An inversion capability for the PRESTIGE workbench: some basic issues

The PRESTIGE workbench is an integrated CASE (computer-aided software environment) intended to provide full implementation support for Jackson System Development (JSD). JSD is an operational software development method, and thus implementation in JSD is essentially a transformational process. The main objective is to offer a generalized transformational facility that the JSD implementor can apply as desired to suit the needs of any particular implementation scenario, although a default implementation capability is also provided. Many of the transformations required can be automated, and the so-called `inversion´ transformations play a pivotal role in that capability. The author addresses a variety of technical issues that need to be considered in providing a user-controlled inversion facility within the PRESTIGE environment. The issues discussed include schedulerless implementation, rough merges, multiple inversion, buffering, and write inversions