Graphical definitions : expanding spreadsheet languages through direct manipulation and gestures

Abstract

Until now, attempts to extend the one-way constraint evaluation model of the spreadsheet paradigm to support complex objects, such as colored circles or user-defined types, have led to approaches featuring either a direct way of creating objects graphically or strong compatibility with the spreadsheet paradigm, but not both. This inability to conveniently go beyond numbers and strings without straying outside the spreadsheet paradigm has been a limiting factor in the applicability of spreadsheets. In this thesis we present a technique that removes this limitation, allowing complex objects to be programmed directly--and in a manner that fits seamlessly within the spreadsheet paradigm--using direct manipulation and gestures. We also present the results of an empirical study which suggests that programmers can use this technique to program complex objects faster and with fewer errors. The graphical definitions technique not only expands the applicability of spreadsheet languages, it also adds to their support for exploratory programming and to their scalability.