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Open source software (OSS) development communities are typically very specialised, on the one hand, and experience high turnover, on the other. Combination of specialization and turnover can cause parts of the system implemented in a certain programming language to become unmaintainable, if knowledge of that language has disappeared together with the retiring developers. Inspired by measures of linguistic diversity from the study of natural languages, we propose a method to quantify the risk of not having maintainers for code implemented in a certain programming language. To illustrate our approach, we studied risks associated with different languages in Emacs, and found examples of low risk due to high popularity (e.g., C, Emacs Lisp); low risk due to similarity with popular languages (e.g., C++, Java, Python); or high risk due to both low popularity and low similarity with popular languages (e.g., Lex). Our results show that methods from the social sciences can be successfully applied in the study of information systems, and open numerous avenues for future research.

Small languages are gaining popularity in the software engineering community. The development of MOF and EMF has given the Domain Specific Language community a tremendous boost. In this tutorial the basic aspects of model driven engineering in combination with Domain Specific Languages will be discussed. The focus is on textual Domain Specific Languages developed using the language invention pattern. The notion of abstract syntax will be linked to metamodels as well as the definition of concrete syntax. Defining static and dynamic semantics will be discussed. A small but non trivial Domain Specific Language SLCO will be used to illustrate our ideas.

A formal definition of the semantics of a domain-specific language (DSL) is a key prerequisite for the verification of the correctness of models specified using such a DSL and of transformations applied to these models. For this reason, we implemented a prototype of the semantics of a DSL for the specification of systems consisting of concurrent, communicating objects. Using this prototype, models specified in the DSL can be transformed to labeled transition systems (LTS). This approach of transforming models to LTSs allows us to apply existing tools for visualization and verification to models with little or no further effort. The prototype is implemented using the ASF+SDF Meta-Environment, an IDE for the algebraic specification language ASF+SDF, which offers efficient execution of the transformation as well as the ability to read models and produce LTSs without any additional pre or post processing., In Proceedings AMMSE 2011, arXiv:1106.5962

Graphical diagrams are the main modelling constructs offered by the popular modelling language UML. Because textual representations of models also have their benefits, we investigated the integration of textual and graphical modelling languages, by comparing two approaches. One approach uses grammarware and the other uses modelware. As a case study, we implemented two versions of a textual alternative for Activity Diagrams, which is an example of a surface language. This paper describes our surface language, the two approaches, and the two implementations that follow these approaches. Keywords: Grammarware; modelware; surface language.

We present an overview of rewriting-based systems that were presented at the workshop.

In this paper we propose a technique to automate the process of building translators between operations languages, a family of DSLs used to program satellite operations procedures. We exploit the similarities between those languages to semi-automatically build a transformation schema between them, through the use of annotated grammars. To improve the overall translation process even more, reducing its complexity, we also propose an intermediate representation common to all operations languages. We validate our approach by semi-automatically deriving translators between some operations languages, using a prototype tool which we implemented for that purpose.

Generic language technology research focuses on the development of fundamental techniques for language processing. The Asf+Sdf Meta-Environment, an interactive development environment for the automatic generation of interactive systems, is an example of research in this field. The Meta-Environment has been applied in various projects in order to enable the development of high quality tools for the analysis and transformation of large software systems written in languages such as C, Java, Cobol, and PL/I. The Meta-Environment offers the interactive construction of language definitions and the generation of tools given these definitions. Over the years, this system has been used in a variety of academic and industrial projects ranging from formal program manipulation to conversion of industrial Cobol systems.

An environment for the Common Algebraic Specification Language CASL consists of several independent tools. A number of CASL tools have been built using the algebraic specification formalism ASF+SDF and the ASF+SDF Meta-Environment. CASL supports user-defined syntax which is non-trivial to process: ASF+SDF offers a powerful parsing technology (Generalized LR). Its interactive development environment facilitates rapid prototyping complemented by early detection and correction of errors. A number of core technologies developed for the ASF+SDF Meta-Environment can be reused in the context of CASL . Furthermore, an instantiation of a generic format developed for the representation of ASF+SDF specifications and terms provides a CASL -specific exchange format.

International audience; In this paper we present an approach to specifying opera- tor precedence based on declarative disambiguation constructs and an implementation mechanism based on grammar rewriting. We identify a problem with existing generalized context-free parsing and disambigua- tion technology: generating a correct parser for a language such as OCaml using declarative precedence specification is not possible without resorting to some manual grammar transformation. Our approach provides a fully declarative solution to operator precedence specification for context-free grammars, is independent of any parsing technology, and is safe in that it guarantees that the language of the resulting grammar will be the same as the language of the specification grammar. We evaluate our new approach by specifying the precedence rules from the OCaml reference manual against the highly ambiguous reference grammar and validate the output of our generated parser.

