I have written an application as an Excel XLSM file. I would now like to package it for commercial sale. My goal is to be transparent to the user, and the same time protect my intellectual property. I know that I can compile it into an EXE, but my preference would be to call it from an Excel add-in.
The user would select actions from the ribbon that would copy input from his worksheet into my system, and then call VBA subroutines which perform the underlying data manipulations and then display results sheets.
Can an Excel XLSM be called from an add-in? Can its content be secured? If not, could an EXE be called by in add-in? Or, is there a better way?