if (sys.gvarfind('shell_is_set') = -1)
  gvar(shell_is_set)
  stack &= block.select(BLK_OBJ)
  println('Dim shell')
  println('Set shell = ', (sys.gvarfind('wscript_disable') = -1) ? 'WScript.' : '', 'CreateObject("WScript.Shell")')
  println('')
  block.select(BLK_NOTH)
  println('Set shell = Nothing')
  block.select(_arr.pop(stack))
end