external function PutNum(n).
external function PutChar(c).

Function Fib(n),
  if n <= 1,
      return n.
  !
  return Fib(n - 1) + Fib( n- 2).
!

{print the 10th fibonacci number}
set tmp to PutNum(Fib(10)).

{we print 10 because 10 is the ascii code for newline}
change tmp to PutChar(10).