Can I release an Excel Workbook with VBA code under the GPL v3?

Question

This is my first foray into the open source world. I've got a Microsoft Excel workbook that I have some custom VBA modules in that I want to distribute under the GPL v3. I can't find much discussion on the philosophy of using the GPL with Excel, but I think it would be kind of treating it like a plugin.

Excel is independent, but my particular "plugin" requires my independent worksheets and code to add it's a new benefit. Therefore, even though Excel is a paid program, my VBA script and workbook would be covered, right? Am I misinterpreting the GPL? Would that run afoul of any other intellectual property issue?

Answer 1

Mandatory disclaimer: I am not a lawyer.

As far as I understand it, GPL allows your program to depend on non-GPL "system libraries", which are:

The “System Libraries” of an executable work include anything, other than the work as a whole, that (a) is included in the normal form of packaging a Major Component, but which is not part of that Major Component, and (b) serves only to enable use of the work with that Major Component, or to implement a Standard Interface for which an implementation is available to the public in source code form. A “Major Component”, in this context, means a major essential component (kernel, window system, and so on) of the specific operating system (if any) on which the executable work runs, or a compiler used to produce the work, or an object code interpreter used to run it.

(quoted from GPL 3. GPL 2 has a slightly different definition, but the spirit is the same).

In this case, as long as you are not shipping Excel, but assuming the end-user already has Excel and would just install your plugin to provide additional functionality, Excel would be your "system library", and the fact it isn't licensed under GPL should be fine.