Mailman 3 September 2002 - Python-Dev

PEP 1, PEP Purpose and Guidelines
by barry＠zope.com 18 May '21

18 May '21

It has been a while since I posted a copy of PEP 1 to the mailing lists and newsgroups. I've recently done some updating of a few sections, so in the interest of gaining wider community participation in the Python development process, I'm posting the latest revision of PEP 1 here. A version of the PEP is always available on-line at http://www.python.org/peps/pep-0001.html Enjoy, -Barry -------------------- snip snip -------------------- PEP: 1 Title: PEP Purpose and Guidelines Version: $Revision: 1.36 $ Last-Modified: $Date: 2002/07/29 18:34:59 $ Author: Barry A. Warsaw, Jeremy Hylton Status: Active Type: Informational Created: 13-Jun-2000 Post-History: 21-Mar-2001, 29-Jul-2002 What is a PEP? PEP stands for Python Enhancement Proposal. A PEP is a design document providing information to the Python community, or describing a new feature for Python. The PEP should provide a concise technical specification of the feature and a rationale for the feature. We intend PEPs to be the primary mechanisms for proposing new features, for collecting community input on an issue, and for documenting the design decisions that have gone into Python. The PEP author is responsible for building consensus within the community and documenting dissenting opinions. Because the PEPs are maintained as plain text files under CVS control, their revision history is the historical record of the feature proposal[1]. Kinds of PEPs There are two kinds of PEPs. A standards track PEP describes a new feature or implementation for Python. An informational PEP describes a Python design issue, or provides general guidelines or information to the Python community, but does not propose a new feature. Informational PEPs do not necessarily represent a Python community consensus or recommendation, so users and implementors are free to ignore informational PEPs or follow their advice. PEP Work Flow The PEP editor, Barry Warsaw <peps(a)python.org>, assigns numbers for each PEP and changes its status. The PEP process begins with a new idea for Python. It is highly recommended that a single PEP contain a single key proposal or new idea. The more focussed the PEP, the more successfully it tends to be. The PEP editor reserves the right to reject PEP proposals if they appear too unfocussed or too broad. If in doubt, split your PEP into several well-focussed ones. Each PEP must have a champion -- someone who writes the PEP using the style and format described below, shepherds the discussions in the appropriate forums, and attempts to build community consensus around the idea. The PEP champion (a.k.a. Author) should first attempt to ascertain whether the idea is PEP-able. Small enhancements or patches often don't need a PEP and can be injected into the Python development work flow with a patch submission to the SourceForge patch manager[2] or feature request tracker[3]. The PEP champion then emails the PEP editor <peps(a)python.org> with a proposed title and a rough, but fleshed out, draft of the PEP. This draft must be written in PEP style as described below. If the PEP editor approves, he will assign the PEP a number, label it as standards track or informational, give it status 'draft', and create and check-in the initial draft of the PEP. The PEP editor will not unreasonably deny a PEP. Reasons for denying PEP status include duplication of effort, being technically unsound, not providing proper motivation or addressing backwards compatibility, or not in keeping with the Python philosophy. The BDFL (Benevolent Dictator for Life, Guido van Rossum) can be consulted during the approval phase, and is the final arbitrator of the draft's PEP-ability. If a pre-PEP is rejected, the author may elect to take the pre-PEP to the comp.lang.python newsgroup (a.k.a. python-list(a)python.org mailing list) to help flesh it out, gain feedback and consensus from the community at large, and improve the PEP for re-submission. The author of the PEP is then responsible for posting the PEP to the community forums, and marshaling community support for it. As updates are necessary, the PEP author can check in new versions if they have CVS commit permissions, or can email new PEP versions to the PEP editor for committing. Standards track PEPs consists of two parts, a design document and a reference implementation. The PEP should be reviewed and accepted before a reference implementation is begun, unless a reference implementation will aid people in studying the PEP. Standards Track PEPs must include an implementation - in the form of code, patch, or URL to same - before it can be considered Final. PEP authors are responsible for collecting community feedback on a PEP before submitting it for review. A PEP that has not been discussed on python-list(a)python.org and/or python-dev(a)python.org will not be accepted. However, wherever possible, long open-ended discussions on public mailing lists should be avoided. Strategies to keep the discussions efficient include, setting up a separate SIG mailing list for the topic, having the PEP author accept private comments in the early design phases, etc. PEP authors should use their discretion here. Once the authors have completed a PEP, they must inform the PEP editor that it is ready for review. PEPs are reviewed by the BDFL and his chosen consultants, who may accept or reject a PEP or send it back to the author(s) for revision. Once a PEP has been accepted, the reference implementation must be completed. When the reference implementation is complete and accepted by the BDFL, the status will be changed to `Final.' A PEP can also be assigned status `Deferred.' The PEP author or editor can assign the PEP this status when no progress is being made on the PEP. Once a PEP is deferred, the PEP editor can re-assign it to draft status. A PEP can also be `Rejected'. Perhaps after all is said and done it was not a good idea. It is still important to have a record of this fact. PEPs can also be replaced by a different PEP, rendering the original obsolete. This is intended for Informational PEPs, where version 2 of an API can replace version 1. PEP work flow is as follows: Draft -> Accepted -> Final -> Replaced ^ +----> Rejected v Deferred Some informational PEPs may also have a status of `Active' if they are never meant to be completed. E.g. PEP 1. What belongs in a successful PEP? Each PEP should have the following parts: 1. Preamble -- RFC822 style headers containing meta-data about the PEP, including the PEP number, a short descriptive title (limited to a maximum of 44 characters), the names, and optionally the contact info for each author, etc. 2. Abstract -- a short (~200 word) description of the technical issue being addressed. 3. Copyright/public domain -- Each PEP must either be explicitly labelled as placed in the public domain (see this PEP as an example) or licensed under the Open Publication License[4]. 4. Specification -- The technical specification should describe the syntax and semantics of any new language feature. The specification should be detailed enough to allow competing, interoperable implementations for any of the current Python platforms (CPython, JPython, Python .NET). 5. Motivation -- The motivation is critical for PEPs that want to change the Python language. It should clearly explain why the existing language specification is inadequate to address the problem that the PEP solves. PEP submissions without sufficient motivation may be rejected outright. 6. Rationale -- The rationale fleshes out the specification by describing what motivated the design and why particular design decisions were made. It should describe alternate designs that were considered and related work, e.g. how the feature is supported in other languages. The rationale should provide evidence of consensus within the community and discuss important objections or concerns raised during discussion. 7. Backwards Compatibility -- All PEPs that introduce backwards incompatibilities must include a section describing these incompatibilities and their severity. The PEP must explain how the author proposes to deal with these incompatibilities. PEP submissions without a sufficient backwards compatibility treatise may be rejected outright. 