fib_loop.io

fib := method(n,
  if (n == 1 or n == 2, return 1)

  p1 := 1
  p2 := 1
  for (i, 3, n,
    temp := p1
    p1 := p1 + p2
    p2 := temp)
  return p1
)

assert := method(
  actual := call sender doMessage(call message argAt(0))
  expect := call sender doMessage(call message argAt(1))
  if (actual != expect, Exception raise("Assertion failed: Expect #{expect} but got #{actual}" interpolate))
)

assert(fib(1), 1)
assert(fib(2), 1)
assert(fib(3), 2)
assert(fib(4), 3)
assert(fib(5), 5)
assert(fib(6), 8)

fib_recursive.io

fib := method(n,
  myself := call activated
  if (n == 1 or n == 2, 1, myself(n-1) + myself(n-2))
)

assert := method(
  actual := call sender doMessage(call message argAt(0))
  expect := call sender doMessage(call message argAt(1))
  if (actual != expect, Exception raise("Assertion failed: Expect #{expect} but got #{actual}" interpolate))
)

assert(fib(1), 1);
assert(fib(2), 1);
assert(fib(3), 2);
assert(fib(4), 3);
assert(fib(5), 5);
assert(fib(6), 8);