Stateflow to Tabular Expressions
Neeraj Kumar Singh, Mark Lawford, T. S. E. Maibaum, Alan Wassyng · 2015
Stateflow is a visual tool that is used extensively in industry for designing the reactive behaviour of embedded systems. Stateflow relies on techniques like simulation to aid the user in finding flaws in the model. However, simulation is inadequate as a means of detecting inconsistencies and incompleteness in the model. Tabular Expressions (function tables) have been used successfully in software development for more than thirty years. Tabular expressions are also visual representations of functions, but include the important properties of completeness and disjointness. In other words, a tabular expression is well-formed only when the input domain is covered completely (completeness), and when there is no ambiguity in the behaviour described by the tabular expression (disjointness). The goal of our work is to use the completeness and disjointness properties of well-formed tabular expressions to aid us in establishing those properties in Stateflow models. From the Stateflow models, we generate a new kind of tabular expression that includes extended output options. We use the informal Stateflow semantics from MathWorks documentation as the basis for generating our tabular expressions. The generated tabular expressions are then used to guarantee completeness and disjointness. We provide a transformation algorithm that we plan to implement in a tool to automatically generate tabular expressions from Stateflow models.