8. Reference Implementation -- The reference implementation must be completed before any PEP is given status 'Final,' but it need not be completed before the PEP is accepted. It is better to finish the specification and rationale first and reach consensus on it before writing code. The final implementation must include test code and documentation appropriate for either the Python language reference or the standard library reference. PEP Template PEPs are written in plain ASCII text, and should adhere to a rigid style. There is a Python script that parses this style and converts the plain text PEP to HTML for viewing on the web[5]. PEP 9 contains a boilerplate[7] template you can use to get started writing your PEP. Each PEP must begin with an RFC822 style header preamble. The headers must appear in the following order. Headers marked with `*' are optional and are described below. All other headers are required. PEP: <pep number> Title: <pep title> Version: <cvs version string> Last-Modified: <cvs date string> Author: <list of authors' real names and optionally, email addrs> * Discussions-To: <email address> Status: <Draft | Active | Accepted | Deferred | Final | Replaced> Type: <Informational | Standards Track> * Requires: <pep numbers> Created: <date created on, in dd-mmm-yyyy format> * Python-Version: <version number> Post-History: <dates of postings to python-list and python-dev> * Replaces: <pep number> * Replaced-By: <pep number> The Author: header lists the names and optionally, the email addresses of all the authors/owners of the PEP. The format of the author entry should be address(a)dom.ain (Random J. User) if the email address is included, and just Random J. User if the address is not given. If there are multiple authors, each should be on a separate line following RFC 822 continuation line conventions. Note that personal email addresses in PEPs will be obscured as a defense against spam harvesters. Standards track PEPs must have a Python-Version: header which indicates the version of Python that the feature will be released with. Informational PEPs do not need a Python-Version: header. While a PEP is in private discussions (usually during the initial Draft phase), a Discussions-To: header will indicate the mailing list or URL where the PEP is being discussed. No Discussions-To: header is necessary if the PEP is being discussed privately with the author, or on the python-list or python-dev email mailing lists. Note that email addresses in the Discussions-To: header will not be obscured. Created: records the date that the PEP was assigned a number, while Post-History: is used to record the dates of when new versions of the PEP are posted to python-list and/or python-dev. Both headers should be in dd-mmm-yyyy format, e.g. 14-Aug-2001. PEPs may have a Requires: header, indicating the PEP numbers that this PEP depends on. PEPs may also have a Replaced-By: header indicating that a PEP has been rendered obsolete by a later document; the value is the number of the PEP that replaces the current document. The newer PEP must have a Replaces: header containing the number of the PEP that it rendered obsolete. PEP Formatting Requirements PEP headings must begin in column zero and the initial letter of each word must be capitalized as in book titles. Acronyms should be in all capitals. The body of each section must be indented 4 spaces. Code samples inside body sections should be indented a further 4 spaces, and other indentation can be used as required to make the text readable. You must use two blank lines between the last line of a section's body and the next section heading. You must adhere to the Emacs convention of adding two spaces at the end of every sentence. You should fill your paragraphs to column 70, but under no circumstances should your lines extend past column 79. If your code samples spill over column 79, you should rewrite them. Tab characters must never appear in the document at all. A PEP should include the standard Emacs stanza included by example at the bottom of this PEP. A PEP must contain a Copyright section, and it is strongly recommended to put the PEP in the public domain. When referencing an external web page in the body of a PEP, you should include the title of the page in the text, with a footnote reference to the URL. Do not include the URL in the body text of the PEP. E.g. Refer to the Python Language web site [1] for more details. ... [1] http://www.python.org When referring to another PEP, include the PEP number in the body text, such as "PEP 1". The title may optionally appear. Add a footnote reference that includes the PEP's title and author. It may optionally include the explicit URL on a separate line, but only in the References section. Note that the pep2html.py script will calculate URLs automatically, e.g.: ... Refer to PEP 1 [7] for more information about PEP style ... References [7] PEP 1, PEP Purpose and Guidelines, Warsaw, Hylton http://www.python.org/peps/pep-0001.html If you decide to provide an explicit URL for a PEP, please use this as the URL template: http://www.python.org/peps/pep-xxxx.html PEP numbers in URLs must be padded with zeros from the left, so as to be exactly 4 characters wide, however PEP numbers in text are never padded. Reporting PEP Bugs, or Submitting PEP Updates How you report a bug, or submit a PEP update depends on several factors, such as the maturity of the PEP, the preferences of the PEP author, and the nature of your comments. For the early draft stages of the PEP, it's probably best to send your comments and changes directly to the PEP author. For more mature, or finished PEPs you may want to submit corrections to the SourceForge bug manager[6] or better yet, the SourceForge patch manager[2] so that your changes don't get lost. If the PEP author is a SF developer, assign the bug/patch to him, otherwise assign it to the PEP editor. When in doubt about where to send your changes, please check first with the PEP author and/or PEP editor. PEP authors who are also SF committers, can update the PEPs themselves by using "cvs commit" to commit their changes. Remember to also push the formatted PEP text out to the web by doing the following: % python pep2html.py -i NUM where NUM is the number of the PEP you want to push out. See % python pep2html.py --help for details. Transferring PEP Ownership It occasionally becomes necessary to transfer ownership of PEPs to a new champion. In general, we'd like to retain the original author as a co-author of the transferred PEP, but that's really up to the original author. A good reason to transfer ownership is because the original author no longer has the time or interest in updating it or following through with the PEP process, or has fallen off the face of the 'net (i.e. is unreachable or not responding to email). A bad reason to transfer ownership is because you don't agree with the direction of the PEP. We try to build consensus around a PEP, but if that's not possible, you can always submit a competing PEP. If you are interested assuming ownership of a PEP, send a message asking to take over, addressed to both the original author and the PEP editor <peps(a)python.org>. If the original author doesn't respond to email in a timely manner, the PEP editor will make a unilateral decision (it's not like such decisions can be reversed. :). References and Footnotes [1] This historical record is available by the normal CVS commands for retrieving older revisions. For those without direct access to the CVS tree, you can browse the current and past PEP revisions via the SourceForge web site at http://cvs.sourceforge.net/cgi-bin/cvsweb.cgi/python/nondist/peps/?cvsroot=… [2] http://sourceforge.net/tracker/?group_id=5470&atid=305470 [3] http://sourceforge.net/tracker/?atid=355470&group_id=5470&func=browse [4] http://www.opencontent.org/openpub/ [5] The script referred to here is pep2html.py, which lives in the same directory in the CVS tree as the PEPs themselves. Try "pep2html.py --help" for details. The URL for viewing PEPs on the web is http://www.python.org/peps/ [6] http://sourceforge.net/tracker/?group_id=5470&atid=305470 [7] PEP 9, Sample PEP Template http://www.python.org/peps/pep-0009.html Copyright This document has been placed in the public domain. Local Variables: mode: indented-text indent-tabs-mode: nil sentence-end-double-space: t fill-column: 70 End:

