In the example in question, the author compares apples to oranges: an imperative iterative Fibonacci print-first-n-fibs vs. a functional recursive Fibonacci ret

In the example in question, the author compares apples to oranges: an imperative iterative Fibonacci print-first-n-fibs vs. a functional recursive Fibonacci return-nth-fib. An imperative recursive Fibonacci return-nth-fib would be far closer to classical mathematical notation. A good way to cut through the ideological BS is to look at how mathematicians write pseudo-code. It's almost always either pure imperative, or imperative with a tiny smattering of OOP/FP stuff (no thicker than you'd see in a sophisticated C project).