Problem of calling a decorated function in a dictionary

November 24, 2021

I have the following code:

collector_1 = {}

"""
The usage of spam() decorator is to append a function's name 
(the function being decorated by the spam() decorator) as a key
and the function itself (unexecuted) as the value to collector_1.
"""
def spam(collector):
    def decorator(function):
        collector.update({function.__name__: function})
        
        def wrapper():
            print("Wrapper is called.")
            return function()
        return wrapper
    return decorator

@spam(collector_1)
def egg():
    print("spam & egg is good.")

I then ran the egg function with this single line of code: egg(); and this is the result that I expected:

The wrapper is called.
spam & egg is good.

But when I ran it using the collector_1 dictionary:
collector_1["egg"]()

It only printed out one message:

spam & egg is good.

My task here is to call the function egg using the collector_1 dictionary, so I can import the collector_1 dictionary from different files to use it; is there any way to resolve this? Any help would be greatly appreciated!

>Solution :

You’re putting the original function in your collector, not the decorated version, which would be wrapper inside your spam function.

Try this instead:

def spam(collector):
    def decorator(function):
        def wrapper():
            print("Wrapper is called.")
            return function()
        collector[function.__name__] = wrapper
        return wrapper
    return decorator