Mailman 3 November 2000 - Python-Dev

site.py, .pth files and unix-dependencies
by Jack Jansen Nov. 19, 2000

Nov. 19, 2000

In the course of getting distutils to behave on the Mac I came across .pth files for the first time (all packages I ever tried until now used the __init__.py method of advertising themselves) and it turns out they don't work on the Mac. There's some funny code in site.py that triggers on "os.sep == '/'". I've added an "elif os.sep == ':'" for the mac-specific location where site-python is (sys.prefix + :lib:site-python), but checking for os.sep in stead of simply checking that sys.platform==… [View More]

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socket.error should be an IOError?
by Ka-Ping Yee Nov. 18, 2000

Nov. 18, 2000

In socketmodule, socket.error is currently just a plain old error (derived only from Exception). Looks to me like it should be an IOError. Do you agree? line 2379 of socketmodule.c: ��d = PyModule_GetDict(m); ��PySocket_Error = PyErr_NewException("socket.error", NULL, NULL); ��if (PySocket_Error == NULL) ...just change that first NULL to PyExc_IOError. -- ?!ng "All models are wrong; some models are useful." -- George Box

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Starship, Python.org, etc.
by M.-A. Lemburg Nov. 18, 2000

Nov. 18, 2000

Hi, sorry to bother you again with this, but the current state of Python's community elements is in such a bad shape, that I'm getting more and more frustrated... First, starship is taken off the net due to a mailing problem. After a few days starship resurfaces: but apparently using some really old backup which didn't even contain all files -- at least the .ssh dirs seem to be lost causing RSA logins using SSH to fail (don't know about normal logins -- my old passwords don't work anymore … [View More]

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imputil
by Thomas Heller Nov. 17, 2000

Nov. 17, 2000

imputil, which is now an official part of python, changes the semantics of sys.path as soon as importers are installed. On the other hand, a quick and dirty search finds at least these files in the standard library where it is assumed that sys.path is a list of strings: linecache.py, profile.py, pdb.py, pyclbr.py Should imputil be fixed to install the ImportManager in a different way (not installing the importers into sys.path), or should the library be fixed? Thomas

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forwarded message from nimoy
by Fred L. Drake, Jr. Nov. 17, 2000

Nov. 17, 2000

It sounds like people are happy with Python. ;) Just thought I'd pass this bit of praise araound, since it seems to apply to everyone's efforts. -Fred -- Fred L. Drake, Jr. <fdrake at acm.org> PythonLabs at Digital Creations

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PEP-228 (fw)
by Moshe Zadka Nov. 17, 2000

Nov. 17, 2000

I'm forwarding this message about PEP-228, but I haven't fully understood it. In any case, since PEP-228 is apparently not a 2.1 candidate, I've told Michael that his remarks will be considered, but they are not relevant yet. ------- Forwarded Message From: Michael McLay <mclay(a)nist.gov> Date: Fri, 17 Nov 2000 04:20:45 -0500 (EST) To: pep(a)zadka.site.co.il Subject: PEP:228 I've dropped off the Python mailing lists for the last couple years because the volume is too high and I don't … [View More]have time to contribute to the discussion. I do read the summaries and PEP:228 was mentioned in reference to the 2.1 release. I'd like to see this problem solve in the 2.1 release and I have a few thoughts on the matter that may be of use to this task. Is there a mailing list specific to PEP:228 or would I have to join python-dev to participate in the discussion? Please feel free to forward my message to the python-dev list or use my comments in PEP:228. Python's use in the XML community is growing and broad-based XML support in Python may be key to widespread adoption of Python. There is some support for XML Schema, the XML Schema Validation software is written in Python, but there is no direct support in the core Python XML library. One problem area for an XML Schema implementation is related to the numerical types in Python. The ability to implement XML Schema types could be improved if the requirements are considered when creating the PEP:228 implementation. And from the Python language perspective a review of the numerical model used in XML Schema may be useful to the discussion of the revised numerical model for Python. The authors of the XML Schema specification put a good deal of effort into defining a modern, portable numerical model and I think it might be a good fit with the Python object model. I might also be possible that the XML Schema type and entity definition mechanism would be helpful in the discussion of defining type interfaces for Python. A table of simple types built into XML Schema are defined in: http://www.w3.org/TR/xmlschema-0/#simpleTypesTable These are defined more fully in "XML Schema Part 2: DataTypes" at: http://www.w3.org/TR/2000/CR-xmlschema-2-20001024/ This includes a discussion of the difference between built-inprimitive and built-inderived datatypes. The derived types are defined in the XML Schema at: http://www.w3.org/2000/10/datatypes.xsd In this document, for instance, an integer is derived from a decimal type in XML Schema. <simpleType name="integer"> <restriction base="decimal"> <scale value="0" fixed="true"/> </restriction> </simpleType> The use of XML Schema in conjunction with Python would be very helpful to a soon to be large domain of applications. I am working with a group that is currently defining 20 standards using XML Schema and this is probably just the tip of the iceburg. I need to be able to define constrained numerical types as defined in XML Schma. In Python this might look like: size = ConstrainedDecimal(initial=2, minInclusive=2, maxInclusive=3000, scale=0) for i in range(3000-2): size += 1 print size The ConstrainedDecimal would define a restriction range on the value of "size". ------- End of Forwarded Message -- Moshe Zadka <sig(a)zadka.site.co.il> This is a signature anti-virus. Please stop the spread of signature viruses! [View Less]

