Chain functions together by defining the order of operations that are performed on an object. Can allow users to dynamically create functions.

function_chaining.py

from functools import partial


def add(x, y):
    return x + y


def mul(x, y):
    return x * y


def chain(obj, funcs, callback=None):
    func = funcs[-1]
    if callback:
        callback(funcs)
    if len(funcs) == 1:
        return func(obj)

    return func(chain(obj, funcs[:-1], callback=callback))


ops = [
    partial(add, 2),
    partial(mul, 3),
    partial(add, -1),
]


x_plus_2_times_three_minus_1 = partial(
    chain,
    funcs=[
        partial(add, 2),
        partial(mul, 3),
        partial(add, -1),
    ],
)

print(chain(5, ops, callback=lambda xx: print("on function: ", xx[-1])))
"""
>>> on function:  functools.partial(<function add at 0x7f2ab0d4cea0>, -1)
>>> on function:  functools.partial(<function mul at 0x7f2ab0d4ce18>, 3)
>>> on function:  functools.partial(<function add at 0x7f2ab0d4cea0>, 2)
>>> 20
"""

print(x_plus_2_times_three_minus_1(5))
"""
>>> 20
"""