So like months and years? On every project I’ve worked on, the programmers conception of the requirements evolves until the minute they stop working on it. And they only understand the part they worked on, not the whole thing
The discussion is not about understanding "requirements".
A piece of software is a set of instructions that tell a computer how to do something. We use languages like C, Python, Haskell and Lisp to describe what to do in ways that avoid as much ambiguity as possible.
The question is: if you used a natural (human) language, how much confusion would (a) the putative GPT-3000 (b) another programmer (c) a compiler/interpreter incur when trying to understand your instructions?
