An extended spreadsheet paradigm for data visualisation systems, and its implementation
Bibliography: leaves 139-144.
We describe a data visualisation system which uses spreadsheets as its user interface metaphor. Similar systems implemented in the past were hampered by the contradiction between an imperative formula language and the declarative spreadsheet framework. We have analysed spreadsheets from a data visualisation point of view, and built a system that is an improvement over past efforts to combine spreadsheets and data visualisation. Our prototype combines the following three techniques: we store lists of values in each spreadsheet cell; we use the functional programming language Scheme as the formula language and we make use of lazy evaluation. The novel combination of these techniques makes our system consistently declarative in nature, and gives it several advantages such as small, uncluttered visual programs, the ability to deal with arbitrarily large datasets and the use of advanced functional language features.