IFS: a software tool to build end user systems

The salient features of IFS (Interpretive Frame System), a tool for building end-user systems with sophisticated, yet easy to use interfaces, are reviewed. IFS promotes the idea of separating design programming from computational programming. It provides a programming language and environment suitable for implementing the design aspects of an application system, and its task structure and user interface. Domain-specific computations are assumed to be carried out by other tools and processes. The language provides powerful constructs for executing and interfacing with application-specific subroutines and processes for such computations. By restricting the program interface at the subroutine and process level, IFS both makes it easy to reuse existing tools and encourages the construction of new tools reusable in other contexts. Being able to directly execute subroutines for critical computations, application systems can achieve their required levels of efficiency or robustness. More important, however, is the ability to quickly prototype system designs and user interfaces and to allow early involvement of users in the system development cycle, ensuring accurate requirements