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Python Enhancement Proposals

PEP 12 – Sample reStructuredText PEP Template

Author:
David Goodger <goodger at python.org>, Barry Warsaw <barry at python.org>, Brett Cannon <brett at python.org>
Status:
Active
Type:
Process
Created:
05-Aug-2002
Post-History:
30-Aug-2002

Table of Contents

Note

For those who have written a PEP before, there is a template (which is included as a file in the PEPs repository).

Abstract

This PEP provides a boilerplate or sample template for creating your own reStructuredText PEPs. In conjunction with the content guidelines in PEP 1, this should make it easy for you to conform your own PEPs to the format outlined below.

Note: if you are reading this PEP via the web, you should first grab the text (reStructuredText) source of this PEP in order to complete the steps below. DO NOT USE THE HTML FILE AS YOUR TEMPLATE!

The source for this (or any) PEP can be found in the PEPs repository, as well as via a link at the bottom of each PEP.

Rationale

If you intend to submit a PEP, you MUST use this template, in conjunction with the format guidelines below, to ensure that your PEP submission won’t get automatically rejected because of form.

ReStructuredText provides PEP authors with useful functionality and expressivity, while maintaining easy readability in the source text. The processed HTML form makes the functionality accessible to readers: live hyperlinks, styled text, tables, images, and automatic tables of contents, among other advantages.

How to Use This Template

To use this template you must first decide whether your PEP is going to be an Informational or Standards Track PEP. Most PEPs are Standards Track because they propose a new feature for the Python language or standard library. When in doubt, read PEP 1 for details, or open a tracker issue on the PEPs repo to ask for assistance.

Once you’ve decided which type of PEP yours is going to be, follow the directions below.

  • Make a copy of this file (the .rst file, not the HTML!) and perform the following edits. Name the new file pep-9999.rst if you don’t yet have a PEP number assignment, or pep-NNNN.rst if you do. Those with push permissions are welcome to claim the next available number (ignoring the special blocks 3000 and 8000, and a handful of special allocations - currently 666, 754, and 801) and push it directly.
  • Replace the “PEP: 12” header with “PEP: 9999” or “PEP: NNNN”, matching the file name. Note that the file name should be padded with zeros (eg pep-0012.rst), but the header should not (PEP: 12).
  • Change the Title header to the title of your PEP.
  • Change the Author header to include your name, and optionally your email address. Be sure to follow the format carefully: your name must appear first, and it must not be contained in parentheses. Your email address may appear second (or it can be omitted) and if it appears, it must appear in angle brackets. It is okay to obfuscate your email address.
  • If none of the authors are Python core developers, include a Sponsor header with the name of the core developer sponsoring your PEP.
  • Add the direct URL of the PEP’s canonical discussion thread (on e.g. Python-Dev, Discourse, etc) under the Discussions-To header. If the thread will be created after the PEP is submitted as an official draft, it is okay to just list the venue name initially, but remember to update the PEP with the URL as soon as the PEP is successfully merged to the PEPs repository and you create the corresponding discussion thread. See PEP 1 for more details.
  • Change the Status header to “Draft”.
  • For Standards Track PEPs, change the Type header to “Standards Track”.
  • For Informational PEPs, change the Type header to “Informational”.
  • For Standards Track PEPs, if your feature depends on the acceptance of some other currently in-development PEP, add a Requires header right after the Type header. The value should be the PEP number of the PEP yours depends on. Don’t add this header if your dependent feature is described in a Final PEP.
  • Change the Created header to today’s date. Be sure to follow the format carefully: it must be in dd-mmm-yyyy format, where the mmm is the 3 English letter month abbreviation, i.e. one of Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec.
  • For Standards Track PEPs, after the Created header, add a Python-Version header and set the value to the next planned version of Python, i.e. the one your new feature will hopefully make its first appearance in. Do not use an alpha or beta release designation here. Thus, if the last version of Python was 2.2 alpha 1 and you’re hoping to get your new feature into Python 2.2, set the header to:
    Python-Version: 2.2
    
  • Leave Post-History alone for now; you’ll add dates and corresponding links to this header each time you post your PEP to the designated discussion forum (and update the Discussions-To header with said link, as above). For each thread, use the date (in the dd-mmm-yyy format) as the linked text, and insert the URLs inline as anonymous reST hyperlinks, with commas in between each posting.

