H ETS User Guide –

The Heterogeneous Tool Set (HETS) is the main analysis tool for the specification language heterogeneous CASL. Heterogeneous CASL (HETCASL) combines the specification language CASL [6, 28] with CASL extensions and sublanguages, as well as completely different logics and even programming languages such as Haskell. HETCASL (see Fig. 1 for a simple subset) extends the structuring mechanisms of CASL: Basic specifications are unstructured specifications or modules written in a specific logic. The graph of currently supported logics and logic translations (the latter are also called comorphisms) is shown in Fig. 2, and the degree of support by HETS in Fig. 3. With heterogeneous structured specifications, it is possible to combine and rename specifications, hide parts thereof, and also translate them to other logics. Architectural specifications prescribe the structure of implementations. Specification libraries are collections of named structured and architectural specifications. HETS consists of logic-specific tools for the parsing and static analysis of the different involved logics, as well as a logic-independent parsing and static analysis tool for structured and architectural specifications and libraries. The latter of course needs to call the logic-specific tools whenever a basic specification is encountered. HETS is based on the theory of institutions [11], which formalize the notion of a logic. The theory behind HETS is laid out in [20]. A short overview of HETS is given in [25, 26].