Similarity Inheritance: A New Model of Inheritance for Spreadsheet VPLs

Although spreadsheets can be argued to be the most widely-used visual programming languages (VPLs) today, most are very limited compared to other VPLs, supporting only a few built-in types and offering only primitive support for code reuse. The inheritance mechanisms of object-oriented programming might seem to offer help for the latter problem, but incorporating these mechanisms in a traditional way would introduce concepts foreign to spreadsheets, such as message passing. In this paper, we present similarity inheritance, a new approach to inheritance that is suitable for seamless integration into the spreadsheet paradigm. We first explain the model independently of any implementation, and then present a prototype implementation in the research spreadsheet VPL Forms/3. We show that bringing inheritance functionality to the spreadsheet paradigm can be done using the widely-understood idea of copy/paste. Further, we show why the approach requires the presence of a live, visual environment.