from functools import reduce, partial

def identity(x):
    return x

def add3(a, b, c):
    print("adding {}, {}, and {}".format(a, b, c))
    return a + b + c

def compose2(f, g):
    # print("composing {} and {}".format(f, g))
    return lambda x: f(g(x))

def compose_list(fs):
    return reduce(compose2, fs, identity)

def partial_list(fs):
    return partial(*fs)


pipeline = [
    [ add3, 1, 2 ],
    [ add3, 3, 4 ],
    [ add3, 5, 6 ],
]


def main():
    pipe_partials = map(partial_list, reversed(pipeline))
    pipe_partials = list(pipe_partials)
    pipe_composed = compose_list(pipe_partials)

    v = pipe_composed(0)
    print(v)

if __name__ == "__main__":
    main()


# $ python3 evil_partials.py
# adding 1, 2, and 0
# adding 3, 4, and 3
# adding 5, 6, and 10
# 21