about recursive looping

Recursion is fundamental to the underlying mathematical model of functional programming. Iteration requires mutable state (some form of index counter), and cannot be expressed purely in terms of functions. Stack overflow is avoided by tail-call optimization.

At the most extreme, Church Numerals express even basic arithmetic and numeric values in terms of functions.

 

In iterative languages that don't normally support tail call optimization to limit stack growth a technique called trampolining can be used to minimize stack depth. Generally functional languages support tail call optimization, so stack frames are reused for each call.

-Lee

 

Functional programming emphasize functions over storing explicit state. Using a loop requires state explicit state in the form of an iterator.