Defining MARTE’s VSL as an Extension of Alf

VSL and Alf are two OMG standards providing a textual notation for complex mathematical expressions and detailed activities respectively. Since these two notations have been designed by separate communities (real-time embedded for VSL and software engineering for Alf), they differ in syntax and semantics. Nevertheless, they clearly exhibit intersections in their form and use cases. The purpose of this article is to demonstrate that an alignment effort between the two languages would be beneficial for both users and tool providers. We show that most of the syntactic constructs introduced in VSL are related to general-purpose concerns (i.e., they are not specific to the real-time domain), most of them being covered by Alf. In this paper, we first identify the subset of VSL which is valuable for the real-time domain, and then propose a way of extending Alf with this subset.