Software developers must modify their programs to keep up with changing requirements and designs. Often, a conceptually simple change can require numerous edits that are similar but not identical, leading to errors and omissions. Researchers have designed programming environments to address this problem, but most of these systems are counter-intuitive and difficult to use. By applying a task-centered design process, we developed a visual tool that allows programmers to make complex code transformations in an intuitive manner. This approach uses a representation that aligns well with programmers ’ mental models of programming structures. The visual language combines textual and graphical elements and is expressive enough to support a broad range of code-changing tasks. To simplify learning the system, its user interface scaffolds construction and execution of transformations. An evaluation with Java programmers suggests that the interface is intuitive, easy to learn, and effective on a representative editing task. Author Keywords Transformations, visual languages, cognitive dimensions.

This thesis describes techniques for transforming and analysing functional programs. We operate on a core language, to which Haskell programs can be reduced. We present a range of techniques, all of which have been implemented and evaluated. We make programs shorter by defining a library which abstracts over common data traversal patterns, removing boilerplate code. This library only supports traversals having value-specific behaviour for one type, allowing a simpler programming model. Our library allows concise expression of traversals with competitive performance. We make programs faster by applying a variant of supercompilation. As a result of practical experiments, we have identified modifications to the standard supercompilation techniques – particularly with respect to let bindings and the generalisation technique. We make programs safer by automatically checking for potential patternmatch errors. We define a transformation that takes a higher-order program

Abstract. Domain-specific languages (DSLs) are increasingly used as embedded languages within general-purpose host languages. DSLs provide a compact, dedicated syntax for specifying parts of an application related to specialized domains. Unfortunately, such language extensions typically do not integrate well with the development tools of the host language. Editors, compilers and debuggers are either unaware of the extensions, or must be adapted at a non-trivial cost. We present a novel approach to embed DSLs into an existing host language by leveraging the underlying representation of the host language used by these tools. Helvetia is an extensible system that intercepts the compilation pipeline of the Smalltalk host language to seamlessly integrate language extensions. We validate our approach by case studies that demonstrate three fundamentally different ways to extend or adapt the host language syntax and semantics. 1

Program transformation techniques have reached a maturity level that allows processing high-level language sources in new ways. Not only do they revolutionize the implementation of compilers and interpreters, but with modularity as a design philosophy, they also permit the seamless extension of the syntax and semantics of existing programming languages. The C-Transformers project provides a transformation environment for C, a language that proves to be hard to transform. We demonstrate the effectiveness of C-Transformers by extending C’s instructions and control flow to support Design by Contract. C-Transformers is developed by members of the LRDE: EPITA undergraduate students. 1

AUTOBAYES is a fully automatic, schema-based program synthesis system for statistical data analysis applications. Its core component is a schema library, i.e., a collection of generic code templates with associated applicability constraints which are instantiated in a problem-specific way during synthesis. syntax (i.e., Prolog terms) to formulate the templates. However, the conceptual distance between this abstract representation and the concrete syntax of the generated programs makes the schemas hard to create and maintain. In this paper we describe how AUTOBAYES is retrofitted with concrete syntax. We show how it is integrated into Prolog and describe how the seamless interaction of concrete syntax fragments with AUTOBAYES’s remaining “legacy” meta-programming kernel based on abstract syntax is achieved. We apply the approach to gradually migrate individual schemas without forcing a disruptive migration of the entire system to a different meta-programming language. First experiences show that a smooth migration can be achieved. Moreover, it can result

Abstract. We present MJ: a language for specifying general classes whose members are produced by iterating over members of other classes. We call this technique “class morphing ” or just “morphing”. Morphing extends the notion of genericity so that not only types of methods and fields, but also the structure of a class can vary according to type variables. This offers the ability to express common programming patterns in a highly generic way that is otherwise not supported by conventional techniques. For instance, morphing lets us write generic proxies (i.e., classes that can be parameterized with another class and export the same public methods as that class); default implementations (e.g., a generic do-nothing type, configurable for any interface); semantic extensions (e.g., specialized behavior for methods that declare a certain annotation); and more. MJ’s hallmark feature is that, despite its emphasis on generality, it allows modular type checking: an MJ class can be checked independently of its uses. Thus, the possibility of supplying a type parameter that will lead to invalid code is detected early—an invaluable feature for highly general components that will be statically instantiated by other programmers. 1

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Since annotations were added to the Java language, many frameworks have moved to using annotated Plain Old Java Objects (POJOs) in their newest releases. Legacy applications are thus forced to undergo extensive restructuring in order to migrate from old framework versions to new versions based on annotations (Version Lock-in). Additionally, because annotations are embedded in the application code, changing between framework vendors may also entail largescale manual changes (Vendor Lock-in). This paper presents a novel refactoring approach that effectively solves these two problems. Our approach infers a concise set of semantics-preserving transformation rules from two versions of a single class. Unlike prior approaches that detect only simple structural refactorings, our algorithm can infer general composite refactorings and is more than 97 % accurate on average. We demonstrate the effectiveness of our approach by automatically upgrading more than 80K lines of the unit testing code of four open-source Java applications to use the latest version of the popular JUnit testing framework.

We show how new syntactic forms and static analysis can be added to a programming language to support abstractions provided by libraries. Libraries have the important characteristic that programmers can use multiple libraries in a single program. Thus, any attempt to extend a language’s syntax and analysis should be done in a composable manner so that similar extensions that support other libraries can be used by the programmer in the same program. To accomplish this we have developed an extensible attribute grammar specification of Java 1.4 written in the attribute grammar specification language Silver. Library writers can specify, as an attribute grammar, new syntax and analysis that extends the language and supports their library. The Silver tools automatically compose the grammars defining the language and the programmer-selected language extensions (for their chosen libraries) into a specification for a new custom language that has language-level support for the libraries. We demonstrate how syntax and analysis are added to a language by extending Java with syntax from the query language SQL and static analysis of these constructs so that syntax and type errors in SQL queries can be detected at compile-time. 1.

Abstract. In this paper we introduce the concept of Technical Space (TS) to refer to technologies at a higher level of abstraction. Some technical spaces can be easily identified, e.g. the XML TS, the DBMS TS, the programming languages TS, the OMG/MDA TS, etc. As the spectrum of such available technologies is rapidly broadening, the necessity to offer clear guidelines when choosing practical solutions to engineering problems is becoming a must. The purpose of our work is to figure out how to work more efficiently by using the best possibilities of each technology. To do so, we need a basic understanding of the similarities and differences between various TSs, and also of the possible operational bridges that will allow transferring the artifacts obtained in one TS to other TS. The analysis of several technical spaces reveals that they can be perceived in a broader context as model management frameworks, that is, every space is populated with models. An important commonality is that these frameworks are organized according to a three-level architecture based on models, metamodels, and metametamodels. The unified model-based view brings a conceptual foundation to study the possible bridges between spaces. Bridging technical spaces is especially useful when it brings new capabilities not available in a given space. We hope that the presented vision may help us putting forward the idea that there could be more cooperation than competition among alternative technologies. 1