There’s a really cool diff class hosted by Google here:
http://code.google.com/p/google-diff-match-patch/
I’ve used it before on a few web sites, but now I n
My suggestion would be that whatever you do you wrap it in a COM wrapper. VBA deals best with COM objects so you could compile as a .NET Component then expose as a COM object using the interop functionality of .NET.
As an alternative you could also look into using Windows Scripting Host objects to execute a Javascript File and return you the result.