decl flow_control_test : -> Unit
def flow_control_test = {
  if (a < b ||. a == b) && (b < c) then IO.print: x
  elif x < 0 then {
    ; x += 1
    ; IO.print: y
  } else {
    return {}
  }

  while (a > 0) && not: (array.is_empty:) do {
    ; a -= 1
    ; array.pop:
  }

  while x < 10 do x +=. x + 3

  for i in 0--y do {
    ; IO.print: i
  }

  for & i & j in (& 0--y & 0--k) do { // ??
    ; IO.print: 1
    ; IO.print: 2
    ; IO.print: 128
  }

  loop {
    ; y += 1
    if y > 100 then
      break
  }
}