    If you posted threads for your PEP on August 14, 2001 and September 3, 2001, the Post-History header would look like, e.g.:

    Post-History: `14-Aug-2001 <https://www.example.com/thread_1>`__,
                  `03-Sept-2001 <https://www.example.com/thread_2>`__
    

    You should add the new dates/links here as soon as you post a new discussion thread.

  • Add a Replaces header if your PEP obsoletes an earlier PEP. The value of this header is the number of the PEP that your new PEP is replacing. Only add this header if the older PEP is in “final” form, i.e. is either Accepted, Final, or Rejected. You aren’t replacing an older open PEP if you’re submitting a competing idea.
  • Now write your Abstract, Rationale, and other content for your PEP, replacing all this gobbledygook with your own text. Be sure to adhere to the format guidelines below, specifically on the prohibition of tab characters and the indentation requirements. See “Suggested Sections” below for a template of sections to include.
  • Update your Footnotes section, listing any footnotes and non-inline link targets referenced by the text.
  • Run ./build.py to ensure the PEP is rendered without errors, and check that the output in build/pep-9999.html looks as you intend.
  • Create a pull request against the PEPs repository.

For reference, here are all of the possible header fields (everything in brackets should either be replaced or have the field removed if it has a leading * marking it as optional and it does not apply to your PEP):

PEP: [NNN]
Title: [...]
Author: [Full Name <email at example.com>]
Sponsor: *[Full Name <email at example.com>]
PEP-Delegate:
Discussions-To: [URL]
Status: Draft
Type: [Standards Track | Informational | Process]
Content-Type: text/x-rst
Requires: *[NNN]
Created: [DD-MMM-YYYY]
Python-Version: *[M.N]
Post-History: [`DD-MMM-YYYY <URL>`__]
Replaces: *[NNN]
Superseded-By: *[NNN]
Resolution:

ReStructuredText PEP Formatting Requirements

The following is a PEP-specific summary of reStructuredText syntax. For the sake of simplicity and brevity, much detail is omitted. For more detail, see Resources below. Literal blocks (in which no markup processing is done) are used for examples throughout, to illustrate the plaintext markup.

General

Lines should usually not extend past column 79, excepting URLs and similar circumstances. Tab characters must never appear in the document at all.

Section Headings

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. Section titles must be adorned with an underline, a single repeated punctuation character, which begins in column zero and must extend at least as far as the right edge of the title text (4 characters minimum). First-level section titles are underlined with “=” (equals signs), second-level section titles with “-” (hyphens), and third-level section titles with “’” (single quotes or apostrophes). For example:

First-Level Title
=================

Second-Level Title
------------------

Third-Level Title
'''''''''''''''''

If there are more than three levels of sections in your PEP, you may insert overline/underline-adorned titles for the first and second levels as follows:

============================
First-Level Title (optional)
============================

-----------------------------
Second-Level Title (optional)
-----------------------------

Third-Level Title
=================

Fourth-Level Title
------------------

Fifth-Level Title
'''''''''''''''''

You shouldn’t have more than five levels of sections in your PEP. If you do, you should consider rewriting it.

You must use two blank lines between the last line of a section’s body and the next section heading. If a subsection heading immediately follows a section heading, a single blank line in-between is sufficient.

The body of each section is not normally indented, although some constructs do use indentation, as described below. Blank lines are used to separate constructs.

Paragraphs

Paragraphs are left-aligned text blocks separated by blank lines. Paragraphs are not indented unless they are part of an indented construct (such as a block quote or a list item).