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RE: [Python-Dev] Those import related syntax errors again...
by Samuele Pedroni 23 Feb '05

23 Feb '05

Hi. [Mark Hammond] > The point isn't about my suffering as such. The point is more that > python-dev owns a tiny amount of the code out there, and I don't believe we > should put Python's users through this. > > Sure - I would be happy to "upgrade" all the win32all code, no problem. I > am also happy to live in the bleeding edge and take some pain that will > cause. > > The issue is simply the user base, and giving Python a reputation of not > being able to painlessly upgrade even dot revisions. I agree with all this. [As I imagined explicit syntax did not catch up and would require lot of discussions.] [GvR] > > Another way is to use special rules > > (similar to those for class defs), e.g. having > > > > <frag> > > y=3 > > def f(): > > exec "y=2" > > def g(): > > return y > > return g() > > > > print f() > > </frag> > > > > # print 3. > > > > Is that confusing for users? maybe they will more naturally expect 2 > > as outcome (given nested scopes). > > This seems the best compromise to me. It will lead to the least > broken code, because this is the behavior that we had before nested > scopes! It is also quite easy to implement given the current > implementation, I believe. > > Maybe we could introduce a warning rather than an error for this > situation though, because even if this behavior is clearly documented, > it will still be confusing to some, so it is better if we outlaw it in > some future version. > Yes this can be easy to implement but more confusing situations can arise: <frag> y=3 def f(): y=9 exec "y=2" def g(): return y return y,g() print f() </frag> What should this print? the situation leads not to a canonical solution as class def scopes. or <frag> def f(): from foo import * def g(): return y return g() print f() </frag> [Mark Hammond] > > This probably won't be a very popular suggestion, but how about pulling > > nested scopes (I assume they are at the root of the problem) > > until this can be solved cleanly? > > Agreed. While I think nested scopes are kinda cool, I have lived without > them, and really without missing them, for years. At the moment the cure > appears worse then the symptoms in at least a few cases. If nothing else, > it compromises the elegant simplicity of Python that drew me here in the > first place! > > Assuming that people really _do_ want this feature, IMO the bar should be > raised so there are _zero_ backward compatibility issues. I don't say anything about pulling nested scopes (I don't think my opinion can change things in this respect) but I should insist that without explicit syntax IMO raising the bar has a too high impl cost (both performance and complexity) or creates confusion. [Andrew Kuchling] > >Assuming that people really _do_ want this feature, IMO the bar should be > >raised so there are _zero_ backward compatibility issues. > > Even at the cost of additional implementation complexity? At the cost > of having to learn "scopes are nested, unless you do these two things > in which case they're not"? > > Let's not waffle. If nested scopes are worth doing, they're worth > breaking code. Either leave exec and from..import illegal, or back > out nested scopes, or think of some better solution, but let's not > introduce complicated backward compatibility hacks. IMO breaking code would be ok if we issue warnings today and implement nested scopes issuing errors tomorrow. But this is simply a statement about principles and raised impression. IMO import * in an inner scope should end up being an error, not sure about 'exec's. We will need a final BDFL statement. regards, Samuele Pedroni.

18 78

PEP: Support for System Upgrades
by M.-A. Lemburg 07 Jan '03

07 Jan '03

PEP: 0??? Title: Support for System Upgrades Version: $Revision: 0.0 $ Author: mal(a)lemburg.com (Marc-Andr? Lemburg) Status: Draft Type: Standards Track Python-Version: 2.3 Created: 19-Jul-2001 Post-History: Abstract This PEP proposes strategies to allow the Python standard library to be upgraded in parts without having to reinstall the complete distribution or having to wait for a new patch level release. Problem Python currently does not allow overriding modules or packages in the standard library per default. Even though this is possible by defining a PYTHONPATH environment variable (the paths defined in this variable are prepended to the Python standard library path), there is no standard way of achieving this without changing the configuration. Since Python's standard library is starting to host packages which are also available separately, e.g. the distutils, email and PyXML packages, which can also be installed independently of the Python distribution, it is desireable to have an option to upgrade these packages without having to wait for a new patch level release of the Python interpreter to bring along the changes. Proposed Solutions This PEP proposes two different but not necessarily conflicting solutions: 1. Adding a new standard search path to sys.path: $stdlibpath/system-packages just before the $stdlibpath entry. This complements the already existing entry for site add-ons $stdlibpath/site-packages which is appended to the sys.path at interpreter startup time. To make use of this new standard location, distutils will need to grow support for installing certain packages in $stdlibpath/system-packages rather than the standard location for third-party packages $stdlibpath/site-packages. 2. Tweaking distutils to install directly into $stdlibpath for the system upgrades rather than into $stdlibpath/site-packages. The first solution has a few advantages over the second: * upgrades can be easily identified (just look in $stdlibpath/system-packages) * upgrades can be deinstalled without affecting the rest of the interpreter installation * modules can be virtually removed from packages; this is due to the way Python imports packages: once it finds the top-level package directory it stay in this directory for all subsequent package submodule imports * the approach has an overall much cleaner design than the hackish install on top of an existing installation approach The only advantages of the second approach are that the Python interpreter does not have to changed and that it works with older Python versions. Both solutions require changes to distutils. These changes can also be implemented by package authors, but it would be better to define a standard way of switching on the proposed behaviour. Scope Solution 1: Python 2.3 and up Solution 2: all Python versions supported by distutils Credits None References None Copyright This document has been placed in the public domain. Local Variables: mode: indented-text indent-tabs-mode: nil End: -- Marc-Andre Lemburg CEO eGenix.com Software GmbH _______________________________________________________________________ eGenix.com -- Makers of the Python mx Extensions: mxDateTime,mxODBC,... Python Consulting: http://www.egenix.com/ Python Software: http://www.egenix.com/files/python/

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Re: [Python-Dev] Assign to errno allowed?
by Tim Peters 14 Oct '02

14 Oct '02

[Brad Clements] > ... > I would like to remind folks that on some platforms, one cannot > just use "errno = 0". On those platforms calling a function is > required to set errno. Except that errno=0 works fine on any platform with a standard- conforming C implementation, and this isn't even a fuzzy POSIX issue -- it's a requirement of the C standard. We can define piles of macros instead, but I expect that, as the years drag on, people will "forget" to use them.

6 10

Snapshot win32all builds of interest?
by Mark Hammond 10 Oct '02

10 Oct '02

I'm wondering if there is any interest in me making regular, basically untested win32all builds against the current Python CVS tree? It would be fairly simple for me to do - I run against CVS Python, so it is really just bundling up my latest built files into an installer .EXE. I would only do it for the current CVS trunk - ie, no Python 2.2 or earlier builds in this form. However, I would only bother if there were people willing to use it. I figure that if there aren't people in this forum who would use it, I won't find them anywhere ;) OTOH, people in this forum using CVS Python on Windows may prefer to use CVS and build their own win32all - I really have no clue ;) Thoughts? Mark.

