Thanks for all the great replies. Notwithstanding my confusion between runtimes and compiled applications, I had a feeling that you would need the source code to recompile.
I took a few semesters of programming in college (C and a little bit of machine code). I do some work with FileMaker, and have become fairly good at scripting. So I think I wouldn’t have too much trouble getting the hang of Xojo.
The challenge is the nature of the program - it’s called FractionAction, and runs on macOS; not sure whether there’s a windows version. It can convert decimal numbers to fractions, reduce fractions, and perform mathematical operations on fractions and show the result as a fraction, rather than a decimal. So the challenge for me would be understanding the math and then programming it. It’s available for free at http://mac.brothersoft.com/fractionaction-x.html.
Anyway, I will keep my fingers crossed that FractionAction will continue to run on macOS for the foreseeable future. It’s a great little utility that I rely on a lot for may day job, which requires me to calculate royalty payments that are based on fractions of fractions.
Tom