ApplBuilder: An Object-Oriented Application Generator Supporting Rapid Prototyping

Abstract

This paper describes an object-oriented application generator, APPLBUILDER, currently being developed in the Mjølner BETA programming environment. APPLBUILDER supports several rapid prototyping styles as well as final development of BETA applications. User interface objects such as dialogs, menus, and windows are designed using direct manipulation graphical editors. Actions behind buttons and menu items are programmed as ''scripts'' in textual editors activated from within a graphical editor. The editors reflect changes in the code directly in an underlying Abstract Syntax Tree (AST) thus saving compilation time. Moreover, generated applications are modularized so that editing, for instance the script for a button, only requires re-compilation of the script itself. An advantage of APPLBUILDER compared to other user-interface design tools such as HyperCard is that APPLBUILDER's scripts are embedded in a general purpose programming language making it possible to avoid calls to external routines written in another language. In addition, APPLBUILDER's ability to work with ASTs instead of textual code skeletons supports reverse engineering.