通用

你必须遵守 Emacs 的惯例，在每句话的末尾加两个空格。你应该把你的段落填到第 70 栏，但在任何情况下，你的行都不能超过第 79 栏。如果你的代码样本超过了第 79 栏，你应该重写。

Tab 字符绝对不能出现在文件中。PEP 应该包括本 PEP 底部举例的标准 Emacs 句子。

节标题

PEP 的标题必须在第 0 栏开始，每个词的首字母必须像书名一样大写。首字母缩写应使用全大写。章节标题必须用下划线装饰，这是一个重复的标点符号，从第 0 栏开始，必须至少延伸到标题文本的右边缘（最少 4 个字符）。一级标题下划线为 “=”（等号），二级标题用 “-”（连字符），三级标题用 “’”（单引号或撇号）。 例如

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

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

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

如果你的 PEP 中有超过三层的章节，你可以为第一层和第二层插入下划线/下划线装饰的标题，如下

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

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

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

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

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

你的 PEP 中不应该有超过五级的章节。如果你有，你应该考虑重写它。

你必须在一节正文的最后一行和下一节标题之间使用两个空行。如果一个小节的标题紧随一个章节的标题之后，中间只需一个空行即可。

每一节的主体通常不缩进，尽管有些结构体确实使用缩进，如下所述。空行是用来分隔结构体的。

段落

段落是左对齐的文本块，由空行分隔。段落不缩进，除非它们是缩进结构的一部分（如引用块或列表项）。

行内标记

段落和其他文本块中的部分文本可以被定型。 例如

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.

块引用

段落和其他文本块中的部分文本可以被定型。 例如

This is a paragraph.

    This is a block quote.

    A block quote may contain many paragraphs.

方块引号用于引用其他来源的扩展段落。区块引号可以嵌套在其他主体元素中。每个缩进级别使用 4 个空格。

Literal Blocks

Literal blocks are used for code samples or preformatted ASCII art. To indicate a literal block, preface the indented text block with “::” (two colons). The literal block continues until the end of the indentation. Indent the text block by 4 spaces. 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..."
    # a literal block continues until the indentation ends

The paragraph containing only “::” will be completely removed from the output; no empty paragraph will remain. “::” is also recognized at the end of any paragraph. If immediately preceded by whitespace, both colons will be removed from the output. When text immediately precedes the “::”, one colon will be removed from the output, leaving only one colon visible (i.e., “::” will be replaced by “:”). For example, one colon will remain visible here:

Paragraph::

    Literal block

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).
=====  =========================

Hyperlinks

When referencing an external web page in the body of a PEP, you should include the title of the page in the text, with either an inline hyperlink reference to the URL or a footnote reference (see Footnotes below). Do not include the URL in the body text of the PEP.

Hyperlink references use backquotes and a trailing underscore to mark up the reference text; backquotes are optional if the reference text is a single word. For example:

In this paragraph, we refer to the `Python web site`_.

An explicit target provides the URL. Put targets in a References section at the end of the PEP, or immediately after the reference. Hyperlink targets begin with two periods and a space (the “explicit markup start”), followed by a leading underscore, the reference text, a colon, and the URL (absolute or relative):

.. _Python web site: http://www.python.org/

The reference text and the target text must match (although the match is case-insensitive and ignores differences in whitespace). Note that the underscore trails the reference text but precedes the target text. If you think of the underscore as a right-pointing arrow, it points away from the reference and toward the target.

The same mechanism can be used for internal references. Every unique section title implicitly defines an internal hyperlink target. We can make a link to the Abstract section like this:

Here is a hyperlink reference to the `Abstract`_ section.  The
backquotes are optional since the reference text is a single word;
we can also just write: Abstract_.

Footnotes containing the URLs from external targets will be generated automatically at the end of the References section of the PEP, along with footnote references linking the reference text to the footnotes.

Text of the form “PEP x” or “RFC x” (where “x” is a number) will be linked automatically to the appropriate URLs.

Footnotes

Footnote references consist of a left square bracket, a number, a right square bracket, and a trailing underscore:

This sentence ends with a footnote reference [1]_.

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

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 following the title. For example:

Refer to PEP 1 [2]_ for more information.

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

References
==========

.. [2] PEP 1, "PEP Purpose and Guidelines", Warsaw, Hylton
   (http://www.python.org/dev/peps/pep-0001)

If you decide to provide an explicit URL for a PEP, please use this as the URL template:

http://www.python.org/dev/peps/pep-xxxx

PEP numbers in URLs must be padded with zeros from the left, so as to be exactly 4 characters wide; however, PEP numbers in the text are never padded.

During the course of developing your PEP, you may have to add, remove, and rearrange footnote references, possibly resulting in mismatched references, obsolete footnotes, and confusion. Auto-numbered footnotes allow more freedom. 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 PEP 1 [#PEP-1]_ for more information.

References
==========

.. [#PEP-1] PEP 1, "PEP Purpose and Guidelines", Warsaw, Hylton

   http://www.python.org/dev/peps/pep-0001

Footnotes and footnote references will be numbered automatically, and the numbers will always match. Once a PEP is finalized, auto-numbered labels should be replaced by numbers for simplicity.

Images

If your PEP contains a diagram, you may include it in the processed output using the “image” directive:

.. image:: diagram.png

Any browser-friendly graphics format is possible: .png, .jpeg, .gif, .tiff, etc.

Since this image will not be visible to readers of the PEP in source text form, you should consider including a description or ASCII art alternative, using a comment (below).

Comments

A comment block 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 the benefit of those reading your PEP in source form, please consider including a descriptions of or ASCII art alternatives to any images you include. For example:

.. image:: dataflow.png

..
   Data flows from the input module, through the "black box"
   module, and finally into (and through) the output module.

The Emacs stanza at the bottom of this document is inside a comment.

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.