Arie van Deursen

Domain-specific languages: an annotated bibliography

We survey the literature available on the topic of domain-specific languages as used for the construction and maintenance of software systems. We list a selection of 75 key publications in the area, and provide a summary for each of the papers. Moreover, we discuss terminology, risks and benefits, example domain-specific languages, design methodologies, and implementation techniques.

The ASF+SDF Meta-environment: A Component-Based Language Development Environment

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.

Little languages: little maintenance

So-called little, or domain-specific languages (DSLs), have the potential to make software maintenance simpler: domain-experts can directly use the DSL to make required routine modifications. At the negative side, however, more substantial changes may become more difficult: such changes may involve altering the domain-specific language. This will require compiler technology knowledge, which not every commercial enterprise has easily available. Based on experience taken from industrial practice, we discuss the role of DSLs in software maintenance, the dangers introduced by using them, and techniques for controlling the risks involved.

Identifying objects using cluster and concept analysis

Many approaches to support (semi-automatic) identification of objects in legacy code take data structures as the starting point for candidate classes. Unfortunately, legacy data structures tend to grow over time, and may contain many unrelated fields at the time of migration. We propose a method for identifying objects by semi-automatically restructuring the legacy data structures. Issues involved include the selection of record fields of interest, the identification of procedures actually dealing with such fields, and the construction of coherent groups of fields and procedures into candidate classes. We explore the use of cluster and concept analysis for the purpose of object identification, and we illustrate their effect on a 100000 LOC Cobol system. Furthermore, we use these results to contrast clustering with concept analysis techniques.

Invariant-based automatic testing of AJAX user interfaces

AJAX-based Web 2.0 applications rely on stateful asynchronous client/server communication, and client-side runtime manipulation of the DOM tree. This not only makes them fundamentally different from traditional web applications, but also more error-prone and harder to test. We propose a method for testing AJAX applications automatically, based on a crawler to infer a flow graph for all (client-side) user interface states. We identify AJAX-specific faults that can occur in such states (related to DOM validity, error messages, discoverability, back-button compatibility, etc.) as well as DOM-tree invariants that can serve as oracle to detect such faults. We implemented our approach in ATUSA, a tool offering generic invariant checking components, a plugin-mechanism to add application-specific state validators, and generation of a test suite covering the paths obtained during crawling. We describe two case studies evaluating the fault revealing capabilities, scalability, required manual effort and level of automation of our approach.

Crawling Ajax-Based Web Applications through Dynamic Analysis of User Interface State Changes

Using JavaScript and dynamic DOM manipulation on the client side of Web applications is becoming a widespread approach for achieving rich interactivity and responsiveness in modern Web applications. At the same time, such techniques---collectively known as Ajax---shatter the concept of webpages with unique URLs, on which traditional Web crawlers are based. This article describes a novel technique for crawling Ajax-based applications through automatic dynamic analysis of user-interface-state changes in Web browsers. Our algorithm scans the DOM tree, spots candidate elements that are capable of changing the state, fires events on those candidate elements, and incrementally infers a state machine that models the various navigational paths and states within an Ajax application. This inferred model can be used in program comprehension and in analysis and testing of dynamic Web states, for instance, or for generating a static version of the application. In this article, we discuss our sequential and concurrent Ajax crawling algorithms. We present our open source tool called Crawljax, which implements the concepts and algorithms discussed in this article. Additionally, we report a number of empirical studies in which we apply our approach to a number of open-source and industrial Web applications and elaborate on the obtained results.

An exploratory study of the pull-based software development model

The advent of distributed version control systems has led to the development of a new paradigm for distributed software development; instead of pushing changes to a central repository, developers pull them from other repositories and merge them locally. Various code hosting sites, notably Github, have tapped on the opportunity to facilitate pull-based development by offering workflow support tools, such as code reviewing systems and integrated issue trackers. In this work, we explore how pull-based software development works, first on the GHTorrent corpus and then on a carefully selected sample of 291 projects. We find that the pull request model offers fast turnaround, increased opportunities for community engagement and decreased time to incorporate contributions. We show that a relatively small number of factors affect both the decision to merge a pull request and the time to process it. We also examine the reasons for pull request rejection and find that technical ones are only a small minority.

Language Prototyping: An Algebraic Specification Approach: Vol. V

From the Publisher: Language prototyping provides a means to generate language implementations automatically from high-level language definitions. This volume presents an algebraic specification approach to language prototyping; and is centered around the ASF+SDF formalism and Meta-Environment. The volume is an integrated collection of articles covering a number of case studies, and includes several chapters proposing new techniques for deriving advanced language implementations. The accompanying software is freely available.

The impact of social media on software engineering practices and tools

Todays generation of software developers frequently make use of social media, either as an adjunct or integrated into a wide range of tools ranging from code editors and issue trackers, to IDEs and web-based portals. The role of social media usage in software engineering is not well understood, and yet the use of these mechanisms influences software development practices. In this position paper, we advocate for research that strives to understand the benefits, risks and limitations of using social media in software development at the team, project and community levels. Guided by the implications of current tools and social media features, we propose a set of pertinent research questions around community involvement, project coordination and management, as well as individual software development activities. Answers to these questions will guide future software engineering tool innovations and software development team practices.

Work practices and challenges in pull-based development: the contributor's perspective

The pull-based development model is an emerging way of contributing to distributed software projects that is gaining enormous popularity within the open source software (OSS) world. Previous work has examined this model by focusing on projects and their owners---we complement it by examining the work practices of project contributors and the challenges they face. We conducted a survey with 645 top contributors to active OSS projects using the pull-based model on GitHub, the prevalent social coding site. We also analyzed traces extracted from corresponding GitHub repositories. Our research shows that: contributors have a strong interest in maintaining awareness of project status to get inspiration and avoid duplicating work, but they do not actively propagate information; communication within pull requests is reportedly limited to low-level concerns and contributors often use communication channels external to pull requests; challenges are mostly social in nature, with most reporting poor responsiveness from integrators; and the increased transparency of this setting is a confirmed motivation to contribute. Based on these findings, we present recommendations for practitioners to streamline the contribution process and discuss potential future research directions.