incubator-bloodhound-commits mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Apache Bloodhound" <>
Subject [Apache Bloodhound] Proposals added
Date Mon, 12 Nov 2012 00:01:32 GMT
Page "Proposals" was added by olemis
Comment: Expanded copy of PEP Purpose and Guidelines ( source :

= PEP 1 : PEP Purpose and Guidelines =


|| '''PEP''' || 1 ||
|| '''Title''' || ''PEP'' Purpose and Guidelines ||
|| '''Version''' || [ f3358939e05e]
|| '''Last-Modified''' || [ 2012-05-18 10:08:09
-0400 (Fri, 18 May 2012)] ||
|| '''Author''' || Barry Warsaw, Jeremy Hylton, David Goodger, Nick Coghlan ||
|| '''Status''' || Active ||
|| '''Type''' || Process ||
|| '''Content-Type''' || [ text/x-rst] ||
|| '''Created''' || 13-Jun-2000 ||
|| '''Post-History''' || 21-Mar-2001, 29-Jul-2002, 03-May-2003, 05-May-2012 ||


== What is a PEP? #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'' or its
processes or environment. 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 major 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 text files in a versioned repository, their revision history
is the historical record of the feature proposal ^[#id8 1]^ .

== PEP Types #pep-types

There are three kinds of PEP:

  - 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 implementers are free to ignore Informational PEPs or follow their advice.
  - A '''Process PEP''' describes a process surrounding ''Python'', or proposes a change to
(or an event in) a process. ''Process'' PEPs are like ''Standards Track'' PEPs but apply to
areas other than the ''Python'' language itself. They may propose an implementation, but not
to Python's codebase; they often require community consensus; unlike Informational PEPs, they
are more than recommendations, and users are typically not free to ignore them. Examples include
procedures, guidelines, changes to the decision-making process, and changes to the tools or
environment used in ''Python'' development. Any meta-PEP is also considered a ''Process''

== PEP Work Flow #pep-work-flow

=== Python's BDFL #python-s-bdfl

There are several reference in this ''PEP'' to the '''BDFL'''. This acronym stands for ''Benevolent
Dictator for Life'' and refers to ''Guido van Rossum'', the original creator of, and the final
design authority for, the ''Python'' programming language.

=== Submitting a PEP #submitting-a-pep

The ''PEP'' editors assign ''PEP'' numbers and change their status. Please send all PEP-related
email to <> (no cross-posting please). Also see [#pep-editor-responsibilities-workflow
PEP Editor Responsibilities & Workflow] below.

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. 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 ''Python'' [ issue tracker] . The more focused the
PEP, the more successful it tends to be. The ''PEP'' editor reserves the right to reject ''PEP''
proposals if they appear too unfocused or too broad. If in doubt, split your ''PEP'' into
several well-focused 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. Posting to the comp.lang.python newsgroup (a.k.a. mailing list) or the python-ideas mailing list is the best way to go
about this.

Vetting an idea publicly before going as far as writing a ''PEP'' is meant to save the potential
author time. Many ideas have been brought forward for changing ''Python'' that have been rejected
for various reasons. Asking the ''Python'' community first if an idea is original helps prevent
too much time being spent on something that is guaranteed to be rejected based on prior discussions
(searching the internet does not always do the trick). It also helps to make sure the idea
is applicable to the entire community and not just the author. Just because an idea sounds
good to the author does not mean it will work for most people in most areas where ''Python''
is used.

Once the champion has asked the ''Python'' community as to whether an idea has any chance
of acceptance, a draft ''PEP'' should be presented to python-ideas. This gives the author
a chance to flesh out the draft ''PEP'' to make properly formatted, of high quality, and to
address initial concerns about the proposal.

Following a discussion on python-ideas, the proposal should be sent to the python-dev list
with the draft ''PEP'' and the ''PEP'' editors <>. This draft must be
written in ''PEP'' style as described below, else it will be sent back without further regard
until proper formatting rules are followed.

