I only mention python because people were asking about it. There are really two unrelated questions here: 1) How does a computer start executing your code? 2)

I only mention python because people were asking about it. There are really two unrelated questions here: 1) How does a computer start executing your code? 2) What kind of abstractions does a programming language provide? Having anything other than a function as a top level most likely implies an abstraction. The second question is pretty much irrelevant when you are talking about interpreted languages. These aren't programs at all from the perspective of the CPU. JIT is a different story, and one that I know very little about on a technical level. What happens when pypy generates some native code? Does it generate a function and call it? Does it have some other convention? I have no idea.