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coroutines and microthreads
by Guido van Rossum Nov. 17, 2000

Nov. 17, 2000

(I would cc this to the Stackless list as well, except that starship mail is still down it seems. I *am* posting to the python-coro list, which seems to be appropriate here. Will Ware, are you listening?) Coroutines! ----------- Inspired by Gordon McMillan's Stackless tutorial (http://www.mcmillan-inc.com/stackless.html), I've been thinking more about a coroutine API for Python. I proposed one before (see the thread "uthread strawman" in python-dev). I've been thinking a bit more and am … [View More]now revising my proposal a bit. I'll first give an example. Tim Peters gave a standard example to return the fringe of a list (checked in as Demo/threads/fcmp.py). Using my proposed API this example could be rewritten a bit cleaner, as follows: from coro import coroutine, suspend, EarlyExit # Provisional module name def fringe(L): for x in L: if type(x) is type(L): fringe(x) else: suspend(x) def printinorder(L): c = coroutine(f, L) try: while 1: print c(), except EarlyExit: pass print x = [0, 1, [2, [3]], [4,5], [[[6]]]] printinorder(x) # prints "0 1 2 3 4 5 6" This is about as simple as it gets. It supports both generators (like the example here) and coroutines (like Tim's Demo/threads/squasher.py example). Besides the APIs shown here (coroutine(), suspend(), and EarlyExit) I propose a function current() which returns the current coroutine object. There should also be a way to kill a coroutine (or at least to send an exception). When a coroutine falls through at its end, *some* other coroutine needs to be resumed. I believe this can be implemented with a much simplified stackless approach, that doesn't cater towards continuations (but still borrows a lot of wisdom from Christian's Stackless). It can also be implemented using threads, which should give some hope for getting the same API supported in JPython, making it more attractive. I am hoping to create an implementation on top of Stackless, just to experiment with the idiom. Microthreads? ------------- I'm much less clear about microthreads (uthreads). Last time, I thought this was a fancy name for coroutines. It isn't! Microthreads are "almost real" threads, with round-robin scheduling. What makes them attractive to some is the fact that they don't use operating system resources: there's no OS-level stack or kernel process table entry associated with them. This also accounts for their biggest weakness: when a microthread is suspended for I/O, *all* microthreads are suspended. In limited contexts, such as a network server, this can be solved by an approach similar to that in Gordon's SelectDispatcher. (It would be a titanic effort to do this for every potentially blocking I/O operation, and it probably wouldn't work well with C extensions.) I'm not sure what applications require the round-robin scheduling property of uthreads -- certainly Gordon's application would seem to be doing just fine without it (I'm not sure if it is being scheduled round-robin or not). Proper round-robin scheduling for uthreads requires explicit switching code in the Python interpreter. Stackless provides this, at the same place where in regular Python the global interpreter lock is released and re-acquired to give other threads a chance to run. Is this needed? --Guido van Rossum (home page: http://www.python.org/~guido/) [View Less]

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screwup on the patches & bugs notifications
by Jeremy Hylton Nov. 17, 2000

Nov. 17, 2000

I hurried to get notifications of outstanding patches and bugs last night and botched both of them. Sorry about that. If you can a message about patches, you can disregard it entirely. It was made from an old snapshot of the SF database. The bug mail contains current bugs, but the formatting of the mail headers was off. I've fixed that for the future. Jeremy

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Python/Distutil draft PEP
by A.M. Kuchling Nov. 17, 2000

Nov. 17, 2000

PEP: XXX Title: Using Distutils to Build Python Version: $Revision: $ Author: akuchlin(a)mems-exchange.org (A.M. Kuchling) Status: Draft Type: Standards Created: 16-Nov-2000 Introduction The Modules/Setup mechanism has some flaws: * People have to remember to uncomment bits of Modules/Setup in order to get all the possible modules. * Moving Setup to a new version of Python is tedious; new modules have been added, so you can't just copy the older version, but … [View More]

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curses demos
by Andrew Kuchling Nov. 16, 2000

Nov. 16, 2000

I'd like to add a Demo/curses directory to the CVS tree. If anyone has reasonably small programs that use the curses module, please let me know. Right now I have two programs: a Life game that I wrote, and Alexei Gilchrist's cfm (http://cfm.sourceforge.net/), which is a little file manager. I also want to write scripts to demonstrate reading the mouse, and writing a threaded curses program. --amk

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