Unisys is currently working to lay a foundation to move the state-of-practice further along the model-based maturity scale described earlier. Unisys is acquiring and producing a technology base to provide a machine readable and processable representation of domain models in a form which domain-specific tools may directly utilize and manipulate. The Reusability Library Framework[SWT89] (RLF), a step along the path leading to an organon, is a set of Ada knowledge-based tools (semantic network and rule-based systems that can be used in concert) to support the definition and manipulation of domain models.
The RLF is currently targeted to the production of domain-specific, knowledge-based[MC89] software library systems where the engineer is supported in his or her production of software systems using software assets contained in the library. Domain models are captured in sophisticated semantic networks which capture the crucial objects, operations on objects and relationships between objects within the domain. Library assets are catalogued and stored according to this domain model. In addition, the human engineer is aided by a rule-based inference system which provide guidance in exploring and understanding the domain model and the assets within the library. Domains addressed to date include Anti-Submarine Warfare (ASW), User Interfaces (in particular the use of Ada/Xt) and Ada benchmarks.
The RLF has also been used to develop a model-based tool utilization assistant (TUA) for the domain of document preparation. An early version of the RLF was used to produce an Ada Unit Test Assistant (Gadfly) [WSS+88] which contained a model of test heuristics and generated test plans based on parsing of Ada units and interaction with a human test engineer.
Broad objectives of the RLF project include:
Recently, an X Windows-based graphical browser interface was developed for librarian applications built on top of the RLF.