Because I can :-P

Here's some code to calculate factorial in JavaScript. It is..inefficient. But in some sense it is very simple, since I've just reduced it down to function calls and the Peano Axioms.

Please note how helpfully I've indented and the wonderful choices of variable names...

\n  function (builder) {\n    return function (s) {\n      return function (p) {\n        return function (n) {\n          return builder(builder)(s)(p)(n);\n        }\n      }\n    }\n  }(\n    function (recurse) {\n      return function (s) {\n        return function (p) {\n          return function (n) {\n            if (0 == n)\n              return 1;\n            else\n              return function (builder) {\n                return function (n) {\n                  return function (m) {\n                    return builder(builder)(n)(m);\n                  }\n                }\n              }(\n                function (recurse) {\n                  return function (n) {\n                    return function (m) {\n                      if (0 == n)\n                        return 0;\n                      else\n                        return function (builder) {\n                          return function (n) {\n                            return function (m) {\n                              return builder(builder)(n)(m);\n                            }\n                          }\n                        }(\n                          function (recurse) {\n                            return function (n) {\n                              return function (m) {\n                                if (0 == n)\n                                  return m;\n                                else\n                                  return s(recurse(recurse)(p(n))(m));\n                              }\n                            }\n                          }\n                        )(\n                          m\n                        )(\n                          recurse(recurse)(p(n))(m)\n                        );\n                    }\n                  }\n                }\n              )(\n                n\n              )(\n                recurse(recurse)(s)(p)(p(n))\n              );\n          }\n        }\n      }\n    }\n  )(\n    function (n) { return n + 1 }\n  )(\n    function (n) { return n - 1 }\n  )(\n    5  // This parameter controls which factorial we compute\n  );\n

(Unfortunately I seem to hit too much recursion when computing 8!, I wonder why??)

Cheers,
Ben

\n (((((lambda ( builder )\n (lambda ( s )\n (lambda ( p )\n (lambda ( n )\n ((((builder builder) s) p) n))))) (lambda ( recurse )\n (lambda ( s )\n (lambda ( p )\n (lambda ( n )\n (if (= 0 n)\n 1\n ((((lambda ( builder )\n (lambda ( n )\n (lambda ( m )\n (((builder builder) n) m)))) (lambda ( recurse )\n (lambda ( n )\n (lambda ( m )\n (if (= 0 n)\n 0\n ((((lambda ( builder )\n (lambda ( n )\n (lambda ( m )\n (((builder builder) n) m)))) (lambda ( recurse )\n (lambda ( n )\n (lambda ( m )\n (if (= 0 n)\n m\n (s (((recurse recurse) (p n)) m))))))) m)\n\t\t\t (((recurse recurse) (p n)) m))))))) n)\n\t\t\t ((((recurse recurse) s) p) (p n)))))))))\n\t\t\t (lambda ( n )\n (+ n 1))) (lambda ( n )\n (- n 1))) 5)\n

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