Question

First I’ve learned what Python decorators are and how they work. And I’d like it to do something like this:

def age_over_18(go_enjoy_yourself):

    def go_home_and_rethink_your_life():

        return 'So you should go home and rethink your life.'

    return go_enjoy_yourself if age_stored_somewhere > 18 else go_home_and_rethink_your_life

@age_over_18
def some_porn_things():

    return '-Beep-'

But I found out that decorators are executed when the function is first read by Python, that means this function will actually do nothing.

I know I can write something like:

def some_porn_things():

    if age_stored_somewhere > 18:
        ...
    else:
        ...

But I just think decorators are graceful and easy to understand, so the question is:

Can I delay a decorator to happen until I call the function?

Answer 1

The trick is just to ensure that the check happens in your inner function, not the outer one. In your case:

def age_over_18(go_enjoy_yourself):
    def are_you_over_18():
        if age > 18:
            return go_enjoy_yourself()
        else:
            return 'So you should go home and rethink your life.'

    return are_you_over_18