let rec fib =
if n <= 2
then 1
else fib (n - 1) + fib (n - 2)
let rec sum list =
match list with
| head :: tail -> head + sum tail
| [] -> 0
let rec len list =
match list with
| head :: tail -> 1 + len tail
| [] -> 0
let rec mymap f = function
| [] -> []
| x :: xs -> f x::mymap f xs
// clutters the stack
let rec factorial =
match n with
| 0 | 1 -> 1
| _ -> n * factorial (n-1)
// tail recursive version
let factorial n =
let rec tailRecursiveFactorial n acc =
match n with
| 0 -> acc
| _ -> tailRecursiveFactorial (n - 1) (acc * n)
tailRecursiveFactorial n 1
