I need to write an ROI calculator as part of some demos at Nexaweb. I may as well show the process. Since this is not intended to be a robust mission critical application, I am really looking for how easy it is to go from concept to development and to iterate (since I am sure there we won't get it right the first time)

So let's start with the ROI logic in - surprise - an Excel spreadsheet. (Excel being where many of these rules and formulas are created.) .

Here is the spreadsheet.

Since Nexaweb technologies is based on declarative XML (XAL), the approach I decided to take (with the help of Fred Mikkelsen) was to use Excel itself to generate the basic XAL markup which would in turn form the basis of the Nexaweb ROI calculator (without the formulas).

So, while formulas would not be preserved, cells and tabs would be. The rest of the development then would be to implement the formulas (such as sum) and spread sheet like functionality (such as auto update when a user exits a cell) with Javascript (added to Nexaweb platform as MCO's) and Nexaweb event handling and UI update technologies.