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. 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.