[Tutor] Generator next()

[Keith Winston]

I am beginning to think about decorators, generators, and the like. I'm
starting from zero. I've read a few PEPs, and looked at some code, and
maybe things are starting to sink in, though I don't really have enough
framework to hang it all on. It'll come. Anyway, I was trying to run some
timing code I swiped off the web, but ran into a problem with the .next()
function, which I THINK relates to the changes between how generators are
implemented between pre-3.3 and post, but I can't really tell. Here's the
code, stolen without apology from here:
http://enja.org/2011/03/09/a-python-function-timing-decorator/

import time

class Timing(object):
    def __init__(self):
        self.timings = {}
        self.col = self.__collector()
        self.col.next() #coroutine syntax

    def __collector(self):
        while True:
            (name, t) = (yield) #coroutine syntax
            if name in self.timings:
                self.timings[name]["timings"] += [t]
                self.timings[name]["count"] += 1
                self.timings[name]["total"] += t
            else:
                self.timings[name] = {} #if this entry doesn't exist yet
                self.timings[name]["timings"] = [t]
                self.timings[name]["count"] = 1
                self.timings[name]["total"] = t

    def __call__(self, func):
        """Turn the object into a decorator"""
        def wrapper(*arg, **kwargs):
            t1 = time.time() #start time
            res = func(*arg, **kwargs) #call the originating function
            t2 = time.time() #stop time
            t = (t2-t1)*1000.0 #time in milliseconds
            data = (func.__name__, t)
            self.col.send(data) #collect the data
            return res
        return wrapper

    def __str__(self):
        s = "Timings:\n"
        print(dir(self))
        for key in self.timings.keys():
            s += "%s | " % key
            ts = self.timings[key]["timings"]
            count = self.timings[key]["count"]
            total = self.timings[key]["total"]
            s += "average: %s | total: %s | count: %s\n" % (total / count,
total, count)
        return "%s" % s


if __name__ == "__main__":

    timings = Timing()

    @timings
    def add(x,y):
        for i in range(10000):
            c = x + y
        return c

    @timings
    def multiply(x,y):
        for i in range(10000):
            c = x * y
        return c

    for i in range(100):
        add(3.,4.)
        multiply(3., 4.)

    print(timings)



And here's the error message:

Traceback (most recent call last):
  File "/home/keithwins/Dropbox/Python/timer1.py", line 50, in <module>
    timings = Timing()
  File "/home/keithwins/Dropbox/Python/timer1.py", line 7, in __init__
    self.col.next() #coroutine syntax
AttributeError: 'generator' object has no attribute 'next'
-- 
Keith
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