Lua 错误：期望 '<eof>'

我遇到了一个无法解决的错误。每次运行脚本时都会出现以下错误：

bios:14: [string "Digger"]:35: 期望 '<eof>'

write("X:")
x = read()
write("Y:")
y = read()
write("Z:")
z = read()
for zi=0, z, 1 do
    for xi=0, x, 1 do
        for yi=0, y, 1 do
            turtle.dig()
            turtle.forward()
        end
        if xi < x then
            if xi % 2 then
                turtle.turnLeft()
                turtle.dig()
                turtle.forward()
                turtle.turnLeft()
            else
                turtle.turnRight()
                turtle.dig()
                turtle.forward()
                turtle.turnRight()
            end
        end
    end
    if y % 2 == 1 then
        turtle.turnRight()
        for back=0, y, 1 do
            turtle.forward()
        end
        turtle.turnRight()
    end
end

虽然我已经在互联网上找到了出错的地方，但我没有找到错误。你能告诉我出了什么错误吗？