Rapidinha #3 - programação declarativa com python

declarative.py

from collections.abc import MutableSequence
from itertools import islice
from functools import reduce


class List(MutableSequence):
    def __init__(self, seq):
        self._d = list(seq)

    def __delitem__(self, pos):
        del self._d[pos]

    def __getitem__(self, pos):
        return self._d[pos]

    def __setitem__(self, pos, val):
        self._d[pos] = val

    def __len__(self):
        return len(self._d)

    def insert(self, pos, val):
        self._d.insert(pos, val)

    def __repr__(self):
        return 'List({})'.format(self._d)

    def map(self, function):
        return List(map(function, self._d))

    def filter(self, function):
        return List(filter(function, self._d))

    def reduce(self, function):
        return reduce(function, self._d)

    def take(self, n):
        return List(islice(self._d, n))