An event language for building user interface frameworks

Abstract

Languages based on the event model are widely regarded as expressive and flexible notations for the specification of interactive graphical user interfaces. However, until now, they have only been used to specify and implement the dialogue control component of user interfaces. This paper presents an extension of the event model. A computable notation, the event language, based on this is used to construct a complete user interface framework. The framework forms the runtime component of a UTMS. The event language allows the modular construction of complex event systems. This is supported by the addition of a tagged addressing mode. Furthermore, the control structure of event handlers is extended with exception management, permitting unspecified events and thereby facilitating the use of predefined building blocks. A general purpose run-time framework for user interfaces has been constructed using the event language. We present the architecture of the presentation component of this framework including the window manager and the I/O model. CR Categories and Subject Descriptors: D.2.2 [Software Engineering]: Tools and Techniques - User Interfaces; F.l.l [Computation by Abstract Devices]: Models of Computation - Automata; 1.3.6 [Computer Graphics]: Methodology and Techniques - Languages General Terms: Languages, Design.