Inline Markup

Portions of text within paragraphs and other text blocks may be styled. For example:

Text may be marked as *emphasized* (single asterisk markup,
typically shown in italics) or **strongly emphasized** (double
asterisks, typically boldface).  ``Inline literals`` (using double
backquotes) are typically rendered in a monospaced typeface.  No
further markup recognition is done within the double backquotes,
so they're safe for any kind of code snippets.

Block Quotes

Block quotes consist of indented body elements. For example:

This is a paragraph.

    This is a block quote.

    A block quote may contain many paragraphs.

Block quotes are used to quote extended passages from other sources. Block quotes may be nested inside other body elements. Use 4 spaces per indent level.

Literal Blocks

Literal blocks are used for code samples and other preformatted text. To indicate a literal block, preface the indented text block with “::” (two colons), or use the .. code-block:: directive. Indent the text block by 4 spaces; the literal block continues until the end of the indentation. For example:

This is a typical paragraph.  A literal block follows.

::

    for a in [5, 4, 3, 2, 1]:  # this is program code, shown as-is
        print(a)
    print("it's...")

::” is also recognized at the end of any paragraph; if not immediately preceded by whitespace, one colon will remain visible in the final output:

This is an example::

    Literal block

By default, literal blocks will be syntax-highlighted as Python code. For specific blocks that contain code or data in other languages/formats, use the .. code-block:: language directive, substituting the “short name” of the appropriate Pygments lexer (or text to disable highlighting) for language. For example:

.. code-block:: rst

    An example of the ``rst`` lexer (i.e. *reStructuredText*).

For PEPs that predominantly contain literal blocks of a specific language, use the .. highlight:: language directive with the appropriate language at the top of the PEP body (below the headers and above the Abstract). All literal blocks will then be treated as that language, unless specified otherwise in the specific .. code-block. For example:

.. highlight:: c

Abstract
========

Here's some C code::

    printf("Hello, World!\n");

Lists

Bullet list items begin with one of “-”, “*”, or “+” (hyphen, asterisk, or plus sign), followed by whitespace and the list item body. List item bodies must be left-aligned and indented relative to the bullet; the text immediately after the bullet determines the indentation. For example:

This paragraph is followed by a list.

* This is the first bullet list item.  The blank line above the
  first list item is required; blank lines between list items
  (such as below this paragraph) are optional.

* This is the first paragraph in the second item in the list.

  This is the second paragraph in the second item in the list.
  The blank line above this paragraph is required.  The left edge
  of this paragraph lines up with the paragraph above, both
  indented relative to the bullet.

  - This is a sublist.  The bullet lines up with the left edge of
    the text blocks above.  A sublist is a new list so requires a
    blank line above and below.

* This is the third item of the main list.

This paragraph is not part of the list.

Enumerated (numbered) list items are similar, but use an enumerator instead of a bullet. Enumerators are numbers (1, 2, 3, …), letters (A, B, C, …; uppercase or lowercase), or Roman numerals (i, ii, iii, iv, …; uppercase or lowercase), formatted with a period suffix (“1.”, “2.”), parentheses (“(1)”, “(2)”), or a right-parenthesis suffix (“1)”, “2)”). For example:

1. As with bullet list items, the left edge of paragraphs must
   align.

2. Each list item may contain multiple paragraphs, sublists, etc.

   This is the second paragraph of the second list item.

   a) Enumerated lists may be nested.
   b) Blank lines may be omitted between list items.

Definition lists are written like this:

what
    Definition lists associate a term with a definition.

how
    The term is a one-line phrase, and the definition is one
    or more paragraphs or body elements, indented relative to
    the term.

