Function-based decorators

example.py

def add2(func):
    def wrapper(*args, **kwargs):
        return func(*args, **kwargs) + 2
    return wrapper


@add2
def foo(number):
    return number * 2


f = foo(5)
print(f)


def add5(func):
    def wrapper(*args, **kwargs):
        return func(*args, **kwargs) + 5
    return wrapper


def bar(number):
    return number ** 2


# Can also be defined without decorator function.
bar = add5(bar)
f = bar(2)
print(f)


# What if I want to increment by 8 must I create a new function add8? No.
# And it is not a decorator this is a function which going to return a decorator function.
def add(number):
    def decorator(func):
        def wrapper(*args, **kwargs):
            return func(*args, *kwargs) + number
        return wrapper
    return decorator


def multiply(number):
    def decorator(func):
        def wrapper(*args, **kwargs):
            return func(*args, *kwargs) * number
        return wrapper
    return decorator


@multiply(3)
@add(8)
def baz(number):
    return number


f = baz(8)
print(f)


# There is an another way to calling the function
def qux(number):
    return number ** 3


qux = add(8)(qux)
print(qux(3))


# This kind of functions can be used in a method. But it has to changed with this way
# Give your attention to function call in wrapper.
def add(number):
    def decorator(func):
        def wrapper(self, *args, **kwargs):
            return func(self, *args, **kwargs) + number
        return wrapper
    return decorator


class Foo:
    def __init__(self, number):
        self.number = number

    @add(2)
    def bar(self):
        return self.number ** 2


f = Foo(8)
print(f.bar())