Model comparison includes three major concerns: presentation, calculation, and visualization of model differences. In this paper we address the concern of visualization of model differences in the context of model configuration management systems. Since models are considered the main artifacts in model configuration management systems, we require that the differences between models are represented by means of a differences model, which conforms to a differences metamodel. The traditional approaches to visualization of model differences based on a textual, tree-like, or even diagrammatic representation of differences do not scale well in the presence of large differences models. The cause for this is that it gets harder to comprehend the meaning of differences as the size of the differences models increase. We focus on this problem and propose a solution that extends and combines two existing approaches, namely polymetric views and a generic visualization framework for metamodel-based languages. Polymetric views offer good overview, zoom, and filtering capabilities. A visualization framework for metamodel-based languages is used to visualize differences details. By using the combination of these two approaches, it becomes easier to comprehend the meaning of differences even in large models. This paper describes both the details of our solution, and a generic tool that implements the described solution.

The original publication is available at www.springerlink.com; International audience; This paper presents the main results and conclusions of the Third Rewrite Engines Competition (REC III). This edition of the competition took place as part of the 8th Workshop on Rewriting Logic and its Applications (WRLA 2010), and the systems ASF+SDF, Maude, Stratego/XT, Tom, and TXL participated in it.

Evolution of programming languages requires co-evolution of static analysis tools designed for these languages. Traditional approaches to static analysis, e.g., those based on Structural Operational Semantics (SOS), assume, however, that the syntax and the semantics of the programming language under consideration are fixed. Language modification is, therefore, likely to cause redevelopment of the analysis techniques and tools. Moreover, the redevelopment cost can discourage the language engineers from improving the language design. To address the co-evolution problem we suggest to base static analyses on modular structural operational semantics (MSOS). By using an intrinsically modular formalism, type rules can be added, removed or modified easily. We illustrate our approach by developing an MSOSbased type analysis technique for Chi, a domain specific language for hybrid systems engineering.

One of the key points of model-driven engineering is raising the level of abstraction in software development. This phenomenon is not new. In the sixties of the previous century, the first high-level programming languages were developed and they also increased the abstraction level of software development. The development of high-level programming languages initiated research on compilers and programming environments. This research eventually matured into generic language technology: the description of (programming) languages and tooling to generate compilers and programming environments. The model-driven engineering community is developing tools to analyze models and to transform models into code. The application of generic language technology, or at least the lessons learnt by this community, can be beneficial for the model-driven engineering community. By means of a number of case studies it will be shown how generic language technology research can be useful for the development of model-driven engineering technology.

There exist many formalisms for modeling the behavior of (software) systems. These formalisms serve different purposes. Process algebras are used for algebraic and axiomatic reasoning about the behavior of distributed systems. UML state machines are suitable for automatic software generation. We have developed a transformation from the process algebra ACP into UML state machines to enable automatic software generation from process algebra models. This transformation needs to preserve both behavioral and structural properties. The combination of these preservation requirements gives rise to a semantic gap. It implies that we cannot transform ACP models into UML state machines on a syntactic level only. We address this semantic gap and propose a way of bridging it. To validate our proposal, we have implemented a tool for automatic transformation of ACP process algebra models into UML state machines.

In this paper we present the fusion of generalized LR parsing and scannerless parsing. This combination supports syntax definitions in which all aspects (lexical and context-free) of the syntax of a language are defined explicitly in one formalism. Furthermore, there are no restrictions on the class of grammars, thus allowing a natural syntax tree structure. Ambiguities that arise through the use of unrestricted grammars are handled by explicit disambiguation constructs, instead of implicit defaults that are taken by traditional scanner and parser generators. Hence, a syntax definition becomes a full declarative description of a language. Scannerless generalized LR parsing is a viable technique that has been applied in various industrial and academic projects.

The Asf+Sdf Meta-Environment is an interactive development environment for the automatic generation of interactive systems for constructing language definitions and generating tools for them. Over the years, this system has been used in a variety of academic and commercial projects ranging from formal program manipulation to conversion of COBOL systems. Since the existing implementation of the Meta-Environment started exhibiting more and more characteristics of a legacy system, we decided to build a completely new, component-based, version. We demonstrate this new system and stress its open architecture.

This paper describes the development of a new \elan\ parser using \asdf\ parsing technology. \asdf\ and \elan\ are two modern rule-based systems. Both systems have their own features and application domains, however, both formalism have user-defined syntax for defining rewrite rules. The \asdf\ Meta-Environment uses powerful and efficient generic parsing tools, whereas the \elan\ parser is based on an Earley parser. Furthermore, the \elan\ syntax is ``hard-wired'''' in the parser, which makes adaptations of the syntax cumbersome. The use of \asdf\ parsing technology makes the \elan\ syntax more open and adaptable, however, some features of the \elan\ syntax makes the development of a parser a challenging problem.