5 5

PEP 282 Implementation
by Vinay Sajip 07 Oct '02

07 Oct '02

I've uploaded my logging module, the proposed implementation for PEP 282, for committer review, to the SourceForge patch manager: http://sourceforge.net/tracker/index.php?func=detail&aid=578494&group_id=547 0&atid=305470 I've assigned it to Mark Hammond as (a) he had posted some comments to Trent Mick's original PEP posting, and (b) Barry Warsaw advised not assigning to PythonLabs people on account of their current workload. The file logging.py is (apart from some test scripts) all that's supposed to go into Python 2.3. The file logging-0.4.6.tar.gz contains the module, an updated version of the PEP (which I mailed to Barry Warsaw on 26th June), numerous test/example scripts, TeX documentation etc. You can also refer to http://www.red-dove.com/python_logging.html Here's hoping for a speedy review :-) Regards, Vinay Sajip

5 12

How to add an encoding alias?
by Guido van Rossum 04 Oct '02

04 Oct '02

In the spambayes project we encountered some mail samples that use an encoding name ('ansi-x3-4-1968') that's not in encodings/aliases.py. (At least not until I added it to CVS yesterday.) I'd like the spambayes code base to be compatible with Python 2.2.1, so I like to add this one to the list of aliases. Is there an official API to add an alias, or do I just have to write import encodings.aliases encodings.aliases.aliases['ansi-x3-4-1968'] = 'ascii' ??? (BTW, there's an alias 'ansi_x3.4_1986' for ASCII. Was the ASCII standard renewed in 1986, or is that simply because there are encoding designators out there in real life that contain a typo?) --Guido van Rossum (home page: http://www.python.org/~guido/)

2 7

Re: User extendable literal modifiers ?!
by Gareth McCaughan 01 Oct '02

01 Oct '02

Marc-Andre Lemburg wrote: > Since these are numbers, it would be convenient if there were > some way to create them in form of literals, much like 123L > creates longs instead of integers or u"abc" gives you Unicode > instead of an 8-bit string. > > I was wondering whether it would be worth adding something > like a registry of literal modifiers to Python, so that > extensions can register new modifiers with the compiler, > e.g. > > sitecustomize.py: > def create_I_literal(literal_string): > return 'mx.Number.Integer(%s)' % literal_string > sys.register_numberlitmod('I', create_I_literal) > > test.py: > x = 123I * 456I > print x, 234I Too limiting. You'd only be able to do this for numbers, and it doesn't seem worth the pain just for numbers. Better would be user-definable *prefixes*. Common Lisp, for instance, makes it easy to customize the reader to recognize tokens of the form <hash> <character> <anything>. So you can arrange that #Q123,234,456:a(b)c turns into, erm, something terribly useful :-). Some of these characters are already taken for things like arrays [#(1 2 3), #2((1 2) (3 4))], "logical pathnames" (lightly abstracted filenames) [#"foo/bar/baz"], bit vectors [#*0001101011001], and so on. As perceptive readers will have noticed, you can splice a number between "#" and the magic character for special effects. Python could do something similar, though obviously "#" isn't a suitable character :-). Letting the user hijack the reader as completely as can be done in CL would probably be un-Pythonic, too. Here's a strawman suggestion. For any character "x" in some set I can't be bothered to specify, the Python tokenizer/parser will subject input of the form $x<string-literal> to special processing. The string-literal can be formed using any of {',",''',"""}. When I say "tokenizer/parser", I mean: the tokenizer will produce a special token encoding the character "x" and the contents of the string-literal. The parser will perform "special processing" in an attempt to turn it into a more normal token. The default "special processing" is to raise a SyntaxError. The user can define the special processing appropriate for a particular character "x" by making a function that interprets the string and feeding it to sys.register_dollar_handler. (In fact, anything callable will do.) The function will be passed two arguments: the character "x" and the string. Its return value will replace the $x"..." combination in the token stream, as a literal token. If an exception other than a SyntaxError is raised and not caught in the handler function then it will be silently replaced by a SyntaxError whose parameter has the form "ill-formed <xxx> literal". The value of "xxx" is defined when registering the handler. Handler functions are permitted to call "eval". Example: >>> def handle_rational(char, s): ... assert char == 'r' ... components = s.split('/') ... numerator, denominator = map(int, components) ... return Rational(numerator, denominator) ... >>> sys.register_dollar_handler('r', handle_rational, 'rational') >>> print $r"1/2" + $r"3/4" $r"5/4" >>> print $r"12345" File "<string>", line 1 print $r"12345" ^ SyntaxError: ill-formed rational literal >>> Alternatively: >>> class Rational: ... def __init__(self, x, y): ... if isinstance(x, str): ... x,y = map(int, y.split("/")) ... self._numerator, self._denominator = x,y ... [etc] ... >>> sys.register_dollar_handler('r', Rational, 'rational') Some dollar-syntax characters may be handled by Python itself or the standard library, or may be reserved for their use. It is possible for users to override them, but this should be considered bad practice. Registering a handler when one is already in place will produce a warning. To un-register a handler, pass None instead of the handler function. Possible applications: - Rational numbers. $r"123/234" - Regular expressions. $/"foo.*bar" - Dates and times. $t"2002-09-27 11:38" - Hostnames and ports. $h"www.google.com:80" Questions: - Is this insane? - Is "$" the best character? - Should there be a way to return tokens other than literal ones? For instance, identifiers or keywords? - Is the behaviour with exceptions correct? -- g

9 13

Documentation: type-vs.-function
by David Abrahams 30 Sep '02

30 Sep '02

I note that http://www.python.org/dev/doc/devel/lib/built-in-funcs.html#l2h-14 describes dict as a built-in function, whereas we all know that Guido's cool 2.2 changes made it into a type >>> dict <type 'dict'> Does this distinction matter? A little, I think. Calling it a function makes it sound like we're living in the past. Same goes for str, type, list, tuple, et. al. I realize that the type (especially <type 'type'>) acts like a function under many circumstances... un-important-ly y'rs, dave ----------------------------------------------------------- David Abrahams * Boost Consulting dave(a)boost-consulting.com * http://www.boost-consulting.com

4 3

Re: [Python-Dev] Documentation: type-vs.-function
by David Abrahams 30 Sep '02

30 Sep '02

From: "Alex Martelli" <aleax(a)aleax.it> > On Monday 30 September 2002 02:36 am, David Abrahams wrote: > > I note that > > http://www.python.org/dev/doc/devel/lib/built-in-funcs.html#l2h-14 > > describes dict as a built-in function, whereas we all know that Guido's > > cool 2.2 changes made it into a type > > > > >>> dict > > > > <type 'dict'> > > > > Does this distinction matter? A little, I think. Calling it a function > > makes it sound like we're living in the past. Same goes for str, type, > > list, tuple, et. al. I realize that the type (especially <type 'type'>) > > acts like a function under many circumstances... > > Trying to cover both 2.1 and 2.2 in the coming Nutshell, I've resorted to > periphrases such as "the built-in dict" or "the dict built-in" (the latter > uses "built-in" as a noun, I'm not yet sure the editor will let that go by). > > I've also tried to use 'callable' systematically instead of 'function' > wherever other callables (types, bound-methods, etc) can be substituted > in lieu of functions. In documenting 2.2 or 2.3 only, I think such hedging > is not warranted. It's important, when feasible, to clarify what built-ins > are types -- a type has MORE functionality than a function, after all (in > particular, one can subclass it, while one can't subclass a function). It's probably also worth noting that the dict type is not documented anywhere, except as a function. -Dave

