RSL-IL: An interlingua for formally documenting requirements

Despite being the most suitable language to communicate requirements, the intrinsic ambiguity of natural language often undermines requirements quality criteria, specially clearness and consistency. Several proposals have been made to increase the rigor of requirements representations through conceptual models, which encompass different perspectives to completely describe the system. However, this multi-representation strategy warrants significant human effort to produce and reuse such models, as well as to enforce their consistency. This paper presents RSL-IL, a Requirements Specification Language that tackles the requirements formalization problem by providing a minimal set of constructs. To cope with the most typical Requirements Engineering concerns, RSL-IL constructs are internally organized into viewpoints. Since these constructs are tightly integrated, RSL-IL enables the representation of requirements in a way that makes them formal enough for being tractable by a computer. Given that RSL-IL provides a stable intermediate representation that can improve the quality and enables requirements reuse, it can be regarded as a requirements interlingua. Also, RSL-IL can be used as a source language within the context of model-to-model transformations to produce specific conceptual models. To illustrate how RSL-IL can be applied in a real project, this paper provides a running example based on a case study.