为Python函数参数提供额外装饰/元数据的好方法是什么?

decorator是向函数添加元数据的好方法。添加一个将类型列表附加到.params属性或其他内容的类型:

def takes(*args):
    def _takes(fcn):
        fcn.params = args
        return fcn
    return _takes

@takes("time", "temp", "time")
def do_stuff(start_time, average_temp, stop_time):
    pass

我会用一些装饰物:

class TypeProtector(object):
    def __init__(self, fun, types):
        self.fun, self.types = fun, types
    def __call__(self, *args, **kwargs)
        # validate args with self.types
        pass
        # run function
        return fun(*args, **kwargs)

def types(*args):
    def decorator(fun):
        # validate args count with fun parameters count
        pass
        # return covered function
        return TypeProtector(fun, args)
    return decorator

@types(Time, Temperature)
def myfunction(foo, bar):
    pass

myfunction('21:21', '32C')
print myfunction.types

“蟒蛇式”的方法是 function annotations .

def DoSomething(critical_temp: "temperature", time: "time")
    pass

对于python2.x,我喜欢使用docstring

def my_func(txt):
    """{
    "name": "Justin",
    "age"   :15
    }"""
    pass

并且它可以通过这个代码段自动分配给函数对象

for f in globals():
    if not hasattr(globals()[f], '__call__'):
        continue
    try:
        meta = json.loads(globals()[f].__doc__)
    except:
        continue
    for k, v in meta.items():
        setattr(globals()[f], k, v)