If the ''PEP'' editor approves, they will assign the ''PEP'' a number, label it as Standards
Track, Informational, or Process, 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 can be consulted during the approval phase, and is the final arbiter of the draft's

Developers with hg push privileges for the [ PEP repository] may
claim ''PEP'' numbers directly by creating and committing a new PEP. When doing so, the developer
must handle the tasks that would normally be taken care of by the ''PEP'' editors (see [#pep-editor-responsibilities-workflow
PEP Editor Responsibilities & Workflow]). This includes ensuring the initial version meets
the expected standards for submitting a PEP. Alternately, even developers may choose to submit
PEPs through the ''PEP'' editors. When doing so, let the ''PEP'' editors know you have hg
push privileges and they can guide you through the process of updating the ''PEP'' repository

As updates are necessary, the ''PEP'' author can check in new versions if they have hg push
privileges, or can email new ''PEP'' versions to the ''PEP'' editors for publication.

Standards Track PEPs consist 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, a patch, or a 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. 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, setting up a wiki page, etc. ''PEP'' authors should use their discretion here.

=== PEP Review & Resolution #pep-review-resolution

Once the authors have completed a PEP, they may request a review for style and consistency
from the ''PEP'' editors. However, the content and final acceptance of the ''PEP'' must be
requested of the BDFL, usually via an email to the python-dev mailing list. 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. For a ''PEP'' that is predetermined to be acceptable (e.g.,
it is an obvious win as-is and/or its implementation has already been checked in) the BDFL
may also initiate a ''PEP'' review, first notifying the ''PEP'' author(s) and giving them
a chance to make revisions.

The final authority for ''PEP'' approval is the BDFL. However, whenever a new ''PEP'' is put
forward, any core developer that believes they are suitably experienced to make the final
decision on that ''PEP'' may offer to serve as the BDFL's delegate (or "PEP czar") for that
PEP. If their self-nomination is accepted by the other core developers and the BDFL, then
they will have the authority to approve (or reject) that PEP. This process happens most frequently
with PEPs where the BDFL has granted in principle approval for something to be done, but there
are details that need to be worked out before the ''PEP'' can be accepted.

If the final decision on a ''PEP'' is to be made by a delegate rather than directly by the
BDFL, this will be recorded by including the "BDFL-Delegate" header in the PEP.

For a ''PEP'' to be accepted it must meet certain minimum criteria. It must be a clear and
complete description of the proposed enhancement. The enhancement must represent a net improvement.
The proposed implementation, if applicable, must be solid and must not complicate the interpreter
unduly. Finally, a proposed enhancement must be "pythonic" in order to be accepted by the
BDFL. (However, "pythonic" is an imprecise term; it may be defined as whatever is acceptable
to the BDFL. This logic is intentionally circular.) See [
PEP 2] for standard library module acceptance criteria.

Once a ''PEP'' has been accepted, the reference implementation must be completed. When the
reference implementation is complete and incorporated into the main source code repository,
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. The "Withdrawn" status is similar - it
means that the ''PEP'' author themselves has decided that the ''PEP'' is actually a bad idea,
or has accepted that a competing proposal is a better alternative.

When a ''PEP'' is Accepted, Rejected or Withdrawn, the ''PEP'' should be updated accordingly.
In addition to updating the status field, at the very least the Resolution header should be
added with a link to the relevant post in the python-dev mailing list archives.

PEPs can also be superseded by a different PEP, rendering the original obsolete. This is intended
for Informational PEPs, where version 2 of an API can replace version 1.

The possible paths of the status of PEPs are as follows:

[[Image(, alt=PEP lifecycle, title=PEP
lifecycle, link=]]

Some Informational and Process PEPs may also have a status of "Active" if they are never meant
to be completed. E.g. ''PEP'' 1 (this PEP).

=== PEP Maintenance #pep-maintenance

In general, Standards track PEPs are no longer modified after they have reached the Final
state. Once a ''PEP'' has been completed, the Language and Standard Library References become
the formal documentation of the expected behavior.