1 0

Re: [Python-Dev] ATTENTION! Releasing Python 2.2.2 in a few weeks
by Michael Hudson 30 Sep '02

30 Sep '02

Guido van Rossum <guido(a)python.org> writes: > > > I'd like to release something called Python 2.2.2 in a few weeks (say, > > > around Oct 8; I like Tuesday release dates). > > > > One minor point of concern: I think Jack Jansen's on holiday. Perhaps > > we should wait for him to get back... > > He should be back by Oct 5 or 6 if what he told me of his schedule is > true. I'm not sure that it would matter much if MacPython 2.2.2 was > released a week after the main release. Maybe we should do one > release candidate anyway and give him space that way. OK, if you knew about this, then I'll assume you have it in hand... Cheers, M. -- Java is a WORA language! (Write Once, Run Away) -- James Vandenberg (on progstone(a)egroups.com) & quoted by David Rush on comp.lang.scheme

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Re: [Python-Dev] proposal for interfaces
by Esteban U.C.. Castro 30 Sep '02

30 Sep '02

Hi, I have just joined python-dev and I saw your very interesting proposal for implementing intefaces. > I have an idea for an interface mechnism for Python, and I'd like to see if > anyone likes it before writing an actual PEP. [...] I like it a lot! Anyway, if it can be implemented in python as is, what is the point of the PEP? Making the 'interface' root class and/or InterfaceError builtins, maybe? I have some comments which I thought I would bounce. I'll organize these attending to the activities they relate to. Don't hesitate to tell me if I'm sayig something stupid. :) Define an interface =================== In your example, it seems that class Foo(interface): def default_foo(self, a, b): "Docstring for foo method." print "Defaults can be handy." [I added the a, b arguments to illustrate one point below] Does the following: - Defines the requirement that all objects that implement Foo have a foo function - Defines that foo should accept arguments of the form (a, b) maybe? - Sets a doc string for the foo method. - Sets a default implementation for the method. Some questions on this: - Can an interface only define method names (and maybe argument formats)? I think it would be handy to let it expose attributes. - Is method names (and maybe format of arguments) the only thing you can 'promise' in the interface? In other words, is that the only type of guarantee that code that works against the interface can get? I think a __check__(self, obj) special method in interfaces would be a simple way to boost their flexibility. - For the uses you have given to the prefix_methodname notation so far, I don't think it's really needed. Isn't the following sufficient? class Foo(interface): def foo(self, a, b): "foo docstring" # nothing here; no default definition def bar(self, a, b): pass # no docstring, _empty definition_ This has the side effect that a method with no default definition and no doc string is a SyntaxError. Is this too bad? - It would maybe be hard to figure out what such a method is supposed to do, so you _should_ provide a docstring. - If you're in a hurry, an empty docstring will do the trick. While in 'quick and dirty mode' you probably won't be using interfaces a lot, anyway. Defaults look indeed useful, but the really crucial aspect to lay down in an interface definition is what does it guarantee on the objects that implement it. If amalgamating this with default defs would otherwise obscure it (there's another issue I'm addressing below), I think defaults belong more properly to a class that implements the interface, not to the interface definition itself. I guess knowing what other uses you have in mind for the prefix_methodname notation could be useful to decide whether it's warranted. Check whether an object implements an interface ===============================================

3 2

proposal for interfaces (errata)
by Esteban U.C.. Castro 30 Sep '02

30 Sep '02

g_f should be i2f. SPAM END :) ___________ Method renaming: ---------------- class I1(interface): def f(self): "" class I2(interface): def f(self, a, r, g, s): "" class SomeClass: def i_f(self): pass i1f.__implements__ = I1.f def g_f(self, a, r, g, s): pass i2f.__implements__ = I2.f [Note: if 'implements' is introduced as a keyword, as in the PEP, we=20 could just as well declare def g_f(self, a, r, g, s) implements I2.f: ... ]

1 0

bad formatting
by Esteban U.C.. Castro 30 Sep '02

30 Sep '02

Sorry again. Anyone knows of a 'sandbox' mailing list where I could experiment to fix the formatting problems?

