initialise-binding scope
  (collateral
     (bind
        ("fib",
         function abstraction
           (scope
              (collateral
                 (map
                    ( ),
                  map
                    ( ),
                  map
                    ( ),
                  bind
                    ("n",
                     allocate-initialised-variable
                       (integers,
                        checked head
                          given))),
               sequential
                 (if-else
                    (is-less-or-equal
                       (assigned
                          (bound
                             ("n")),
                        decimal-natural
                          ("1")),
                     scope
                       (collateral
                          (map
                             ( )),
                        return assigned
                          (bound
                             ("n"))),
                     null),
                  return int-add
                    (handle-return apply
                       (bound "fib",
                        list
                          (integer-subtract
                             (assigned
                                (bound
                                   ("n")),
                              decimal-natural
                                ("1")))),
                     handle-return apply
                       (bound "fib",
                        list
                          (integer-subtract
                             (assigned
                                (bound
                                   ("n")),
                              decimal-natural
                                ("2"))))))))),
      map
        ( ),
      map
        ( )),
   sequential
     (null,
      scope
        (bind
           ("n",
            allocate-initialised-variable
              (integers,
               0)),
         while
           (is-less
              (assigned
                 (bound
                    ("n")),
               decimal-natural
                 ("5")),
            sequential
              (scope
                 (collateral
                    (map
                       ( )),
                  print handle-return apply
                    (bound "fib",
                     list
                       (assigned
                          (bound
                             ("n"))))),
               assign
                 (bound "n",
                  int-add
                    (1,
                     assigned bound
                       "n")))))))