Excel also has a feature called VBA which is actually VERY powerful if you catch on how to use it. It is possible to make arbitrarily complex function subroutines in the VB that can be invoked from any cell formula just like the built-in functions. (These functions are written into a code page that gets embedded directly into the worksheet). It is also possible to put any one of a number of windows type control elements, such as command buttons and edit boxes, onto the spreasheet. VBA functions can be provided that respond to events from these controls such as Click(), MouseOver(), Changed().

I have even used the VBA functionality to access the data in a tabular section of the spread sheet and export it as a "source code" format include file to become an initializer in a C code file or an ASM data set.

Michael Karas