Informational and Process PEPs may be updated over time to reflect changes to development
practices and other details. The precise process followed in these cases will depend on the
nature and purpose of the ''PEP'' being updated.

== What belongs in a successful PEP? #what-belongs-in-a-successful-pep

Each ''PEP'' should have the following parts:

  1. '''Preamble''' -- [ RFC 822] 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,
  2. '''Abstract''' -- a short (~200 word) description of the technical issue being addressed.
  3. '''Copyright/public domain''' -- Each ''PEP'' must either be explicitly labeled as placed
in the public domain (see this ''PEP'' as an example) or licensed under the [
Open Publication License].
  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, Jython,
''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 Formats and Templates #pep-formats-and-templates

There are two ''PEP'' formats available to authors: plaintext and [
reStructuredText]. Both are UTF-8-encoded text files.

Plaintext PEPs are written with minimal structural markup that adheres to a rigid style. [
PEP 9] contains a instructions and a template you can use to get started writing your plaintext

[ ReStructuredText] PEPs allow for rich markup that
is still quite easy to read, but results in much better-looking and more functional HTML.
''PEP'' 12 contains instructions and a template for reStructuredText PEPs.

There is a ''Python'' script that converts both styles of PEPs to HTML for viewing on the
web [#id12 5]. Parsing and conversion of plaintext PEPs is self-contained within the script.
reStructuredText PEPs are parsed and converted by [ Docutils]
code called from the script.

== PEP Header Preamble #pep-header-preamble

Each ''PEP'' must begin with an [ RFC 822] 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: <version string>
   Last-Modified: <date string>
   Author: <list of authors' real names and optionally, email addrs>
   * BDFL-Delegate: <PEP czar's real name>
   * Discussions-To: <email address>
   Status: <Draft | Active | Accepted | Deferred | Rejected | Withdrawn | Final | Superseded>
   Type: <Standards Track | Informational | Process>
   * Content-Type: <text/plain | text/x-rst>
   * 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>
   * Superseded-By: <pep number>
   * Resolution: <url>

The Author header lists the names, and optionally the email addresses of all the authors/owners
of the PEP. The format of the Author header value must be

  Random J. User <address@dom.ain>

if the email address is included, and just

  Random J. User

if the address is not given. For historical reasons the format ''address@dom.ain (Random J.
User)'' may appear in a PEP, however new PEPs must use the mandated format above, and it is
acceptable to change to this format when PEPs are updated.

If there are multiple authors, each should be on a separate line following [
RFC 2822] continuation line conventions. Note that personal email addresses in PEPs will be
obscured as a defense against spam harvesters.

The BDFL-Delegate field is used to record cases where the final decision to approve or reject
a ''PEP'' rests with someone other than the BDFL. (The delegate's email address is currently
omitted due to a limitation in the email address masking for reStructuredText PEPs)

Note: The Resolution header is required for Standards Track PEPs only. It contains a URL that
should point to an email message or other web resource where the pronouncement about the ''PEP''
is made.

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, python-ideas or python-dev email mailing lists. Note that email addresses in
the Discussions-To header will not be obscured.

The Type header specifies the type of PEP: '''Standards Track''', '''Informational''', or

The format of a ''PEP'' is specified with a '''Content-Type''' header. The acceptable values
are "text/plain" for plaintext PEPs (see [ PEP]) and
"text/x-rst" for reStructuredText PEPs (see [ PEP 12]).
Plaintext ("text/plain") is the default if no ''Content-Type'' header is present.

The Created header 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.

Standards Track PEPs must have a Python-Version header which indicates the version of ''Python''
that the feature will be released with. Informational and Process PEPs do not need a Python-Version

PEPs may have a Requires header, indicating the ''PEP'' numbers that this ''PEP'' depends

PEPs may also have a Superseded-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.

