Tkinter 和 Tic-Tac-Toe 的问题

Question

我正在使用 Tkinter 编写一个井字游戏。当一个用户获胜时，会出现一个带有重新启动按钮的顶级窗口，该窗口必须重新启动程序，但是当我单击它时收到意外错误。我知道我的获胜者检查功能很愚蠢，但我可以用我目前的知识水平写一个更好的。错误信息：

Exception in Tkinter callback

Traceback (most recent call last):

  File "C:\Users\Eldiiar Raiymkulov\AppData\Local\Programs\Python\Python36-32\lib\tkinter\__init__.py", line 1699, in __call__

    return self.func(*args)

  File "C:\Users\Eldiiar Raiymkulov\Desktop\xo2.py", line 62, in <lambda>

    command=lambda x=x, y=y: clicked(y, x)))

  File "C:\Users\Eldiiar Raiymkulov\Desktop\xo2.py", line 15, in clicked

    isWinner(char)

  File "C:\Users\Eldiiar Raiymkulov\Desktop\xo2.py", line 46, in isWinner

    topMessage(char)

  File "C:\Users\Eldiiar Raiymkulov\Desktop\xo2.py", line 30, in topMessage

    topButton = Button(top, text="Restart", command=restart(root))

NameError: name 'root' is not defined

这是代码：

from tkinter import *

turn = True

btns = None

def clicked(y, x):

    global turn, btns

    char = ""

    if turn:

        char = "X"

    else:

        char = "O"

    btns[y][x].config(text=char,

                      state=DISABLED)

    isWinner(char)

    turn = not turn

def restart(root):

    global turn

    turn = True

    root.destroy()

    main()

def topMessage(char):

    global root

    top = Toplevel()

    top.title("Congratulations!")

    topText = Label(top, text=f"{char} is a winner!")

    topButton = Button(top, text="Restart", command=restart(root))

    topText.grid(row=0)

    topButton.grid(row=1)

def isWinner(char):

    global root

另外，如果您对 isWinner 函数有任何更明智的建议，可以与我分享吗？