Mailman 3 July 1999 - Python-Dev

RE: [Python-Dev] RE: NT select.select?
by Brian Lloyd July 30, 1999

July 30, 1999

Guido wrote: > > Brian, > > (Also in response to your bug report.) I'm a little worried that > upping the limit to 1024 would cause some performance problems if > you're making a lot of select() calls. The select allocates three > arrays of length FD_SETSIZE+3; each array item is 12 bytes. This is a > total allocation of more than 36K for a meager select() call! > And all > that memory also has to be cleared by the FD_ZERO() call. > > If you actually … [View More]

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RE: NT select.select?
by Brian Lloyd July 30, 1999

July 30, 1999

> Is there some low limit on maximum number of sockets you can > have in the > Python-NT's select call? A program that happens to work > perfectly on Linux > seems to die on NT around 64(?) sockets to the 'too many file > descriptors > in call' error. > > Any portable ways to bypass it? > > -Markus Hi Markus, It turns out that NT has a default 64 fd limit on arguments to select(). The good news is that you can actually bump the limit up to whatever … [View More]

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Re: [Python-Dev] End of the line
by Jack Jansen July 28, 1999

July 28, 1999

> [Jack seems to like an asynch IO model] > > > def foo(): > > obj = stdin.delayed_read() > > obj2 = stdout.delayed_write("data") > > do_lengthy_computation() > > data = obj.get() # Here we wait for the read to complete > > del obj2 # Here we wait for the write to > > complete. > > > > This gives a fairly nice programming model. > > Indeed. Taking this a little further, I come up with something like: > > inlock … [View More]

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Tcl news
by David Ascher July 28, 1999

July 28, 1999

8.2b1 is released: Some surprising news: they now use cygwin tools to do the windows build. Not surprising news: they still haven't incorporated some bug fixes I submitted eons ago =) http://www.scriptics.com/software/relnotes/tcl8.2b1 --david

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Re: [Python-Dev] End of the line
by Jack Jansen July 27, 1999

July 27, 1999

> What Im getting at is that a Python IO model should maybe go a little > further than "tradtional" IO - asynchronous IO and synchronisation > capabilities should also be specified. Of course, these would be optional, > but it would be excellent if a platform could easily slot into pre-defined > Python semantics if possible. What Python could do with reasonable ease is a sort of "promise" model, where an I/O operation returns an object that waits for the I/O to complete upon … [View More]

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continuations for the curious
by Christian Tismer July 27, 1999

July 27, 1999

Howdy, my modules are nearly ready. I will be out of my office for two weeks, but had no time to finalize and publish yet. Stackless Python has reached what I wanted it to reach: A continuation can be saved at every opcode. The continuationmodule has been shrunk heavily. Some extension is still needed, continuations are still frames, but they can be picked like Sam wanted it originally. Sam, I'm pretty sure this is more than enough for coroutines. Just have a look at getpcc(), this is now … [View More]

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I'd like list.pop to accept an optional second argument giving a default value
by Jim Fulton July 27, 1999

July 27, 1999

I like the list pop method because it provides a way to use lists as thread safe queues and stacks (since append and pop are protected by the global interpreter lock). With pop, you can essentially test whether the list is empty and get a value if it isn't in one atomic operation: try: foo=queue.pop(0) except IndexError: ... empty queue case else: ... non-empty case, do something with foo Unfortunately, this incurs exception overhead. I'd rather do something like: … [View More]

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RE: [Python-Dev] End of the line
by Brian Lloyd July 26, 1999

July 26, 1999

> [Tim, notes that Perl line-at-a-time text mode input runs 3x > faster than > Python's on his platform] > > And much to my surprise, it turns out Perl reads lines a > character at a time > too! And they do not reimplement stdio. But they do cheat. > > [some notes on the cheating and PerlIO api snipped] > > The usual *implementation* of these guys is as straight macro > substitution > to the corresponding C stdio call. It's possible to > … [View More]

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continuationmodule.c preview
by Christian Tismer July 25, 1999

July 25, 1999

Howdy, please find attached my latest running version of continuationmodule.c which is really able to do continuations. You need stackless Python 0.3 for it, which I just submitted. This module is by no means ready. The central functions are getpcc() and putcc. Call/cc is at the moment to be done like: def callcc(fun, *args, **kw): cont = getpcc() return apply(fun, (cont,)+args, kw) getpcc(level=1) gets a parent's current continuation. putcc(cont, val) throws a continuation. At … [View More]

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Importing extension modules
by M.-A. Lemburg July 22, 1999

July 22, 1999

I'm currently testing a pure Python version of mxDateTime (my date/time package), which uses a contributed Python version of the C extension. Now, to avoid problems with pickled DateTime objects (they include the complete module name), I would like to name *both* the Python and the C extension version mxDateTime. With the current lookup scheme (shared mods are searched before Python modules) this is no problem since the shared mod is found before the Python version and used instead, so getting … [View More]

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