Not if `plus` is a pointer. Then `plus()` is a conditional branch where the condition can be arbitrarily far away in space (dynamically scoped) and time. That's

Not if `plus` is a pointer. Then `plus()` is a conditional branch where the condition can be arbitrarily far away in space (dynamically scoped) and time. That's why I think invisible indirection is a mistake. (C used to require `(*plus)()`.)