== Auxiliary Files  #auxiliary-files

PEPs may include auxiliary files such as diagrams. Such files must be named pep-XXXX-Y.ext,
where "XXXX" is the ''PEP'' number, "Y" is a serial number (starting at 1), and "ext" is replaced
by the actual file extension (e.g. "png").

== Reporting ''PEP'' Bugs, or Submitting ''PEP'' Updates #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 ''Python'' [ issue tracker] so that your changes don't get lost.
If the ''PEP'' author is a ''Python'' 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 ''Python'' committers can update the PEPs themselves by using "hg
push" to submit their changes.

== Transferring ''PEP'' Ownership #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 in assuming ownership of a PEP, send a message asking to take over,
addressed to both the original author and the ''PEP'' editor <>. 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't be reversed :).

== PEP Editor Responsibilities & Workflow #pep-editor-responsibilities-workflow

A ''PEP'' editor must subscribe to the <> list. All PEP-related correspondence
should be sent (or CC'd) to <> (but please do not cross-post!).

For each new ''PEP'' that comes in an editor does the following:

  - Read the ''PEP'' to check if it is ready: sound and complete. The ideas must make technical
sense, even if they don't seem likely to be accepted.
  - The title should accurately describe the content.
  - Edit the ''PEP'' for language (spelling, grammar, sentence structure, etc.), markup (for
reST PEPs), code style (examples should match [ PEP
8] & 7).

If the ''PEP'' isn't ready, the editor will send it back to the author for revision, with
specific instructions.

Once the ''PEP'' is ready for the repository, the ''PEP'' editor will:

  - Assign a ''PEP'' number (almost always just the next available number, but sometimes it's
a special/joke number, like 666 or 3141). (Clarification: For ''Python'' 3, we used numbers
in the 3000s for Py3k-specific proposals. But now that all new features go into ''Python''
3 only, we're back to using numbers in the 100s again. Remember that numbers below 100 are
  - Add the ''PEP'' to a local clone of the ''PEP'' repository. For mercurial work flow instructions,
follow [ The Python Developers Guide]

The mercurial repo for the peps is:


  - Run ./ and ./ <PEP Number> to ensure they are generated
without errors. If either triggers errors, then the web site will not be updated to reflect
the ''PEP'' changes.
  - Commit and push the new (or updated) PEP
  - Monitor to make sure the ''PEP'' gets added to the site properly.
  - Send email back to the ''PEP'' author with next steps (post to python-list & -dev).

Updates to existing PEPs also come in to Many ''PEP'' authors are not ''Python''
committers yet, so ''PEP'' editors do the commits for them.

Many PEPs are written and maintained by developers with write access to the ''Python'' codebase.
The ''PEP'' editors monitor the python-checkins list for ''PEP'' changes, and correct any
structure, grammar, spelling, or markup mistakes we see.

The editors don't pass judgment on PEPs. We merely do the administrative & editorial part.
Except for times like this, there's relatively low volume.

== Resources #resources

  - [ Index of Python Enhancement Proposals]
  - [ Following Python's Development]
  - [ Python Developer's Guide]
  - [ Frequently Asked Questions for Developers]

== References and Footnotes #references-and-footnotes

{{{#!span id="id8"
  1.  This historical record is available by the normal hg commands for retrieving older revisions,
and can also be browsed via HTTP here:
  2. PEP 2, Procedure for Adding New Modules, Faassen (
  3. ''PEP'' 9, Sample Plaintext ''PEP'' Template, Warsaw (
  4. ''PEP'' 12, Sample reStructuredText ''PEP'' Template, Goodger, Warsaw (
{{{#!span id="id12"
  5. The script referred to here is, the successor to, both of
which live in the same directory in the hg repo as the PEPs themselves. Try --help
for details. The URL for viewing PEPs on the web is

== Copyright #copyright

This document has been placed in the public domain.

Page URL: <>
Apache Bloodhound <>
The Apache Bloodhound (incubating) issue tracker

This is an automated message. Someone added your email address to be
notified of changes on 'Proposals' page.
If it was not you, please report to .

View raw message