1 0

proposal for interfaces
by Esteban U.C.. Castro 30 Sep '02

30 Sep '02

Thanks for your reply-- and thanks for taking the work of fixing the formatting in the quotations. I thought it would maybe be considered spam to send the message again just to fix the mess. (I think I know what caused the problem last time; I hope this one reads fine). Is there some sort of policy on this? > Well, aside from the ego boost of having my very own PEP, I think the > nature of interfaces is such that they're vastly more useful if lots > of people use them. Putting something in the standard distribution > almost guarantees that. Agreed. I was just curious about what is exactly that _something_ you want to put in the standard distribution. Just a recommendation on the docs? Have some of the existing modules refactored to use this method? [P.S.: I'm afraid your ego will have to give up on having your own interfaces PEP, since there is already one. See below.] I don't know if there are precedents of code practices being 'officially' endorsed by the python development team, when it implies no changes to either the language or the standard library. To start with a non-intrusive addition, I can think of a module defining precisely the interfaces of builtin types, and other commonplace de facto interfaces that already exist in the standard library. Imagine you want to use a function that takes a builtin type, but you want to pass your own fake instance. Making it just inherit the builtin type is an option, but maybe that's not practical, or yours is, too, a type not implemented in python, or you don't want to inherit the behavior of the builtin type. Having the interface formalized somewhere will help you know what will be expected from your custom object. Most 'interfaces' in standard python libraries (eg. iterable, iterator, stream...). are really simple, and it has worked quite well to have them as just de facto. I think code checking for an interface would be more expressive than code checking for method names or just trying to use the object and catch exceptions (you can still do this for other reasons if you want). The latter also relies on everyone knowing and agreeing on what makes an int an int, and a list a list. Now, many functions take lists, but only use a subset of the list interface. It would be handy if common subsets of (e.g.) the list interface could be identified and formalized in a standard module. We could define a SimpleReadList that would only guarantee getting items by index, a SliceRWDList() that would guarantee index and slice getting, setting, and deletion, and the complete List interface with all the append, insert, sort methods. [Note: of course it wouldn't be done like this, but I don't have a good idea of what are the most commonly used subsets of the list interface. Names ugly on purpose, so you won't take them seriously :).] This is also and example of why I see the usefulness or implicit interface satisfaction. This way interface definitions can have 'retroactive' effect, so you don't have to mess with the builtin types at all, in order to define how they interact with other objects (this is, to define and use their interfaces). > As much as I love Python, sometimes I really miss the rigor of more > stongly-typed languages, so rather than trying to make something > very Pythonic, I've tried to go the opposite direction in order to > complent what's there already. It looks like you are not alone in this-- or at least others have been where you are. You may want to take a look at the homepage for this (retired) Special Interest Group: http://www.python.org/sigs/types-sig/ While looking for this, I found a PEP, proposed by this group, which addresses interfaces too: http://www.python.org/peps/pep-0245.html I think there's a point in continuing this discussion though, as > Dissenting Opinion > This PEP has not yet been discussed on python-dev. If this is not a good time/place to talk about this, I guess we'll be warned :). I got a strong deja-vu reading this PEP. It matches so closely some of the changes I proposed to your model, that I must have read it long ago and then forgotten about it. Still, this suffers from some statically-typed background and may have the problems I pointed about your proposal; it seems to limit itself to the functionality and needs of Java interfaces (the only example I am more or less familiar with). Since there is a group effort behind it, I guess they have taken this into account and still agreed on this solution for some reason; I haven't looked at the archives yet. Also, this PEP is less shy about proposing changes to the language itself. This is maybe a good idea; if one of the important features for the usefulness of interfaces is that they will be widely used, it would help if there was only one universally accepted way to use them. Endorsing one such way in the language itself should help. > Actually I wanted to have attributes, too (and operators, since they're > just methods). This brings up one of the uses I had in mind for the > prefixes in front of the method names. To add a property, you could do > something like this: > > doc_myProperty = "docstring for myproperty" > readonly_myOtherProperty = "docstring for a read-only property" > writeonly_myLastProperty = "docstring for write-only property" Again, why not just: # name access docstring myProperty = "rw", "docstring for myProperty" myOtherProperty = "r", "docstring for a read-only property" myLastProperty = "w", "docstring for write-only property" > This would require implementions to either have properties named > "myProperty", "myOtherProperty" and "myLastProperty", or define methods > named __get__myProperty, __set__myProperty, __get__myOtherProperty, and > __set__myLastProperty. It could just require that implementations can be called getattr and/or setattr (depending on the access declared). There is the problem to check setattr non-destructively when the object is read-only. Maybe this is an issue somewhere else too? I wish this can be solved to keep the syntax as simple as possible. > Something I didn't include in the original message was the > design-by-contract feature, which would allow pre- and postconditions to > be specified for any method, like this: > > def check_foo(self, a, b): > "docstring for foo" > if not (some precondition for foo): > raise ExceptionOfYourChoice > if not (some other precondition for foo): > raise DifferentExceptionOfYourChoice > return lambda result: (postconditions of foo) # optional I think the ability to set attributes on python functions, or builtin properties (I'd have to refresh my memory on these :) could be used for this. Either way, the syntax for the client user could be something like: class SomeInterface(interface): def foo(self, a, b): "foo doc" def bar(self, a, b): "bar doc" foo.__pre__ = some_checking_func # takes a, b, raises something if # they're wrong foo.__post__ = other_checking_func # takes the return value, makes sure # it's not broken bar.__around__ = yet_another_checking_func # this is called _instead_ of # the function, and _should_ # call the function in turn This makes it more explicit that __pre__, __post__ and/or __around__ are something that relates to foo in some way. Your second approach (bar, __default__bar) comes closer to this, and it may be more convenient than first defining the function, then assigning it. Having part of the name of an object have an special meaning is convenient but a bit hacky. I myself do it often, but I don't think I'd propose a standard based on that. A matter of personal taste, I guess. >> - For the uses you have given to the prefix_methodname notation so far, >> I don't think it's really needed. Isn't the following sufficient? >> >> class Foo(interface): >> def foo(self, a, b): >> "foo docstring" >> # nothing here; no default definition >> def bar(self, a, b): >> pass # no docstring, _empty definition_ > > Not IMHO, since I'd want methods with no implementation to raise > NotImplementedError instead of silently returning None. One this that > *could* be done to make the the simplest case (just a docstring?) > easier (and make the syntax look more Pythonic) would be this: The absence of 'pass' in an interface method (in foo) would be considered absence of any default implementation and therefore you'd get an InterfaceError when trying to validate/get proxy on the object if it doesn't implement that method. In second thought, I admit this is dirty, and I don't know if this magic is even possible. A more explicit approach could be: class Foo(interface): def foo(self, a, b): "foo docstring" raise NotImplementedError def bar(self, a, b): pass # no docstring, _empty definition_ Or, for consistency with the proposal above (and with the existing PEP): class Foo(interface): def foo(self, a, b): "foo docstring" # no definition allowed here, sorry def bar(self, a, b): "" # empty docstring required at the very least bar.__default__ = lambda a, b: None Now that I think about it, the __underscores__ could maybe be taken out for interface method special attributes. They remind us that we are looking at magic stuff that the 'system' will be using in special ways, but if you are not expected to assign arbitrary attributes to interface methods, then there is no ambiguity. Aesthetic choice, again. > I got the idea of defaults from Haskell, where it's common to see an > interface define methods with mutually recursive default definitions, > kind of like (to use a somewhat silly Python example) defining __eq__, > __ne__, __cmp__, etc. all in terms of one another and expecting > implementations to define enough of the methods that everything works. I like it! :) I may be being too purist at this, but I still think that doesn't belong in the interface definition. I admit putting defaults there is convenient, but I wish we could find a solution that is both convenient and keeps implementation details out of the interface definition. Although the existing interface PEP stresses the separation between interface and class, it provides one possible solution for this: it talks about a deferred() method (in interfaces) that will return a class that implements the interface. In the PEP, it seems this is only meant to provide error reporting, but I guess it could be put to good use in other ways. I admit I don't understand the 'deferred' name :), I'm not sure how that default class would be defined, and whether it is intended to be customizable in the PEP. Having a convenient, standard way to define a default class and associate it with an interface without looking like something intrinsic to it, _that_ would be, IMHO, the ideal solution. >> In your example: >> >> def foo_proc(foo_arg): >> foo_proxy = Foo(foo_arg) >> ... >> x = foo_proxy.foo(a, b) >> >> [added a, b again] >> >> imagine foo_proc may only really cares that foo_arg is an object that >> has a foo() method that takes (a, b) arguments (this is all Foo >> guarantees). > > Here's where my compiled language bias comes in. If you only care the > foo_arg has a certain method, you don't want to use interfaces at all. > Using the interface doesn't just imply that foo_arg has a method named > foo, but also that the method satisfies the requirements laid out in the > interface definition. I agree; this case was only simplified for the sake of exposition. The point here is that the requirements laid out in the interface definition may possibly be checked on objects (as opposed to classes), at runtime (as opposed to, um, import-time :). If you really want to check the class you can do so in one specific interface. If you don't want the overhead of checking every time, and you know you won't be messing with class instances or objects, you may either check by class, or maybe even cache the results of checking on classes/objects. >> In the second case, if someone has been fiddling with foo_arg or some >> of its base classes, foo_arg.foo() may no longer exist or it may have >> a different signature. > > You can't really stop people from shooting themselves in the foot. > Making methods disappear is black magic in my book. Very true. This is of course no crucial point. Still, since method calls are always late-bound I think it only makes sense that restrictions on them _can_, at least, be late-checked. >> * I agree the declaration had better be included in the class >> definition, at least as an option. > > I agree, but as an option. The __implements__ alternative lets you fiddle with interfaces outside the class too: # SomeClass itself defined elsewhere SomeClass.__implements__ += (Foo,) All in all, the syntax I like the most so far is the one described in the existing PEP. >> * Declarative better than procedural, for this purpose. > > Whether this is declarative of procedural is mostly a matter of > perpective, IMHO. In my imagination, calls to bind occur only at the > module level, and almost always immediately after the class or interface > definition, so the "flavor" is declarative. You're right; an assignment is just as procedural as a function call. It was very personal aesthetic appreciation again; a function call looks more like it's "doing" something, to me. But that is very arguable. >> * Only classes (not instances) can declare that they implement an >> interface. > > Maybe there should be something like a "bindinstance" method as well. > I'm sure there's a way to do it, but I don't consider it a very high > priority. Me neither. I think declaration would typically be done in a per class, not per instance, basis. Still, due to the nature of python it is the instance (the object, really) who implements (or fails to) the interface. So I would add it, for completeness and to reflect this, *if* it would not require any specific syntax or additional complication. I think the way __implements__ would be searched would be natural for python users, since it is consistent with what is being done for __dict__, for example. > Good ideas. Your method has a lot of advantages, but it would be hard > (and messy) to make it do everything you can do with seprarate method > calls, and one thing I'm *very* reluctant to do is have two ways of > doing everything with only subtle or stylistic differences between them. I agree there should not be two ways. :> > The best thing to do here may be to allow your style for simple cases > (the 90% that would have required only a single "bind" call), but > use the method-based syntax for anything more elaborate, like method > renaming and unbinding subclasses. Method renaming and unbinding subclasses are supported in the alternative and rather easy; I guess the weird formatting obscured this :). Method renaming: ================ class I1(interface): def f(self): "" class I2(interface): def f(self, a, r, g, s): "" class SomeClass: def i_f(self): pass i1f.__implements__ = I1.f def g_f(self, a, r, g, s): pass i2f.__implements__ = I2.f [Note: if 'implements' is introduced as a keyword, as in the PEP, we could just as well declare def g_f(self, a, r, g, s) implements I2.f: ... ] Unbinding subclasses: ===================== class I1(interface): ... class I2interface): ... class Base: __implements__ = (I1, I2) class Sub(Base): # it would be more pretty to say (not I2,), but it would involve # some language hacking I guess, while (-I2,) only requires to # override __neg__ in the interface __implements__ = (-I2,) >> [using proxies] should be optional too, but your syntax does this >> nicely; you can call Foo() as an assertion of sorts and ignore the >> result. > > I think it would be very misleading to require than an object support a > formal interface but then expect it to also support methods not > specified in the interface. If this is what you want, the right thing > to do is derive a new interface from the old one that has the extra > functionality you need. As you pointed out, in the real world you won't be defining interfaces for very simple things like "has a write() method". This means, you may still want to use other forms of validation, or do without validation at all (for aspects of the code which are still in experimental phase, for example). You may even use the interface more informally as a mere sanity check. Anyway, method redirection almost enforces that the interface-specific functionality of an object be accessed through a proxy. Doing so looks like the right think to do anyway, so I don't consider this unfortunate at all. I like the proxy idea and the syntax you propose for it. The iterator example was a nice read, anyway :). Was this a typo? class Iterator(Iterable): Meant class Iterator(interface): ? As a conclussion, I am glad about the stress, in python, to generally make things easier for you, rather than paternalistically try to keep you from doing the evil. Since I came from Java, it took a bit using to, but I have seen python scaling nicely to rather big sized projects without this becoming a serious issue. I think there is a point to standardize and automate type checking in python, but I believe it can and should be done without betraying this philosophy. Enough ranting for today! :) Esteban.

