path: root/glep-1.txt

GLEP: 1
Title: GLEP Purpose and Guidelines
Version: $Revision: 1.1 $
Last-Modified: $Date: 2003/05/31 15:18:03 $
Author: Grant Goodyear
Status: Draft
Type: Informational
Content-Type: text/x-rst
Created: 31 May 2003
Post-History: 


What is a GLEP?
==============

GLEP stands for "Gentoo Linux Enhancement Proposal".  A GLEP is a design
document providing information to the Gentoo Linux community, or describing
a new feature for Gentoo Linux.  (The GLEP concept, and, in fact, 
much of the text of this document, is liberally stolen from Python's
`PEP-0001`_.) The GLEP should provide a concise technical
specification of the feature and rationale for the feature.

We intend GLEPs 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 GLEP
author is responsible for building consensus within the community and
documenting dissenting opinions.

Because the GLEPs are maintained as text files under CVS control, their
revision history is the historical record of the feature proposal
[1]_.


Kinds of GLEPs
=============

There are two kinds of GLEPs.  A Standards Track GLEP describes a new
feature or implementation for Python.  An Informational GLEP describes
a Python design issue, or provides general guidelines or information
to the Python community, but does not propose a new feature.
Informational GLEPs do not necessarily represent a Python community
consensus or recommendation, so users and implementors are free to
ignore Informational GLEPs or follow their advice.


GLEP Work Flow
=============

The GLEP editors assign GLEP numbers and change their status.  The
current GLEP editors are David Goodger and Barry Warsaw.  Please send
all GLEP-related email to <peps@python.org>.

The GLEP process begins with a new idea for Python.  It is highly
recommended that a single GLEP contain a single key proposal or new
idea.  The more focussed the GLEP, the more successful it tends to
be.  The GLEP editor reserves the right to reject GLEP proposals if they
appear too unfocussed or too broad.  If in doubt, split your GLEP into
several well-focussed ones.

Each GLEP must have a champion -- someone who writes the GLEP using the
style and format described below, shepherds the discussions in the
appropriate forums, and attempts to build community consensus around
the idea.  The GLEP champion (a.k.a. Author) should first attempt to
ascertain whether the idea is GLEP-able.  Small enhancements or patches
often don't need a GLEP and can be injected into the Python development
work flow with a patch submission to the SourceForge `patch manager`_
or `feature request tracker`_.

The GLEP champion then emails the GLEP editor <peps@python.org> with a
proposed title and a rough, but fleshed out, draft of the GLEP.  This
draft must be written in GLEP style as described below.

If the GLEP editor approves, he will assign the GLEP a number, label it
as Standards Track or Informational, give it status "Draft", and
create and check-in the initial draft of the GLEP.  The GLEP editor will
not unreasonably deny a GLEP.  Reasons for denying GLEP 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 GLEP-ability.

If a pre-GLEP is rejected, the author may elect to take the pre-GLEP to
the comp.lang.python newsgroup (a.k.a. python-list@python.org mailing
list) to help flesh it out, gain feedback and consensus from the
community at large, and improve the GLEP for re-submission.

The author of the GLEP is then responsible for posting the GLEP to the
community forums, and marshaling community support for it.  As updates
are necessary, the GLEP author can check in new versions if they have
CVS commit permissions, or can email new GLEP versions to the GLEP
editor for committing.

Standards Track GLEPs consists of two parts, a design document and a
reference implementation.  The GLEP should be reviewed and accepted
before a reference implementation is begun, unless a reference
implementation will aid people in studying the GLEP.  Standards Track
GLEPs must include an implementation -- in the form of code, patch, or
URL to same -- before it can be considered Final.

GLEP authors are responsible for collecting community feedback on a GLEP
before submitting it for review.  A GLEP that has not been discussed on
python-list@python.org and/or python-dev@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 GLEP author accept private comments in the
early design phases, etc.  GLEP authors should use their discretion
here.

Once the authors have completed a GLEP, they must inform the GLEP editor
that it is ready for review.  GLEPs are reviewed by the BDFL and his
chosen consultants, who may accept or reject a GLEP or send it back to
the author(s) for revision.  For a GLEP that is pre-determined 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 GLEP review,
first notifying the GLEP author(s) and giving them a chance to make
revisions.

For a GLEP 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 GLEP 2 [2]_ for
standard library module acceptance criteria.

Once a GLEP 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 GLEP can also be assigned status "Deferred".  The GLEP author or
editor can assign the GLEP this status when no progress is being made
on the GLEP.  Once a GLEP is deferred, the GLEP editor can re-assign it
to draft status.

A GLEP 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.

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

GLEP work flow is as follows::

    Draft -> Accepted -> Final -> Replaced
      ^
      +----> Rejected
      v
    Deferred

Some Informational GLEPs may also have a status of "Active" if they are
never meant to be completed.  E.g. GLEP 1 (this GLEP).


What belongs in a successful GLEP?
=================================

Each GLEP should have the following parts:

1. Preamble -- RFC 822 style headers containing meta-data about the
   GLEP, including the GLEP 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 GLEP must either be explicitly
   labelled as placed in the public domain (see this GLEP 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 GLEPs that want to
   change the Python language.  It should clearly explain why the
   existing language specification is inadequate to address the
   problem that the GLEP solves.  GLEP 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 GLEPs that introduce backwards
   incompatibilities must include a section describing these
   incompatibilities and their severity.  The GLEP must explain how the
   author proposes to deal with these incompatibilities.  GLEP
   submissions without a sufficient backwards compatibility treatise
   may be rejected outright.

