FORM FORMULA - A VISUAL PROGRAMMING PARADIGM FOR USER-DEFINABLE USER INTERFACES/

In traditional user interfaces, syntax (visual attributes) and semanti cs (behavioral aspects) are separate, and the semantics are defined in a programming language. Thus, nonprogrammers-that is, the end users t hemselves-cannot easily define user-interface semantics. In many appli cations, however, the interface for one group of users is best designe d by users belonging to another group. For example, in educational app lications, teachers should be able to construct the user interface for students, and administrators should be able to build user interfaces for teachers. To overcome this difficulty, the authors propose using a visual programming language for semantic specifications. In their for m/formula paradigm, the user first specifies the interface layout (for m) using a graphics editor that recognizes shapes, handwriting, and ge stures. The semantics of the form is defined by a directed graph of ne sted boxes (formula). A combination of forms and formulas is used to d efine graphic user interfaces as well as database queries. The authors have incorporated the form/formula paradigm into the Hyperflow langua ge and implemented it on the PenPoint operating system for educational applications. To explain the paradigm and demonstrate its utility for user-definable user interfaces, the authors include three examples: c onverting between Fahrenheit and Celsius, designing an arithmetic work sheet, and querying student records.