Tables

Simple tables are easy and compact:

=====  =====  =======
  A      B    A and B
=====  =====  =======
False  False  False
True   False  False
False  True   False
True   True   True
=====  =====  =======

There must be at least two columns in a table (to differentiate from section titles). Column spans use underlines of hyphens (“Inputs” spans the first two columns):

=====  =====  ======
   Inputs     Output
------------  ------
  A      B    A or B
=====  =====  ======
False  False  False
True   False  True
False  True   True
True   True   True
=====  =====  ======

Text in a first-column cell starts a new row. No text in the first column indicates a continuation line; the rest of the cells may consist of multiple lines. For example:

=====  =========================
col 1  col 2
=====  =========================
1      Second column of row 1.
2      Second column of row 2.
       Second line of paragraph.
3      - Second column of row 3.

       - Second item in bullet
         list (row 3, column 2).
=====  =========================

Footnotes

Footnote references consist of a left square bracket, a label, a right square bracket, and a trailing underscore. Instead of a number, use a label of the form “#word”, where “word” is a mnemonic consisting of alphanumerics plus internal hyphens, underscores, and periods (no whitespace or other characters are allowed). For example:

Refer to The TeXbook [#TeXbook]_ for more information.

which renders as

Refer to The TeXbook [1] for more information.

Whitespace must precede the footnote reference. Leave a space between the footnote reference and the preceding word.

Use footnotes for additional notes, explanations and caveats, as well as for references to books and other sources not readily available online. Native reST hyperlink targets or inline hyperlinks in the text should be used in preference to footnotes for including URLs to online resources.

Footnotes begin with “.. “ (the explicit markup start), followed by the footnote marker (no underscores), followed by the footnote body. For example:

.. [#TeXbook] Donald Knuth's *The TeXbook*, pages 195 and 196.

which renders as

Footnotes and footnote references will be numbered automatically, and the numbers will always match.

Images

If your PEP contains a diagram or other graphic, you may include it in the processed output using the image directive:

.. image:: diagram.png

Any browser-friendly graphics format is possible; PNG should be preferred for graphics, JPEG for photos and GIF for animations. Currently, SVG must be avoided due to compatibility issues with the PEP build system.

For accessibility and readers of the source text, you should include a description of the image and any key information contained within using the :alt: option to the image directive:

.. image:: dataflow.png
   :alt: Data flows from the input module, through the "black box"
         module, and finally into (and through) the output module.

Comments

A comment is an indented block of arbitrary text immediately following an explicit markup start: two periods and whitespace. Leave the “..” on a line by itself to ensure that the comment is not misinterpreted as another explicit markup construct. Comments are not visible in the processed document. For example:

..
   This section should be updated in the final PEP.
   Ensure the date is accurate.

Escaping Mechanism

reStructuredText uses backslashes (”\”) to override the special meaning given to markup characters and get the literal characters themselves. To get a literal backslash, use an escaped backslash (”\\”). There are two contexts in which backslashes have no special meaning: literal blocks and inline literals (see Inline Markup above). In these contexts, no markup recognition is done, and a single backslash represents a literal backslash, without having to double up.

If you find that you need to use a backslash in your text, consider using inline literals or a literal block instead.

Canonical Documentation and Intersphinx

As PEP 1 describes, PEPs are considered historical documents once marked Final, and their canonical documentation/specification should be moved elsewhere. To indicate this, use the canonical-docs directive or an appropriate subclass (currently canonical-pypa-spec for packaging standards).

Furthermore, you can use Intersphinx references to other Sphinx sites, currently the Python documentation and packaging.python.org, to easily cross-reference pages, sections and Python/C objects. This works with both the “canonical” directives and anywhere in your PEP.

Add the directive between the headers and the first section of the PEP (typically the Abstract) and pass as an argument an Intersphinx reference of the canonical doc/spec (or if the target is not on a Sphinx site, a reST hyperlink).

For example, to create a banner pointing to the sqlite3 docs, you would write the following:

.. canonical-doc:: :mod:`python:sqlite3`

which would generate the banner:

Important

This PEP is a historical document. The up-to-date, canonical documentation can now be found at sqlite3.

