Mailman 3 May 2007 - Python-Dev

Summary of Tracker Issues
by Tracker 26 May '07

26 May '07

ACTIVITY SUMMARY (05/20/07 - 05/27/07) Tracker at http://bugs.python.org/ To view or respond to any of the issues listed below, click on the issue number. Do NOT respond to this message. 1649 open ( +0) / 8584 closed ( +0) / 10233 total ( +0) Average duration of open issues: 806 days. Median duration of open issues: 757 days. Open Issues Breakdown open 1649 ( +0) pending 0 ( +0)

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The docs, reloaded
by Georg Brandl 26 May '07

26 May '07

Hi, over the last few weeks I've hacked on a new approach to Python's documentation. As Python already has an excellent documentation framework, the docutils, with a readable yet extendable markup format, reST, I thought that it should be possible to use those instead of the current LaTeX->latex2html toolchain. For the impatient: the result can be seen at <http://pydoc.gbrandl.de>. I've written a converter tool that handles most of the LaTeX markup and turns it into reST, as well as a builder tool that adds many custom directives and roles, and also features like index generation and cross-document linking. (What you can see at the URL is a completely statical version of the docs, as it would be shipped with the distribution. For the real online docs, I have more plans; I'll come to that later.) So why the effort? Here's a partial list of things that have already been improved: - the source is much more readable (for examples, try the "view source" links in the left navbar) - all function/class/module names are properly cross-referenced - the HTML pages are generated from templates, using a language similar to Django's template language - Python and C code snippets are syntax highlighted - for the offline version, there's a JavaScript enabled search function - the index is generated over all the documentation, making it easier to find stuff you need - the toolchain is pure Python, therefore can easily be shipped What more? If there is support for this approach, I have plans for things that can be added to the online version: - a "quick-dispatch" function: e.g., docs.python.org/q?os.path.split would redirect you to the matching location. - "interactive patching": provide an "propose edit" link, leading to a Wiki-like page where you can edit the source. From the result, a diff is generated, which can be accepted, edited or rejected by the development team. This is even more straightforward than plain old comments. - the same infrastructure could be used for developers, with automatic checkin into subversion. - of course, plain old comments can be useful too. Concluding, a small caveat: The conversion/build tools are, of course, not complete yet. There are a number of XXX comments in the text, most of them indicate that the converter could not handle a situation -- that would have to be corrected once after conversion is done. Waiting for comments! Cheers, Georg -- Thus spake the Lord: Thou shalt indent with four spaces. No more, no less. Four shall be the number of spaces thou shalt indent, and the number of thy indenting shall be four. Eight shalt thou not indent, nor either indent thou two, excepting that thou then proceed to four. Tabs are right out.

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Wither PEP 335 (Overloadable Boolean Operators)?
by Jim Jewett 25 May '07

25 May '07

Greg, If you do update this PEP, please update the __not__ portion as well, at least regarding possible return values. It currently says that __not__ can return NotImplemented, which falls back to the current semantics. (Why? to override an explicit __not__? Then why not just put the current semantics on __object__, and override by calling that directly?) It does not yet say what will happen for objects that return something else outside of {True, False}, such as class AntiBool(object): def __not__(self): return self Is that OK, because "not not X" should now be spelled "bool(x)", and you haven't allowed the overriding of __bool__? (And, if so, how does that work Py3K?) -jJ

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Re: [Python-Dev] [Python-3000] Wither PEP 335 (Overloadable Boolean Operators)?
by Phillip J. Eby 25 May '07

25 May '07

At 11:25 AM 5/25/2007 +0200, Neville Grech Neville Grech wrote: > >From a user's POV, I'm +1 on having overloadable boolean > functions. In many cases I had to resort to overload add or neg > instead of and & not, I foresee a lot of cases where the and > overload could be used to join objects which represent constraints. > Overloadable boolean operators could also be used to implement > other types of logic (eg: fuzzy logic). Constraining them to just > primitive binary operations in my view will be delimiting for a > myriad of use cases. > >Sure, in some cases, one could overload the neg operator instead of >the not but semantically they have different meanings. Actually, I think that most of the use cases for this PEP would be better served by being able to "quote" code, i.e. to create AST objects directly from Python syntax. Then, you can do anything you can do in a Python expression (including conditional expressions, generator expressions, yield expressions, lambdas, etc.) without having to introduce new special methods for any of that stuff. In fact, if new features are added to the language later, they automatically become available in the same way.

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Wither PEP 335 (Overloadable Boolean Operators)?
by Guido van Rossum 25 May '07

25 May '07

While reviewing PEPs, I stumbled over PEP 335 ( Overloadable Boolean Operators) by Greg Ewing. I am of two minds of this -- on the one hand, it's been a long time without any working code or anything. OTOH it might be quite useful to e.g. numpy folks. It is time to reject it due to lack of interest, or revive it! -- --Guido van Rossum (home page: http://www.python.org/~guido/)

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nodef
by Martin Blais 23 May '07

23 May '07

Hi I often have the need for a generic object to use as the default value for a function parameter, where 'None' is a valid value for the parameter. For example: _sentinel = object() def first(iterable, default=_sentinel): """Return the first element of the iterable, otherwise the default value (if specified). """ for elem in iterable: # thx to rhettinger for optim. return elem if default is _sentinel: raise StopIteration return default Here, 'default' could legally accept None, so I cannot use that as the default value, nor anything else as far as I'm concerned (I don't know what lives in the iterable, so why should I make assumptions?). Sometimes in the past I've create generic objects, declared a class, e.g.: class NoDef: pass def foo(default=NoDef): ... and lately I've even started using the names of builtin functions (it bothers me a little bit though, that I do that). I think Python needs a builtin for this very purpose. I propose 'nodef', a unique object whose sole purpose is to serve as a default value. It should be unique, in the same sense that 'None' is unique. Comments or alternative solutions?

