--?   print('snap', State.screen_top1.line, State.screen_top1.pos, State.screen_top1.posB, State.cursor1.line, State.cursor1.pos, State.screen_bottom1.line, State.screen_bottom1.pos)

--?   print('snap', State.screen_top1.line, State.screen_top1.pos, State.cursor1.line, State.cursor1.pos, State.screen_bottom1.line, State.screen_bottom1.pos)

--?   print('snap', State.screen_top1.line, State.screen_top1.pos, State.cursor1.line, State.cursor1.pos, State.screen_bottom1.line, State.screen_bottom1.pos)

    log(2, os.date('%Y/%m/%d/%H-%M-%S')..' assertion failure: '..tostring(#State.lines)..' ~= '..tostring(#State.line_cache))

    log(2, os.date('%Y/%m/%d/%H-%M-%S')..(' line_cache is out of date; %d when it should be %d'):format(#State.line_cache, #State.lines))

  State.cursor_x = nil
  State.cursor_y = nil

  if #State.lines ~= #State.line_cache then
    print(('line_cache is out of date; %d when it should be %d'):format(#State.line_cache, #State.lines))
    assert(false)
  end