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by herald＠ns1.nabitel.com 30 Sep '02

30 Sep '02

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Extension module difficulty w/pgen.
by Jonathan Riehl 30 Sep '02

30 Sep '02

Hi all, I know this is what I get for trying to integrate pgen into an extension module: I can't get it to link properly. I first saw the following problem on a FreeBSD box. Now, I have the following two external dependencies in my extension module (.../src/Modules/pgenmodule.c): extern grammar * _Py_pgen (node * n); extern grammar * _Py_meta_grammar (void); I added an entry to setup.py for it: exts.append( Extension('pgen', ['pgenmodule.c'])) Now when I run make, the extension module is not built, with the system complaining about being unable to resolve "_Py_meta_grammar", but not "_Py_pgen". When I run nm, I can see both symbols in libpython.2.3.a (these symbols are in pgen.c and metagrammar.c, both of which have been added to the libpython build target): ~/cvs/python/dist/src> nm ./libpython2.3.a | grep _Py_pgen [26] | 2676| 48|FUNC |GLOB |0 |2 |_Py_pgen ~/cvs/python/dist/src> nm ./libpython2.3.a | grep _Py_meta [36] | 0| 12|FUNC |GLOB |0 |2 |_Py_meta_grammar On the FreeBSD box, I was able to add "-L. -lpython2.3" to the command line, and this builds. However, when I use this hack on a Solaris platform, it complains about being unable to reserve a text offset for most if not all of the symbols in libpython. It seems to me that I should not have to use this workaround, which only works on one of the systems I use. Does anyone have an idea as to what I should do now? I am a bit confused by this, since Fred Drake's parser extension does not require any of this wackiness. As an aside, the code for the modules I am working on and the diffs are on Sourceforge (PEP 269 implementation), so you can play too, if so inclined. Thanks! -Jon

3 5

Re: FYI (was: watching mutables?)
by Samuele Pedroni 29 Sep '02

29 Sep '02

"Jiba" <jiba(a)tuxfamily.org> ha scritto nel messaggio news:3d96f25a$0$498$7a628cd7@news.club-internet.fr... > > Try EditObj (http://oomadness.tuxfamily.org/en/editobj) and look at the > module editobj.eventobj. > > It does exactely what you need, but it is quite a hack... FYI in Python 2.3: __class__ will be immutable for builtin types, and only mutable for (user) subtypes. See: http://mail.python.org/pipermail/python-checkins/2002-August/028681.html regards.

1 0

buitlins instance have modifiable __class__?
by Samuele Pedroni 29 Sep '02

29 Sep '02

question on bultin types (under 2.2): >>> d={} >>> class ndict(dict): ... __slots__ = () ... def __getitem__(self,k): ... print "__getitem__" ... return dict.__getitem__(self,k) ... >>> d.items() [] >>> d['a']=3 >>> d.__class__=ndict is intended to work? it seems it does, but is that the intention? >>> d['a'] __getitem__ 3 [ >>> exec "print a" in d 3 Ok, that is the non cooperative behavior I already know about. ] Thanks.

