HIGH-LEVEL LANGUAGE EXTENSIONS FOR USER-INTERFACE PROGRAMMING

Many user-interface toolkits, screen management facilities and user-interface managements systems (UIMS) have been developed in the last few years for creating user interfaces. These systems, however, normally require the user to learn a new programming language or set of techniques. Extending conventional programming languages has the advantage that the same language can be used for describing both the application and the user interface. In addition, both the application's view of the data and the user's view of the data can be specified by the same type system, in a consistent and elegant way. In this paper, we outline several drawbacks of conventional high-level procedural languages and present extensions to Pascal to facilitate user-interface programming. The goal is to provide a language where the display items, dialogue control rules, application software, concurrent operations, and dynamic program linking can all be easily programmed in the same language, without resorting to an assembler language or another language. The extensions have been used in implementing several microelectronics fabrication systems. Although these are specific applications, the extensions can be helpful in programming textual user interfaces in other application areas, such as process control, manufacturing control and real-time systems.