decfunc 1.0.0

decfunc

Creating decorators with arguments made easy.

Creating decorators in Python is easy, unless you want to use arguments. The aim of this library to abstract away some code that makes argument-ed decorators work.

Documentation

This library only contains one class: wrapper. The mutate method of this class is responsible for your business logic. You can simply use a class inheriting from wrapper as the decorator. For example:

from decfunc import wrapper


class square_root(wrapper):
    def mutate(self, wrapped, *args, **kwargs):
        return wrapped(*args, **kwargs) ** (1 / 2)


@square_root
def get_number(*args, **kwargs):
    return 4


get_number()  # 2.0

In this example, decorated function's return value is mutated so that its square root is returned instead. As you can see mutate method takes a wrapped, which is the decorated class or function, and *args, **kwargs, which correspond to given args and kwargs of the decorated function/class (you may also use the signature of the decorated callable).

Now lets change this a bit so that we can give pass an argument named n, which will denote to nth root, instead of square root.

from decfunc import wrapper


class nth_root(wrapper):
    def __init__(self, n=2):
        self.n = n

    def mutate(self, wrapped, *args, **kwargs):
        return wrapped(*args, **kwargs) ** (1 / self.n)


@nth_root(n=3)
def get_number(*args, **kwargs):
    return 27


@nth_root
def get_another_number(*args, **kwargs):
    return 16


get_number()  # 3.0
get_another_number()  # 4.0

As you can see, in order to add arguments to the decorator you can use __init__, whose signature will be the signature of the decorator.