functional programming in python with Pipe

class Pipe(object):
    def __init__(self, func):
        self.func = func
 
    def __ror__(self, other):
        def generator():
            for obj in other:
                if obj is not None:
                    yield self.func(obj)
        return generator()
 
@Pipe
def even_filter(num):
    return num if num % 2 == 0 else None
 
@Pipe
def multiply_by_three(num):
    return num*3
 
@Pipe
def convert_to_string(num):
    return 'The Number: %s' % num
 
@Pipe
def echo(item):
    print item
    return item
 
def force(sqs):
    print sqs
    for item in sqs: print item
 
nums = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
 
force(nums | even_filter | multiply_by_three | convert_to_string | echo)






from pipe import *




def i(k):
    guess=1
    yield guess
    while abs(guess*guess-k)<.001:
        guess=(guess+k/guess)/2.
        yield guess
    return
for z in i(4):
    print z,



def improve(guess, x):
    return (guess+x/guess)/2.

K = 2 
print reduce(lambda guess, _: improve(guess, K), range(4), 1)


# reduce(lambda guess, _: improve(guess, K), range(10), 1) | take_while(lambda guess: abs(guess*guess-K)<.001)


# linear recursive
def lsum(f, a, b):
    if (a>b):
        return 0
    else:
        return f(a)+ lsum(f, a+1, b)

print lsum(lambda x:x, 1, 5)

# tail recursive
def tsum(f, a, b):
    def loop(a, acc):
        if a>b:
            return acc
        else:
            return loop(a+1, acc + f(a))
    return loop(a,0)

print tsum(lambda x:x, 1, 5)