Eratosthenes

gistfile1.py

def filterer(k, DEBUG = False):                                                                                
    def g():
        x = 1; m = yield;
        while True:
            m = yield (m if x<=k or x%k != 0 else 0)
            x += 1
    g = g()
    g.next()
    def _debug_filterer(x): 
        res =  map(g.send, x)
        print 'filterer({0})({1}) = {2}'.format(k, x, res)
        return res
    return _debug_filterer if DEBUG else lambda x: map(g.send, x)


ER = lambda N, DEBUG=False : filter(None, reduce(lambda s, f: f(s), (filterer(x, DEBUG) for x in range(2,1+N/2)), range(1,N+1)))


from itertools import *

def ifilterer(k, DEBUG = False):
    def g():
        x = 1; m = yield;
        while True:
            m = yield (m if x<=k or x%k != 0 else 0)
            x += 1
    g = g()
    g.next()
    def _debug_filterer(x): 
        res =  imap(g.send, x)
        print 'filterer({0})({1}) = {2}'.format(k, x, res)
        return res
    return _debug_filterer if DEBUG else lambda x: imap(g.send, x)


iER = lambda N, DEBUG=False: ifilter(None, reduce(lambda s, f: f(s), (ifilterer(x, DEBUG) for x in xrange(2,1+N/2)), xrange(1,N+1)))