fiber(cooperative multi-threading)

[iccananea at gmail.com]

Hi!

Since your interest in fibers/coroutines is related to writing
simulators, you should try the SimPy package (simpy.sf.net), which is
a process-based discrete event simulator that uses generators as
processes.

On 22 dez, 09:10, Akihiro KAYAMA <kay... at st.rim.or.jp> wrote:
> Hi all.
>
> I found cooperative multi-threading(only one thread runs at once,
> explicit thread switching) is useful for writing some simulators.
> With it, I'm able to be free from annoying mutual exclusion, and make
> results deterministic.
>
> For this purpose, and inspired by Ruby(1.9) fiber, I wrote my own
> version of fiber in Python.
>
> It just works, but using native Python threads for non-preemptive
> threading is not cost-effective. Python has generator instead but it
> seemed to be very restricted for general scripting. I wish I could
> write nested (generator) functions easily at least.
>
> Is there any plan of implementing real (lightweight) fiber in Python?
>
> ------------------------------------------------------------
> import threading
>
> class Fiber(threading.Thread):
>     def __init__(self):
>         threading.Thread.__init__(self)
>
>         self.semaphore_running = threading.Semaphore(0)
>         self.semaphore_finish = None
>         self.val = None
>
>         self.setDaemon(True)
>         self.start()
>         self.start = self.start_fiber
>
>     def start_fiber(self):
>         self.semaphore_finish = threading.Semaphore(0)
>         self.semaphore_running.release()
>         self.semaphore_finish.acquire()
>
>     def run(self):              # override
>         self.semaphore_running.acquire()
>         self.main()
>         if self.semaphore_finish is not None:
>             self.semaphore_finish.release()
>
>     def switchto(self, fiber, val=None):
>         fiber.val = val
>         fiber.semaphore_running.release()
>         self.semaphore_running.acquire()
>         return self.val
>
>     def main(self):             # should be overridden
>         pass
>
> class F1(Fiber):
>     def main(self):
>         print "f1 start"
>         self.switchto(f2)
>         print "f1 foo"
>         v = self.switchto(f2)
>         print "f1 v=%s world" % v
>         self.switchto(f2, "OK")
>         print "f1 end"
>
> class F2(Fiber):
>     def main(self):
>         print "f2 start"
>         self.switchto(f1)
>         print "f2 bar"
>         result = self.switchto(f1, "Hello, ")
>         print "f2 result=%s" % result
>         print "f2 end"
>         self.switchto(f1)
>
> f1 = F1()
> f2 = F2()
>
> print "start"
> f1.start()
> print "end"
>
> -- kayama