SHF Small: Language Support for Variation Maintenance

变更管理是软件工程的一个重要组成部分。许多现有的软件项目已经可以生成大量不同的程序，这些程序运行在不同的平台上，并提供不同的功能集。对软件产品线和面向功能的软件开发的研究已经为大规模可配置软件的开发提供了过程和工具，这表明软件系统的可变性只会继续增长。目前一个很大程度上未解决的问题是如何系统地转换变体表示来支持变体的创建、重构和迁移，以及对富含变体的软件存储库的分析和查询。本研究的目的是探讨变奏结构的系统转换，并为其提供语言支持。采用以下技术方法。首先，收集变型编程任务将为理解变型转换的性质和程度提供基础，并且汇编此类任务的目录将有助于变型语言的设计、评估和比较。其次，转换选择演算的语法和语义的定义，扩展了具有计算特征的（表征）选择演算，将支持对变分规划的形式性质的研究。第三，变分类型系统的发展有助于表征不同类型的变分结构的变化和演化。此外，变体模块系统的开发将在选择演算表示的复杂范围和绑定问题所需的低级细节和变体的更高级的声明性视图之间提供接口。最后，针对变化编程的领域特定嵌入式语言的设计将允许对软件工件中变化结构的转换进行简单的描述。它还支持变异变换的实验。由于这项研究的范围超出了专业软件，也涵盖了最终用户编程系统，如电子表格，因此所开发的方法将适用于各种各样的环境，从而可以使数百万用户以更系统的方式处理变化。

Managing variation is an important part of software engineering. Many existing software projects can already generate a huge number of distinct programs that run on different platforms and provide different feature sets. Research on software product lines and feature-oriented software development has provided processes and tools for the development of massively configurable software, suggesting that the variability of software systems will only continue to grow. A currently largely unsolved problem is how to systematically transform variation representations to support the creation, refactoring, and migration of variation, as wall as the analysis and querying of variation-rich software repositories. The objective of this research is to investigate the systematic transformation of variation structures and develop language support for it. The following technical approach is pursued. First, gathering variation programming tasks will provide a basis for the understanding of the nature and extent of variation transformations, and assembling a catalog of such tasks will aid the design, evaluation, and comparison of variation languages. Second, the definition of the syntax and semantics of a transformational choice calculus, which extends the (representational) choice calculus with computational features, will support the investigation of formal properties of variation programming. Third, the development of a variation type system facilitates the characterization of different kinds of changes and evolutions of variational structures. Moreover, the development of a variation module system will provide an interface between low-level details required by the intricate scoping and binding issues of the choice calculus representation and a more high-level, declarative view of variations. Finally, the design of a domain-specific embedded language for variation programming will allow the easy description of transformations of variation structures in software artifacts. It also supports the experimentation with variation transformations. Since the scope of this research extends beyond professional software and covers also end-user programming systems, such as spreadsheets, the developed methods will be applicable in a wide variety of contexts and can thus empower millions of users to handle variation in a more systematic way.