universal-server.lfe

(defmodule universal-server
  (export all))

(defun universal-server ()
  (receive
    ((tuple 'become f)
     (funcall f))))

(defun factorial-server ()
  (receive
    ((tuple from n)
     (! from (factorial n))
     (factorial-server))))

(defun factorial
  ((0) 1)
  ((n) (* n (factorial (- n 1)))))

(defun run (n)
  (let ((pid (spawn #'universal-server/0)))
    (! pid (tuple 'become #'factorial-server/0))
    (! pid (tuple (self) n)))
  (receive
    (x x)))