Alex Martelli wrote: > Lawrence D'Oliveiro <[EMAIL PROTECTED]> wrote: > > >>In article <[EMAIL PROTECTED]>, >> Kirk McDonald <[EMAIL PROTECTED]> wrote: >> >> >>>I want to somehow, in some way, provide an iteration interface to this >>>function. Thoughts? >> >>Run it in a separate thread/process? > > > Sounds best to me. Specifically, given (e.g.) something like the OP's > > def func(callback): > for i in [1, 2, 3, 4, 5]: > callback(i) > > we might have a wrapper such as: > > import thread > import Queue > > def wrap_cb_into_gen(func): > q = Queue.Queue(1) # maximum size of 1 > def callback(item): > q.put(item) > all_done_sentinel = object() > def thread_skeleton(): > func(callback) > q.put(all_done_sentinel) > thread.start_new_thread(thread_skeleton, ()) > while True: > item = q.get() > if item is all_done_sentinel: break > yield item > > > Of course, there are lighter-weight options than a length-1 Queue for > the purpose of synchronizing these two threads, but I always tend to > prefer Queue (for its simplicity, generality, solidity) to other > synchronization structures and architectures, unless there is some very > strong reason to do otherwise in a specific case. Also, I normally use > module threading rather than the lower-level module thread -- here, > clearly, either one will do just fine. > > > Alex
Threads are probably a weak point of mine. I have little experience with them, and so I am inclined to paranoia while using them. What implications does this have for "func"? In my case, it is a function in an extension module. Does it have to be thread safe? If it isn't, what limitations does this impose on the use of this wrapper? All that aside, I read the previous threads but it took until just now to understand how this works. :-) I'll probably have a go at implementing this in D, as that will be more convenient for the library... -Kirk McDonald -- http://mail.python.org/mailman/listinfo/python-list