8. Reference Implementation -- The reference implementation must be
   completed before any GLEP is given status "Final", but it need not
   be completed before the GLEP 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.


GLEP Formats and Templates
=========================

There are two GLEP formats available to authors: plaintext and
reStructuredText_.

Plaintext GLEPs are written in plain ASCII text, contain minimal
structural markup, and should adhere to a rigid style.  GLEP 9 contains
a boilerplate template [3]_ you can use to get started writing your
plaintext GLEP.

ReStructuredText_ GLEPs allow for rich markup that is still quite easy
to read, but results in much better-looking and more functional HTML.
GLEP 12 contains a boilerplate template [4]_ for use with
reStructuredText GLEPs.

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


GLEP Header Preamble
===================

Each GLEP 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. ::

    GLEP: <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 | Rejected |
             Final | Replaced>
    Type: <Informational | Standards Track>
  * 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>
  * Replaced-By: <pep number>

The Author header lists the names, and optionally the email addresses
of all the authors/owners of the GLEP.  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 GLEP, however new
GLEPs must use the mandated format above, and it is acceptable to
change to this format when GLEPs 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 GLEPs will be obscured as a defense against spam
harvesters.

While a GLEP is in private discussions (usually during the initial
Draft phase), a Discussions-To header will indicate the mailing list
or URL where the GLEP is being discussed.  No Discussions-To header is
necessary if the GLEP 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.

The Type header specifies the type of GLEP: Informational or Standards
Track.

The format of a GLEP is specified with a Content-Type header.  The
acceptable values are "text/plain" for plaintext GLEPs (see GLEP 9 [3]_)
and "text/x-rst" for reStructuredText GLEPs (see GLEP 12 [4]_).
Plaintext ("text/plain") is the default if no Content-Type header is
present.

The Created header records the date that the GLEP was assigned a
number, while Post-History is used to record the dates of when new
versions of the GLEP 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 GLEPs must have a Python-Version header which indicates
the version of Python that the feature will be released with.
Informational GLEPs do not need a Python-Version header.

GLEPs may have a Requires header, indicating the GLEP numbers that this
GLEP depends on.

GLEPs may also have a Replaced-By header indicating that a GLEP has been
rendered obsolete by a later document; the value is the number of the
GLEP that replaces the current document.  The newer GLEP must have a
Replaces header containing the number of the GLEP that it rendered
obsolete.


Reporting GLEP Bugs, or Submitting GLEP Updates
=============================================

How you report a bug, or submit a GLEP update depends on several
factors, such as the maturity of the GLEP, the preferences of the GLEP
author, and the nature of your comments.  For the early draft stages
of the GLEP, it's probably best to send your comments and changes
directly to the GLEP author.  For more mature, or finished GLEPs you may
want to submit corrections to the SourceForge `bug manager`_ or better
yet, the SourceForge `patch manager`_ so that your changes don't get
lost.  If the GLEP author is a SF developer, assign the bug/patch to
him, otherwise assign it to the GLEP editor.

When in doubt about where to send your changes, please check first
with the GLEP author and/or GLEP editor.

GLEP authors who are also SF committers, can update the GLEPs themselves
by using "cvs commit" to commit their changes.  Remember to also push
the formatted GLEP text out to the web by doing the following::

    % python pep2html.py -i NUM

where NUM is the number of the GLEP you want to push out.  See ::

    % python pep2html.py --help

for details.


Transferring GLEP Ownership
==========================

It occasionally becomes necessary to transfer ownership of GLEPs to a
new champion.  In general, we'd like to retain the original author as
a co-author of the transferred GLEP, 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 GLEP 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 GLEP.  We try to build consensus around a GLEP, but if
that's not possible, you can always submit a competing GLEP.

If you are interested in assuming ownership of a GLEP, send a message
asking to take over, addressed to both the original author and the GLEP
editor <peps@python.org>.  If the original author doesn't respond to
email in a timely manner, the GLEP editor will make a unilateral
decision (it's not like such decisions can't be reversed :).


References and Footnotes
========================

.. _PEP-0001: http://www.python.org/peps/pep-0001.html
.. [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 GLEP revisions via
   the SourceForge web site at
   http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/python/python/nondist/peps/

.. [2] GLEP 2, Procedure for Adding New Modules, Faassen
   (http://www.python.org/peps/pep-0002.html)

.. [3] GLEP 9, Sample Plaintext GLEP Template, Warsaw
   (http://www.python.org/peps/pep-0009.html)

.. [4] GLEP 12, Sample reStructuredText GLEP Template, Goodger, Warsaw
   (http://www.python.org/peps/pep-0012.html)

.. [5] The script referred to here is pep2html.py, which lives in the
   same directory in the CVS tree as the GLEPs themselves.  Try
   ``pep2html.py --help`` for details.  The URL for viewing GLEPs on
   the web is http://www.python.org/peps/.

.. _patch manager:
   http://sourceforge.net/tracker/?group_id=5470&atid=305470

.. _feature request tracker:
   http://sourceforge.net/tracker/?atid=355470&group_id=5470&func=browse

.. _Open Publication License: http://www.opencontent.org/openpub/

.. _reStructuredText: http://docutils.sourceforge.net/rst.html

.. _Docutils: http://docutils.sourceforge.net/

.. _bug manager:
   http://sourceforge.net/tracker/?group_id=5470&atid=105470


Copyright
=========

This document has been placed in the public domain.