[skybrian]

A Turing machine has an unlimited tape. You can’t emulate it with a fixed amount of memory.

It’s mostly a theoretical issue, though, because all real computer systems have limits. It’s just that in languages that assume unlimited memory, the limits aren’t written down. It’s not “part of the language.”

[dnautics]

If we get REALLY nitpicky, zig currently (but not in the future) allows unbounded function recursion with "theoretically" assumes unlimited stack size, so it's potentially "still technically theoretically turing complete". For now.

[chongli]

What about IO? Just because I have a statically allocated program with a fixed amount of memory doesn’t mean I can’t do IO. My fixed memory can just be a cache / scratchpad and the unlimited tape can work via IO (disk, network, etc).

[skybrian]

Yes, good point.