and will successively be deployed in many areas in the future. However, deploying new technology without security in mind has often proved to be unreasonably dangerous. We propose a security architecture for self-organizing mobile wireless sensor networks that prevents many attacks these networks are exposed to. Furthermore, it limits the security impact of some attacks that cannot be prevented. We analyse our security architecure and show that it provides the desired security aspects while still being a lightweight solution and thus being applicable for self-organizing mobile wireless sensor networks.

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.

Techniques for lightweight generator refactoring

This paper presents an exercise to facilitate refactoring techniques not only on generated code, but also on generator templates by reusing existing refactoring techniques from the target language. Refactoring is particularly useful if not only the generated classes but also the template defining the result of the code generator can be adapted in a uniform treatment. We describe a simple demonstration prototype that illustrates our approach. The demonstration is based on the idea to define the templates for code generation themselves as compilable and therefore refactorable source code. However, this limits the directives embedded in the template used for code generation, as we have to embed those as comments. We explore how far this approach carries and where its limits are.