The WIST Custom Tag Library
The WIST custom tag library provides the base tags necessary to build a web-based spreadsheet where the cell contents are determined by form variables in the row and column headers. It is designed to be extensible to accomodate different implementations of ways to resolve the contents of any given cell, and to be simple enough to hide most of the implementation detail from the end users. There are only a few concepts that it is necessary to understand to build a fully functional WIST.
A WIST is fundamentally an HTML table where the contents of each cell depends upon variables that are set in the row and column headers, and in a central control panel. The simplest implementation of the WIST simply reformats a given URL based upon these parameters, and either retrieves the data or provides the formatted link to the data in each cell of the table.
The most important concept that we use in building the WIST is the idea of a dimension. You can think of a dimension as simply being a type of row or column - a set of parameters that are used to reformat the link in any cell that the row or column intersects. Our concept of a dimension, however, extends beyond the simple limitations of row and column - you can have any number of dimensions intersect to help resolve a cell, change the axis of the table along which a dimension is displayed, turn dimensions on and off, and other things. By thinking in terms of dimensions rather than strictly in terms of rows and columns, we open up whole realms of possibility.