Although detractors of functional programming sometimes claim that functional programming is too difficult or counter-intuitive for most programmers to understand and use, evidence to the contrary can be found by looking at the popularity of spreadsheets. The spreadsheet paradigm, a first-order subset of the functional programming paradigm, has found wide acceptance among both programmers and end users. Still, there are many limitations with most spreadsheet systems. In this paper, we discuss language features that eliminate several of these limitations without deviating from the first-order, declarative evaluation model. The language used to illustrate these features is a research language called Forms/3. Using Forms/3, we show that procedural abstraction, data abstraction and graphics output can be supported in the spreadsheet paradigm. We show that, with the addition of a simple model of time, animated output and GUI I/O also become viable. To demonstrate generality, we also present an animated Turing machine simulator programmed using these features. Throughout the paper, we combine our discussion of the programming language characteristics with how the language features prototyped in Forms/3 relate to what is known about human effectiveness in programming.

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Spreadsheet languages, which include commercial spreadsheets and various research systems, have proven to be flexible tools in many domain specific settings. Research shows, however, that spreadsheets often contain faults. We would like to provide at least some of the benefits of formal testing and debugging methodologies to spreadsheet developers. This paper presents an integrated testing and debugging methodology for spreadsheets. To accommodate the modeless and incremental development, testing and debugging activities that occur during spreadsheet creation, our methodology is tightly integrated into the spreadsheet environment. To accommodate the users of spreadsheet languages, we provide an interface to our methodology that does not require an understanding of testing and debugging theory, and that takes advantage of the immediate visual feedback that is characteristic of the spreadsheet paradigm.

Spreadsheet languages, which include commercial spreadsheets and various research systems, have proven to be flexible tools in many domain specific settings. Research shows, however, that spreadsheets often contain faults. We would like to provide at least some of the benefits of formal testing and debugging methodologies to spreadsheet developers. This paper presents an integrated testing and debugging methodology for spreadsheets. To accommodate the modeless and incremental development, testing and debugging activities that occur during spreadsheet creation, our methodology is tightly integrated into the spreadsheet environment. To accommodate the users of spreadsheet languages, we provide an interface to our methodology that does not require an understanding of testing and debugging theory, and that takes advantage of the immediate visual feedback that is characteristic of the spreadsheet paradigm.