in my model it's the platform job to handle the user input and your program output you just write your function and the platform calls your program for example f(time,input_data,key_a,key_b,key_c,...) . if you are very very patient and don't care about the program length you can just compute every output of your program for every possible input. according to [this](https://web.archive.org/web/20230505022436/http://page.mi.fu...) paper a single loop and four basic arithmetic operation is enough to simulate a turing machine so my idea was that to unroll the loop and my conjecture is that we don't need the loop and only four operations is enough to compute all total computable functions