Introduction

Letlang provides only one loop mechanism, the tailrec function.

A tail recursive function returns either:

• final[value] to exit the loop
• recurse[args...] to keep iterating with new arguments

Example

tailrec len<T>(items: list<T>, acc: int) -> int {
  match items {
    [] => final[acc],
    [_ | tail] => recurse[tail, acc + 1],
  };
}