如何使用exec和eval使python类实例在范围内全局？

Question

我有3个文件如下：

1）main.py：

from global_file import globalClass,evalCodeClass,execCodeClass
from sub_file import makeClassInstances
if __name__ == "__main__":
    globalClassInstance = makeClassInstances()
    print "In Main: globalClassInstance.name=",globalClassInstance.name
    print "In Main: globalClassInstance.classVar=",globalClassInstance.classVar
    print "In Main: globalClassInstance.classInstances['B']=",globalClassInstance.classInstances['B']
    globalClassInstance.classInstances['B'].run()

2）global_file.py：

global globalClassInstance
class globalClass():
    def __init__(self):
        self.classVar = None
        self.name = 'howdy'
        self.classInstances = {}

class evalCodeClass():
    def __init__(self,name=None):
        self.code = "globalClassInstance.classVar"
    def run(self,caller=None):
        exec self.code in globals()

class execCodeClass():
    def __init__(self,name=None):
        self.code = "globalClassInstance.classVar='hello'"
    def run(self,caller=None):
        exec self.code in globals()

3）sub_file.py:

from global_file import globalClass,evalCodeClass,execCodeClass

def makeClassInstances():
    globalClassInstance = globalClass()
    print globalClassInstance.name
    evalCodeInstance = evalCodeClass('A')
    execCodeInstance = execCodeClass('B')
    globalClassInstance.classInstances['A'] = evalCodeInstance
    globalClassInstance.classInstances['B'] = execCodeInstance
    return globalClassInstance

我希望能够使用exec和eval函数来设置实例globalClassInstance类变量classVar，但它似乎是{{1}当这些文件被分隔在这样的文件中时，找不到它们。

我得到以下内容：

globalClassInstance

当代码全部在一个文件中时，这可以正常工作。我在使用global关键字时尝试了很多变体，仍然无法在其他类实例中获取eval或exec代码以找出如何引用howdy In Main: globalClassInstance.name= howdy In Main: globalClassInstance.classVar= None In Main: globalClassInstance.classInstances['B']= <global_file.execCodeClass instance at 0x03131D00> Traceback (most recent call last): File "C:\Users\shinn\Documents\python\NLTK\StateMachine\New folder\main_file.py", line 9, in <module> globalClassInstance.classInstances['B'].run() File "C:\Users\shinn\Documents\python\NLTK\StateMachine\New folder\global_file.py", line 20, in run exec self.code in globals() File "<string>", line 1, in <module> NameError: name 'globalClassInstance' is not defined >>> 。

非常感谢您的帮助 - 我确定我只是个白痴; - ）