The source code is somewhere on GitHub, but I don't remember where exactly, I tried so many times to write a good spreadsheet. My final goal was to use them to power-up a structured n-dimensional app for storing any kind of data and visualizing it and doing computations like in a normal free-form spreadsheet.
Apple still haven't learnt what Pro actually means yet. I'm not convinced they like professionals using their tablets or even their computers for that matter.
Note to rabid fanboys: don't bother. I use my ipad pro 12.9"s for making money on a daily basis. I know where the faults are.
Like how to add functions etc. This looks promising. https://github.com/myliang/x-spreadsheet/blob/master/src/cor...