fredgj / mom

The mother of all decorators

Mom

Mom is a python module that contains one single decorator called decorate_with, but this is also a powerful decorator. It's the mother of all decorators.

In the future I might add some more meta stuff here, but at the moment I only need this single decorator.

It might not be the most useful decorator, but it intends to solve a problem, at least for some people.

Usage

decorate_with is a decorator that takes other decorators as input, including their arguments and/or keyword arguments (if any), in order to apply them to a function.

Some people think decorating their functions with several decorators like in the example below looks way too ugly.

@decorator1
@decorator2
@decoraror3(arg1, arg2)
def func(*args, **kwargs):
    pass

decorate_with lets you decorate your functions with all the decorators you need in one single "decoration".

from mom import decorate_with

@decorate_with(decorator1, decorator2, [decorator3, arg1, arg2])
def func(*args, **kwargs):
    pass

# you can also add each decorator to a list if that's what you prefer,
# like this:
@decorate_with([decorator1],[decorator2], [decorator3, arg1, arg2])
def func(*args, **kwargs):
    pass

As you can see in the example above, decorate_with takes other decorators as arguments and applies them to the function. If the decorator has no arguments you can just pass it in directly, or as a list, it's up to the user. Though, passing them in directly looks slightly more elegant. If the decorator has any arguments you need to add it to a list together its arguments.

If a decorator has been defined with default arguments you need to pass the keyword arguments dictionary to decorate_with, in case you have any keyword arguemnts to pass.

First, lets write a simple decorator with two default arguments. In the reality there are three default arguments, but func will be overwritten by wrapper's scope inside the else part if msg1 and/or msg2 have a value.

def decorator(func=None, msg1=None, msg2=None):
    if func:
        def wrapper(*args, **kwargs):
            return func(*args, **kwargs)
        return wrapper
    else:
        def wrapper(func):
            def func_wrapper(*args, **kwargs):
                if msg1:
                    print(msg1)
                if msg2:
                    print(msg2)
                return func(*args, **kwargs)
            return func_wrapper
        return wrapper

Now we can apply it like this:

@decorate_with([decorator, {'msg1':'hello', 'msg2':'world'}])
def func(*args, **kwargs):
    pass

Or without any arguments

@decorate_with(decorator)
def func(*args, **kwargs):
    pass