Decorators

[yksingh1097]

I was going through a tutorial and encountered this code. Can anybody please make me understand the control flow of this code? Like which line is executed first and what is being passed as argument. I apologize if it is silly but i am mid newbie.

I know that when control encounters @decorator_function, it treat it as the beneath function being passed as argument to the decorator function but then it means that

original_function=display

or

original_function=display(): print('display function ran') 

or what else.
And also when wrapper function is returned, than does that mean or can we say that display defination is replaced by wrapper function

@decorator_function
def display():
    wrapper_function

OR

@decorator_function
wrapper_function

Please explain...

def decorator_function(original_function):
    def wrapper_function():
        print('wrapper executed this before {}'.format(original_function.__name__))
        return original_function()
    return wrapper_function

@decorator_function
def display():
    print('display function ran')

#display()

if __name__ == '__main__':
    display()

Output:
wrapper executed this before display
display function ran

I understand that the above python code and the below code both are same. But need to understand the proper control flow.

def decorator_function(original_function):
    def wrapper_function():
        print('wrapper executed this before {}'.format(original_function.__name__))
        return original_function()
    return wrapper_function

#@decorator_function
def display():
    print('display function ran')

#display()

if __name__ == '__main__':
    display()
    dd=decorator_function(display)
    dd()

[Gribouillis]

The only thing to understand is that

@spam
def eggs():
    print('ham')

is equivalent to

def eggs():
    print('ham')
eggs = spam(eggs)

[yksingh1097]

The only thing to understand is that

@spam
def eggs():
    print('ham')

is equivalent to

def eggs():
    print('ham')
eggs = spam(eggs)

Okay thanks Sir. I get it .