[kazinator]

The author may be eloquent, but unfortunately calls imperative operators, like while, "functions".

[layer8]

Imperative code is a function from one program state to another.

[kazinator]

That concept is not reified in the imperative language in any meaningful way. There is no actual function from the program state, to the next state as a language construct. Even if there were, it would be in a different category from the while loop and its ilk.