在python3中引用全局变量时处理'NameError'，而不引发'SyntaxError' 处理名称错误会引发语法错误：

因此，我正在制作一个decorator函数，它将生成器函数与字典相关联，目的是使

send（）

函数使用起来不那么麻烦

默认行为是使用全局名称空间中定义的名为

global\u registry\u dict

的字典

如果

global\u registry\u dict

不存在，并且没有显式传入替代字典，则python会引发

namererror

当我试图通过在全局名称空间中创建变量来处理错误时，我得到一个

SyntaxError

告诉我在赋值之前引用了该变量。这是有道理的…但是…就像…这就是我想要解决的问题

任何帮助都将不胜感激

装饰师的来源： 整个模块的来源：

#全局注册表_dict={}
def使成为无状态参与者（func）：
"""
说明：
===========
此DECORATOR函数简化并集中了生成器上“send（）”的使用。
它通过将修饰函数关联到字典来实现这一点：
-默认情况下，将使用名为“global\u registry\u dict”的全局变量。
-默认情况下，如果global-NAMESPACE不存在，`global\u registry\u dict={}`将在该名称空间中创建。
重要提示：
==============
使用'registry_dict`kwarg手动将生成器func分配给备用字典：
`foo\u修饰的func（注册表dict=foo\u替代字典）`
要求：
============
您可以将“@make\u stateless\u actor”应用于以下任何生成器函数：
-在“=”符号的右侧包含一个“yield”表达式。
-包括`**kwargs`作为函数参数。
"""
def包装（注册表_dict=None，*args，**kwargs）：
尝试：
如果registry_dict为None:#在
else
子句中使用名称
global_registry_dict
。如果它是全局的，您必须在使用它之前声明它，就像错误消息所说的那样。通常，名称在函数的开头被声明为全局的。
我可以在开头添加一个检查，但我想我应该澄清一下：在使用
之后，除了发现它还不存在之外，是否没有其他方法实例化全局变量？是的。做你正在做的，除了将
全局
声明移到第一次使用名称上面，就像我刚才说的。Lol。是的。谢谢
def make_stateless_actor(func):
    def wrapper(registry_dict=None, *args, **kwargs):
        try:
            if registry_dict is None:
                internal_registry_dict = global_registry_dict
            elif isinstance(registry_dict, dict) or issubclass(registry_dict, dict):
                internal_registry_dict = registry_dict
            else:
                internal_registry_dict = global_registry_dict
        except NameError: # <<== CATCHES IF `global_registry_dict` IS REF'D BUT NOT DEFINED. 
            global global_registry_dict # <<== SYNTAX ERROR HAPPENS HERE
            global_registry_dict = {}
            internal_registry_dict = global_registry_dict
        gen = func(*args, **kwargs)
        next(gen)
        internal_registry_dict[func.__name__] = gen
    return wrapper

File "C:/yall/dont/need/to/know/this/generator_pipeline_utils.py", line 74
global global_registry_dict
^
SyntaxError: name 'global_registry_dict' is used prior to global declaration

# global_registry_dict = {}


def make_stateless_actor(func):
    """
    DESCRIPTION:
    ===========
    This DECORATOR FUNCTION simplifies & centralizes the use of `send()` on generators.

    It does this by ASSOCIATING the decorated function to a dictionary:

        - by default, a global variable named `global_registry_dict` will be used.
        - by default, `global_registry_dict = {}` will be created in the GLOBAL-NAMESPACE if it does not exist.

    IMPORTANT NOTE:
    ==============
    Use the `registry_dict` kwarg to manually assign your generator-func to an alternate dictionary:
            `foo_decorated_func(registry_dict=foo_alternative_dictionary)`

    REQUIREMENTS:
    ============
    You can apply `@make_stateless_actor` to any GENERATOR FUNCTION which:

        - INCLUDES A `yield` expression to the RIGHT of an `=` sign.
        - INCLUDES `**kwargs` as a function argument.
    """
    def wrapper(registry_dict=None, *args, **kwargs):
        try:
            if registry_dict is None: # <<-- necessary to prevent the next elif from throwing an exception.
                internal_registry_dict = global_registry_dict
            elif isinstance(registry_dict, dict) or issubclass(registry_dict, dict):
                internal_registry_dict = registry_dict
            else:
                internal_registry_dict = global_registry_dict
        except NameError:
            print('WARNING: global_registry_dict IS NOT DEFINED AND YOU DID NOT EXPLICITLY PASS registry_dict TO THE DECORATED FUNCTION.\n\
                  `global_registry_dict = {}` has been instantiated in the global-namespace.\n')
            global global_registry_dict
            global_registry_dict = {}
            internal_registry_dict = global_registry_dict
        gen = func(*args, **kwargs)
        next(gen)
        internal_registry_dict[func.__name__] = gen
    return wrapper

@make_stateless_actor
def printer(*args, **kwargs):
    while True:
        item = yield
        print("Got: ", item)

def send(name, msg, registry_dict=None):
    if registry_dict is None:
        global_registry_dict[name].send(msg)
    else:
        registry_dict[name].send(msg)

if __name__ == "__main__":
    printer(registry_dict=None) #<<==BEGIN THE CRAZY.
    # send('printer', 'HEY WHAT IS UP?')
    # send('printer', 666)
    # send('printer', [1, 'a', [], True])