See PEP 1 for how to propose changes.

Or for a PyPA spec, such as the Core metadata specifications, you would use:

.. canonical-pypa-spec:: :ref:`packaging:core-metadata`

which renders as:

Important

This PEP is a historical document. The up-to-date, canonical spec, Core metadata specifications, is maintained on the PyPA specs page.

See the PyPA specification update process for how to propose changes.

The argument accepts arbitrary reST, so you can include multiple linked docs/specs and name them whatever you like, and you can also include directive content that will be inserted into the text. The following advanced example:

.. canonical-doc:: the :ref:`python:sqlite3-connection-objects` and :exc:`python:~sqlite3.DataError` docs

    Also, see the :ref:`Data Persistence docs <persistence>` for other examples.

would render as:

Important

This PEP is a historical document. The up-to-date, canonical documentation can now be found at the Connection objects and sqlite3.DataError docs.

Also, see the Data Persistence docs for other examples.

See PEP 1 for how to propose changes.

Habits to Avoid

Many programmers who are familiar with TeX often write quotation marks like this:

`single-quoted' or ``double-quoted''

Backquotes are significant in reStructuredText, so this practice should be avoided. For ordinary text, use ordinary ‘single-quotes’ or “double-quotes”. For inline literal text (see Inline Markup above), use double-backquotes:

``literal text: in here, anything goes!``

Suggested Sections

Various sections are found to be common across PEPs and are outlined in PEP 1. Those sections are provided here for convenience.

PEP: <REQUIRED: pep number>
Title: <REQUIRED: pep title>
Author: <REQUIRED: list of authors' real names and optionally, email addrs>
Sponsor: <real name of sponsor>
PEP-Delegate: <PEP delegate's real name>
Discussions-To: <REQUIRED: URL of current canonical discussion thread>
Status: <REQUIRED: Draft | Active | Accepted | Provisional | Deferred | Rejected | Withdrawn | Final | Superseded>
Type: <REQUIRED: Standards Track | Informational | Process>
Content-Type: text/x-rst
Requires: <pep numbers>
Created: <date created on, in dd-mmm-yyyy format>
Python-Version: <version number>
Post-History: <REQUIRED: dates, in dd-mmm-yyyy format, and corresponding links to PEP discussion threads>
Replaces: <pep number>
Superseded-By: <pep number>
Resolution: <url>


Abstract
========

[A short (~200 word) description of the technical issue being addressed.]


Motivation
==========

[Clearly explain why the existing language specification is inadequate to address the problem that the PEP solves.]


Rationale
=========

[Describe why particular design decisions were made.]


Specification
=============

[Describe the syntax and semantics of any new language feature.]


Backwards Compatibility
=======================

[Describe potential impact and severity on pre-existing code.]


Security Implications
=====================

[How could a malicious user take advantage of this new feature?]


How to Teach This
=================

[How to teach users, new and experienced, how to apply the PEP to their work.]


Reference Implementation
========================

[Link to any existing implementation and details about its state, e.g. proof-of-concept.]


Rejected Ideas
==============

[Why certain ideas that were brought while discussing this PEP were not ultimately pursued.]


Open Issues
===========

[Any points that are still being decided/discussed.]


Footnotes
=========

[A collection of footnotes cited in the PEP, and a place to list non-inline hyperlink targets.]


Copyright
=========

This document is placed in the public domain or under the
CC0-1.0-Universal license, whichever is more permissive.

Resources

Many other constructs and variations are possible, both those supported by basic Docutils and the extensions added by Sphinx.

A number of resources are available to learn more about them:

If you have questions or require assistance with writing a PEP that the above resources don’t address, ping @python/pep-editors on GitHub, open an issue on the PEPs repository or reach out to a PEP editor directly.


Source: https://github.com/python/peps/blob/main/pep-0012.rst

Last modified: 2022-08-03 03:48:56 GMT