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Return value from socket.fileno()
by Alan Kennedy 23 May '07

23 May '07

Dear all, I am writing to seek information about the socket.fileno() method, and opinions on how best to implement it on jython. On cpython, socket.fileno() returns a file descriptor, i.e. an integer index into an array of file objects. This integer is then passed to select.select and select.poll, to register interest in specified events on the socket, i.e. readability, writability, connectedness, etc. Importantly, it is possible to select and poll on a socket's file descriptor immediately after the socket is created, e.g. before it is connected and even before a non-blocking connect process has been started. This is problematic on java, because java has different classes for client and server sockets. Therefore, on jython, creation of the actual socket implementation is deferred until the user has called a method which commits the socket to being a client or server socket, e.g. connect, listen, etc. This means that there is no meaningful descriptor/channel that can be returned from fileno() until the nature of the socket is determined. Also, file descriptors have no meaning on java. Instead, java Selectors select on java.nio.channels.SelectableChannel objects. But, ideally, this should not matter: AFAICT, the return value from fileno should be simply an opaque handle which has no purpose other than to be handed to select and poll, to indicate interest in events on the associated socket. I have been thinking that the simplest way to implement socket.fileno() on jython is to return the actual socket object, i.e. return self. When this object is passed to select/poll as a parameter, the select/poll implementation would know to retrieve the underlying java SelectableChannel, if it exists yet. If it does not yet exist, because the socket is not yet commited to being a server or client socket, then it is simply excluded from the select/poll operation. The only problem with it is returning a non-integer from the fileno() method; instead a socket object would be returned. So the question I'm asking is: Does anyone know of existing cpython code which relies on the return value from socket.fileno() being an integer? Or code that would break if it were returned a socket instance instead of an integer? Thanks, Alan. P.S. If anyone is interested, a non-blocking sockets and select (and soon asyncore) implementation is currently residing in the jython sandbox. It is hoped that it will be included in jython 2.2rc1. More here http://wiki.python.org/jython/NewSocketModule

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Introduction and request for commit access to the sandbox.
by Alexandre Vassalotti 23 May '07

23 May '07

Hello, As some of you may already know, I will be working on Python for this year Google Summer of Code. My project is to merge the modules with a dual C and Python implementation, i.e. cPickle/pickle, cStringIO/StringIO and cProfile/profile [1]. This project is part of the standard library reorganization for Python 3000 [2]. And my mentor for this project is Brett Cannon. So first, let me introduce myself. I am currently a student from Quebec, Canada. I plan to make a career as a (hopefully good) programmer. Therefore, I dedicate a lot of my free time contributing to open source projects, like Ubuntu. I, recently, became interested by how compilers and interpreters work. So, I started reading Python's source code, which is one of the most well organized and comprehensive code base I have seen. This motivated me to start contributing to Python. However since school kept me fairly busy, I haven't had the chance to do anything other than providing support to Python's users in the #python FreeNode IRC channel. This year Summer of Code will give me the chance to do a significant contribution to Python, and to get started with Python code development as well. With that said, I would to request svn access to the sandbox for my work. I will use this access only for modifying stuff in the directory I will be assigned to. I would like to use the username "avassalotti" and the attached SSH2 public key for this access. One last thing, if you know semantic differences (other than the obvious ones) between the C and Python versions of the modules I need to merge, please let know. This will greatly simplify the merge and reduce the chances of later breaking. Cheers, -- Alexandre .. [1] Abstract of my application, Merge the C and Python implementations of the same interface (http://code.google.com/soc/psf/appinfo.html?csaid=C6768E09BEF7CCE2) .. [2] PEP 3108, Standard Library Reorganization, Cannon (http://www.python.org/dev/peps/pep-3108)

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-OO and Docstrings
by Georg Brandl 23 May '07

23 May '07

Bug #1722485 reports that Py 2.5+ doesn't ignore docstrings anymore if used with -OO. Attached patch should fix this. Georg

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Need Survey Answers from Core Developers
by Jeff Rush 22 May '07

22 May '07

Time is short and I'm still looking for answers to some questions about cPython, so that it makes a good showing in the Forrester survey. 1) How is the project governed? How does the community make decisions on what goes into a release? You know, I've been a member of the Python community for many years -- I know about PEPs, Guido as BDFL, and +1/-1. But I've never figured out exactly how -final- decisions are made on what goes into a release. I've never needed to, until now. Can someone explain in one paragraph? 2) Does the language have a formal defined release plan? I know Zope 3's release plan, every six months, but not that of Python. Is there a requirement to push a release out the door every N months, as some projects do, or is each release separately negotiated with developers around a planned set of features? 3) Some crude idea of how many new major and minor features were added in the last release? Yes, I know this is difficult -- the idea it so get some measure of the evolution/stability of cPython re features. Jython and IronPython are probably changing rapidly -- cPython, not such much. 4) How many committers to the cPython core are there? I don't have the necessary access to the pydotorg infrastructure to answer this -- can someone who does help me out here? Thanks for any one-line answers you can dash off to me today. Jeff Rush Python Advocacy Coordinator

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Python-Dev May 2007