Software Language Evolution

Like any software artifact, software languages are subject to evolution. When a software language evolves, existing language elements may no longer conform to the evolved language. To prevent loss of information, existing elements need to be migrated. Coupled evolution automates the migration of existing elements by attaching a migration specification to the evolution of a language definition. Software language evolution affects different technological spaces such as dataware, grammarware, XMLware, and modelware. In each technological space, different coupled evolution approaches have been proposed. However, it is largely unknown how these approaches relate to each other. To address this, we perform a systematic literature survey on coupled evolution approaches. We derive a feature model focused on determining commonalities and differences between approaches from different technological spaces. In this chapter, we present the application of the feature model and the interpretation of its results, within each technological space as well as across technological spaces. We address specifics within spaces, avenues for future research, portability of techniques across spaces, and correlated features. 2.1 I N T R O D U C T I O N Various areas of computer science deal with information stored in artefacts (or elements). For example, programs store the description of an application, databases store application data and an XML document can store the configuration of an application. Together, we refer to these elements as software [Kleppe, 2008]. Common to all software is that the stored information is structured to some format. Programs conform to a grammar, databases conform to a data model and XML documents conform to a schema. The format of a piece of software, or more generally of a collection of software is described by the software language. We say that software elements conform to a software language, when the software follows the structure outlined in the language. A software language is needed for the software elements to be understood, to be extended or to be processed automatically. Breaking conformance generally has as consequence