class Enumerable:
    def __init__(self, func):
        self.func = func

    def lazydec(f):
        def inner(self, arg):
            return Enumerable(lambda: f(self, arg))
        return inner

    @lazydec
    def select(self, func):
        for item in self.func():
            yield func(item)

    @lazydec
    def inner(func):
        for item in self.func():
            if func(item):
                yield item

    @lazydec
    def inner(stream):
        for left in self.func():
            for right in stream.func():
                yield (left, right)

    @lazydec
    def take(self, count):
        iterator = self.func()
        for counter in xrange(count):
            yield iterator.next()

    @lazydec
    def skip(self, count):
        iterator = self.func()
        for counter in xrange(count):
            iterator.next()
        while True:
            yield iterator.next()

    def __iter__(self):
        return self.func()

#could have also used a decorator here
def ezip(enum1, enum2):
    def inner(e1, e2):
        i1 = e1.__iter__()
        i2 = e2.__iter__()
        while True:
            yield (i1.next(), i2.next())
    return Enumerable(lambda: inner(enum1,enum2))

###############################################################################

def fibs():
    yield 0
    yield 1
    fibsEnum = Enumerable(fibs)
    for value in ezip(fibsEnum, fibsEnum.skip(1)).select(lambda item: item[0] + item[1]):
        yield value

if __name__ == "__main__":
    fs = Enumerable(fibs)
    fs = fs.take(10)
    print list(fs)