Thesis (M.S.)--Rutgers University, 2007. / "Graduate Program in Computer Science." Includes bibliographical references (p. 46).

In the experimental ITER fusion reactor, currently under construction in Cadarache, France, components close to the plasma will get activated and contaminated over time. Therefore, these components will need to be maintained remotely in a so called hot cell facility. The maintenance will be executed according to step-by-step procedures, with every procedure meticulously validated and formally described in an Operation Sequence Description (OSD). To support formal validation, OSDs are to be captured in an ITER-dedicated Structured Language (SL), a form of domain specific programming language. The Remote Handling Study Centre (RHSC), located at FOM institute DIFFER, Nieuwegein, The Netherlands, has an ITER Remote Handling Control Room representative setup which connects to a virtual ITER Hot Cell back-end environment. In this setup, Remote Handling maintenance scenarios and procedures can be tested under realistic conditions. In this thesis, a Structured Language for ITER maintenance is proposed, implemented as a prototype to capture several realistic operational sequences from existing projects, and integrated in the RHSC workflow. The Structured Language programs are converted to schedulable tasks, by inferring their resource usage and time duration from the structured task descriptions. These tasks are then scheduled using a proposed set of scheduling heuristics. The resulting schedule is subsequently submitted to many simulated executions, with random variation in the execution time of individual tasks. The variation that is applied in the execution time, is based on representative task execution times was measured for a recent and repetitive set of maintenance tasks performed at JET. It is shown that inserting a certain amount of slack in the schedule improves its robustness. ITER maintenance scheduling should account for uncertainty by including slack in the resulting planning.

In recent years, metadata-driven software development has gained prominence. In this implementation model, various application concerns are provided as third-party frameworks and libraries that the programmer configures through metadata, such as XML configuration files or Java annotations. Metadata-driven software development is a special case of declarative programming: metadata serves as a domain-specific language that the programmer uses to declare various concerns, whose implementation is provided by an elaborate ecosystem of libraries and frameworks that serve as pre-defined application building blocks. Examples abound: transparent persistence mechanisms facilitate data management; security frameworks provide access control and encryption; unit testing frameworks provide abstractions for implementing and executing unit tests, etc. Metadata-driven software development has been particularly embraced in enterprise computing as a means of providing standardized solutions to common application scenarios. Despite the conciseness and simplicity benefits of metadata-driven software development, this implementation model introduces a unique set of reuse and evolution challenges. In particular, metadata is not reusable across application modules, and program evolution causes unsafe discrepancies between the main source code and its corresponding metadata. The research described in this dissertation addresses five fundamental problems of metadata-driven software development: (1) bytecode enhancements that transparently introduce concerns hinder program understanding and debugging; (2) mainstream enterprise metadata formats are hard to understand, evolve, and reuse; (3) concerns declared via metadata cannot be reused when source-to-source compiling emerging languages to mainstream ones; (4) metadata correctness cannot be automatically ensured as application source code is being refactored and enhanced; and (5) lacking built-in metadata, JavaScript programs can be enhanced with additional concerns only through manual source code changes. The research described in this dissertation leverages domain-specific languages and automated code generation to enable effective reuse and safe evolution in metadata-driven software development. The specific innovations that address the problems outlined above are as follows: (1) a domain-specific language (DSL) describing bytecode enhancement that facilitates the understanding and debugging of additional concerns; (2) a novel metadata format expressed as a DSL that is easier to author, understand, reuse, and maintain than existing metadata formats; (3) automated metadata translation that enables effective reuse of target language additional concerns from source-to-source compiled source language programs; (4) metadata invariants---a new abstraction for expressing and verifying metadata coding convention; and (5) a new approach to declaratively enhancing JavaScript programs with additional concerns. / Ph. D.