2 4

Weekly Python Bug/Patch Summary
by Skip Montanaro 29 Sep '02

29 Sep '02

Bug/Patch Summary ----------------- 290 open / 2889 total bugs (+5) 109 open / 1709 total patches (+3) New Bugs -------- property missing doc'd __name__ attr (2002-09-22) http://python.org/sf/612969 memory leaks when importing posix module (2002-09-23) http://python.org/sf/613222 win32 build_ext problem (2002-09-24) http://python.org/sf/614051 fpectl module broken on Linux (2002-09-24) http://python.org/sf/614060 Rewrite _reduce and _reconstructor in C (2002-09-25) http://python.org/sf/614555 LookupError etc. need API to get the key (2002-09-25) http://python.org/sf/614557 gethostbyname() blocks when threaded (2002-09-25) http://python.org/sf/614791 broken link in documentation (2002-09-25) http://python.org/sf/614821 socket.getfqdn() doesn't on Windows (2002-09-27) http://python.org/sf/615472 No __mod__ on str subclass (2002-09-27) http://python.org/sf/615506 Tkinter.Misc has no __contains__ method (2002-09-27) http://python.org/sf/615772 getdefaultlocale failure on OS X (2002-09-28) http://python.org/sf/616002 cPickle documentation incomplete (2002-09-28) http://python.org/sf/616013 list(xrange(sys.maxint / 4)) -> swapping (2002-09-28) http://python.org/sf/616019 New Patches ----------- koi8_u codec (2002-09-23) http://python.org/sf/613173 add unescape method to xml.sax.saxutils (2002-09-23) http://python.org/sf/613256 rm email package dependency on rfc822.py (2002-09-23) http://python.org/sf/613434 Bugfix: content-type header parsing (2002-09-23) http://python.org/sf/613605 OpenVMS patches (2002-09-24) http://python.org/sf/614055 fix for urllib2.AbstractBasicAuthHandler (2002-09-25) http://python.org/sf/614596 MSVC 7.0 compiler support (2002-09-25) http://python.org/sf/614770 build fixes for SCO (2002-09-26) http://python.org/sf/615069 acconfig.h out of date (2002-09-26) http://python.org/sf/615343 Closed Bugs ----------- New features need syntax (2001-08-17) http://python.org/sf/452222 ConfigParser has_option case sensitive (2002-05-29) http://python.org/sf/561822 resize readonly memory mapped file (2002-07-05) http://python.org/sf/577782 ConfigParser spaces in keys not read (2002-07-18) http://python.org/sf/583248 exec*() doesn't handle errors well (2002-08-20) http://python.org/sf/597797 Lone surrogates cause bad .pyc files (2002-09-17) http://python.org/sf/610783 2 bugs in turtle.py (2002-09-21) http://python.org/sf/612595 Closed Patches -------------- pyport.h, Wince and errno getter/setter (2002-01-19) http://python.org/sf/505846 Fix "file:" URL to have right no. of /'s (2002-08-06) http://python.org/sf/591713 bugfixes and cleanup for _strptime.py (2002-08-10) http://python.org/sf/593560 turtle tracer bugfixes and new functions (2002-08-14) http://python.org/sf/595111 select problems on Windows (2002-09-19) http://python.org/sf/611464 quietly select between 'less' and 'more' (2002-09-20) http://python.org/sf/612111

1 0

New logmerge feature
by Guido van Rossum 29 Sep '02

29 Sep '02

For those interested in poring over CVS logs, I've added a new feature to logmerge.py: a -b tag option that restricts the output to a specific branch tag. Use -b HEAD to show only the CVS HEAD (a.k.a. trunk). (The default is to show all revisions regardless of the branch on which they occur, which isn't always so easy if you're interested in a specific branch.) --Guido van Rossum (home page: http://www.python.org/~guido/)

1 0

sorry
by Esteban U.C.. Castro 29 Sep '02

29 Sep '02

phew! sorry about the formatting of the last one! :( Esteban.

5 4

Doc location question
by David Abrahams 29 Sep '02

29 Sep '02

Hi there, Is there a good reason that http://www.python.org/2.2.1/descrintro.html isn't also available as http://www.python.org/current/descrintro.html ? Maybe I don't understand the system. ----------------------------------------------------------- David Abrahams * Boost Consulting dave(a)boost-consulting.com * http://www.boost-consulting.com

2 1

Re: [Python-Dev] ATTENTION! Releasing Python 2.2.2 in a few weeks
by Michael Hudson 28 Sep '02

28 Sep '02

Guido van Rossum <guido(a)python.org> writes: > I'd like to release something called Python 2.2.2 in a few weeks (say, > around Oct 8; I like Tuesday release dates). One minor point of concern: I think Jack Jansen's on holiday. Perhaps we should wait for him to get back... Cheers, M. -- There's an aura of unholy black magic about CLISP. It works, but I have no idea how it does it. I suspect there's a goat involved somewhere. -- Johann Hibschman, comp.lang.scheme

2 1

Strange bug only happens with Python 2.2
by Gerhard Häring 28 Sep '02

28 Sep '02

This is somewhat off-topic, but I'm hoping maybe someone can give a hint why this only happens on Python 2.2.1. Ok, here's the story: I've had a bug report against our pyPgSQL database interface package that retrieving Large Objects doesn't work with Python 2.2.1. The reproducible traceback we get is: Traceback (most recent call last): File "p.py", line 20, in ? res = cs.fetchone() File "pyPgSQL/PgSQL.py", line 2672, in fetchone return self.__fetchOneRow() File "pyPgSQL/PgSQL.py", line 2281, in __fetchOneRow for _i in range(self.res.nfields): AttributeError: 'str' object has no attribute '__bases__' This traceback is quite obviously bogus, as self.res.nfields is a Python int and no strings are involved here whatsoever. After some debugging, I found that something very strange happens in a function call that happens in this for loop. Inside the for loop, a function typecast is called, which has this code within: if isinstance(value, PgBytea) or type(value) is PgLargeObjectType: This code is causing the problems which result in the bogus traceback later on. Now in my case, 'value' is of type PgLargeObjectType, which is a custom type from our extension module. PgBytea is a Python class. Now comes the first very strange observation: Swapping the checks, so that the 'type(value) is PgLargeObjectType' check comes first makes the problem go away. So my conclusion is that there's some problem with isinstance and my custom extension type. The second strange thing is that this only happens on Python 2.2.1 (Linux, FreeBSD, Windows), but _not_ on Python 2.1.3 or Python 2.3-CVS. Oh, the problem isn't tied to isinstance(value, PgBytea). Any isinstance check causes it later on. Of course I'm suspecting that there's some problem with the extension type. Looks like some internal interpreter data gets corrupted. No idea how to debug that, too. Does anybody have any tips where to look or how to debug this further? -- Gerhard

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