Perspectives to promote modularity, reusability, and consistency in multi-language systems

In modern software systems, software modellers often use different modelling languages and multiple views to describe the characteristics of a complex system. This multi-language system allows modellers to express a specific system characteristic with the most appropriate modelling languages and notations. With the proliferation of independently developed and continually evolving modelling languages, it becomes more challenging to reuse or combine multiple languages in a multi-language modelling environment. In this paper, we present a framework for the specification and development of multi-language systems based on perspectives to promote modularity in language reuse, inter-language consistency, and combination of languages. A perspective groups different languages for a modelling purpose and defines the role of each participating language. Furthermore, a perspective defines composite actions for building a consistent multi-model system and maintaining the links between different model elements. These actions are specified by re-exposing, combining, or redefining existing language actions (e.g. create an operation in a class diagram model) offered by the languages that the perspective reuses. The aim of this framework is to streamline the combination of multiple languages in a system and allow the perspective designer to focus only on specifying relationships between different languages. A generative approach then ensures appropriate language registration and model consistencies, hence freeing the perspective designer from the error-prone implementation of the consistency mechanism and simplifying the modular combination of different languages. We illustrate our approach with a perspective aimed at requirement elicitation and specification that combines five different languages, i.e. class diagrams, use case diagrams, collaboration diagrams, use case maps, and a domain-specific modelling language.