The task of implementing a programming language is a task that entails a great deal of work. Yet much of this work is similar for different programming languages: most languages require, e.g., parsing, name resolution, type-checking, and optimization. When implementing domain-specific languages (DSLs) the reimplementation of these largely similar tasks seems especially redundant. A number of approaches exist to alleviate this issue, including embedded DSLs, macro-rewriting systems, and more general systems intended for language implementation. However, these tend to have at least one of the following limitations: They present a leaky abstraction, e.g., error messages do not refer to the DSL but rather some other programming language, namely the one used to implement the DSL. They limit the flexibility of the DSL, either to the constructs present in another language, or merely to the syntax of some other language. They see an entire language as the unit of composition. Complete languages are extended with other complete language extensions. Instead, this thesis introduces the concept of a syntax construction, which represents a smaller unit of composition. A syntax construction defines a single language feature, e.g., an if-statement, an anonymous function, or addition. Each syntax construction specifies its own syntax, binding semantics, and runtime semantics, independent of the rest of the language. The runtime semantics are defined using a translation into another target language, similarly to macros. These translations can then be checked to ensure that they preserve binding semantics and introduce no binding errors. This checking ensures that binding errors can be presented in terms of code the programmer wrote, rather than generated code in some underlying language. During evaluation several limitations are encountered. Removing or minimizing these limitations appears possible, but is left for future work / Att implementera ett programmeringsspråk är ett mycket arbetstungt åtagande. Detta trots att mycket av det som behöver göras inte skiljer sig särskilt mycket mellan olika språk, de flesta behöver exempelvis parsning, namnupplösning, typcheckning och optimering. För ett domänspecifikt programmeringsspråk (DSL) är denna upprepning ännu mer tydlig. Det finns ett antal olika metoder för att hantera detta, exempelvis embeddade DSLer, macro-system, och mer generella system för programspråksimplementation. Dessa tenderar dock att ha en eller flera av följande begränsningar: De abstraktioner som introduceras "läcker", felmeddelanden kan exempelvis referera till abstraktioner i ett annat programmeringsspråk, nämligen det som användes för att implementera DSLet. DSLet som implementeras blir begränsat, antingen till vad som finns i implementationsspråket, eller till implementationsspråkets syntax. Ett DSL ses som den minsta hela beståndsdelen i systemet. Om delar av språket ska återanvändas eller inkluderas i ett annat måste hela språket följa med. Denna avhandling introducerar istället syntaxkonstruktioner som minsta beståndsdel. En syntaxkonstruktion representerar en enskild del av ett språk, exempelvis en if-sats, en anonym funktion, eller addition. Varje syntaxkonstruktion definierar sin egen syntax, bindningssemantik och exekveringssemantik, utan referenser till språket som helhet. Exekveringssemantiken liknar en macro, den uttrycks som en översättning till ett implementationsspråk. Tack vare att bindningssemantiken är specifierad kan vi sedan kontrollera översättningen så att den inte kan introducera bindningsfel. Detta medför att felmeddelanden kan referera enbart till kod som programmeraren faktiskt skrev, istället för genererad kod i implementationsspråket. Evalueringen påvisar flera begränsningar med systemet. Begränsningarna tycks lösbara, men detta arbete lämnas till framtiden.

As an extension to the ongoing Coconut (COde COnstructing User Tool) project at McMaster University, we present a Scala library for constructing type-safe domain-specific languages that uses Coconut’s hypergraph-based representation of code (code graphs) as the intermediate representation. Our library automatically produces strongly typed, deeply embedded DSLs given only a minimal specification of the DSL’s value types and primitives. We make extensive use of path-dependent types and implicit argument lookup to construct a type-safe interface on-the-fly, rather than requiring DSL designers to explicitly create a type-safe interface. In this thesis we present our library and demonstrate its utility as both a general-purpose DSL framework and as a suitable platform for continued research on the Coconut project. By giving practical examples of the library in use, we demonstrate both its general utility, and the striking swiftness with which new DSLs may be constructed, especially compared to the previously laborious Haskell DSLs of Coconut. / Thesis / Master of Science (MSc)

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Programs written in managed languages are compiled to a platform-independent intermediate representation, such as Java bytecode. The relative high level of Java bytecode has engendered a widespread practice of changing the bytecode directly, without modifying the maintained version of the source code. This practice, called bytecode engineering or enhancement, has become indispensable in transparently introducing various concerns, including persistence, distribution, and security. For example, transparent persistence architectures help avoid the entanglement of business and persistence logic in the source code by changing the bytecode directly to synchronize objects with stable storage. With functionality added directly at the bytecode level, the source code reflects only partial semantics of the program. Specifically, the programmer can neither ascertain the program's runtime behavior by browsing its source code, nor map the runtime behavior back to the original source code. This research presents an approach that improves the utility of source-level programming tools by providing enhancement specifications written in a domain-specific language. By interpreting the specifications, a source-level programming tool can gain an awareness of the bytecode enhancements and improve its precision and usability. We demonstrate the applicability of our approach by making a source code editor and a symbolic debugger enhancements-aware. / Master of Science

The high demand for building digital libraries by non-experts requires a simplified modeling process and rapid generation of digital libraries. To enable rapid generation, digital libraries should be modeled with descriptive languages. A visual modeling tool would be helpful to non-experts so they may model a digital library without knowing the theoretical foundations and the syntactical details of the descriptive language. In this thesis, we describe the design and implementation of a domain-specific visual modeling tool, 5SGraph, aimed at modeling digital libraries. 5SGraph is based on a metamodel that describes digital libraries using the 5S theory. The output from 5SGraph is a digital library model that is an instance of the metamodel, expressed in the 5S description language (5SL). 5SGraph presents the metamodel in a structured toolbox, and provides a top-down visual building environment for designers. The visual proximity of the metamodel and instance model facilitates requirements gathering and simplifies the modeling process. Furthermore, 5SGraph maintains semantic constraints specified by the 5S metamodel and enforces these constraints over the instance model to ensure semantic consistency and correctness. 5SGraph enables component reuse to reduce the time and efforts of designers. The results from a pilot usability test confirm the usefulness of 5SGraph. / Master of Science