import functools
    import re
    import sys

    URL_RE = re.compile(r"href=(?P<quote>[\"'])(?P<url>[^\1]+?)(?P=quote)", re.IGNORECASE)
    flags = re.MULTILINE|re.IGNORECASE|re.DOTALL
    H1_RE = re.compile(r"<h1>(?P<h1>.+?)</h1>", flags)
    H2_RE = re.compile(r"<h2>(?P<h2>.+?)</h2>", flags)

    def coroutine(function):
        @functools.wraps(function)
        def wrapper(*args, **kargs):
            generator = function(*args, **kargs)
            next(generator)
            return generator

        return wrapper
    @coroutine
    def reporter():
        ignore = frozenset({"style.css", "index.html", "favicon.png"})
        while True:
            print("reporter before")
            match = (yield)
            print("reporter after")
            if match is not None:
                groups = match.groupdict()
            if "url" in groups and groups['url'] not in ignore:
                print(" URL: ", groups['url'])
            elif "h1" in groups:
                print(" H1: ", groups['h1'])
            elif "h2" in groups:
                print(" H2: ", groups['h2'])

    @coroutine
    def regex_matcher(reveiver, regex):
        while True:
            print("regex before")
            text = (yield)
            print("regex after")
            for match in regex.finditer(text):
                receiver.send(match)

    receiver = reporter()
    matchers = (regex_matcher(receiver, URL_RE),
        regex_matcher(receiver, H1_RE),
        regex_matcher(receiver, H2_RE))

    try:
        for file in sys.argv[1:]:
            print(file)
            html = open(file, encoding="utf-8").read()
            for matcher in matchers:
                matcher.send(html)
    finally:
        for matcher in matchers:
            matcher.close()
        receiver.close()

迭代器

带yield的函数，就是一个迭代器

    import sys
    def iters():
        while True:
            test = (yield)
            if test == "a":
                print("received a")
            elif test == "b":
                print("received b")
            else:
                print("others [" + str(test) + "] received")

    args = sys.argv
    sender_text = args[1] if len(args) > 1 else None

    it = iters()
    it.send(None)    #这样，开始一个迭代器时，都必须先调用it.send(None)，或者next(it)，使迭代器走到yield那行代码，更好的办法，可以使用方法修饰器，见下
    # next(it)

    for i in range(10):
        it.send(sender_text + str(i))
        next(it)

启动一个迭代器，要么执行next(iterator)， 要么iterator.send(None)，这时，迭代器会自动走到yield这行，等待，当执行下一次next或者收到send(str)时，继续从这一行往下走
next其实就是send(None)

@方法修饰器

    def next_iterator(function):
        @functools.wraps(function)
        def wrapper(*args, **kargs):
            func = function(*args, **kargs)
            next(func)  #func.send(None)
            return func

        return wrapper

    @next_iterator
    def iters():
        ......  #代码见上