空行

空行用来分割段落和其他元素。除了文本块（所有的空白字符都会保留），多个连续的空行等同于一个空行。如果标记能够明确区分出各元素，则可以结合缩进来省略空行。一篇文档的的第一行会被认为前面有一个空行，文档的最后一行会认为后面也有一个空行

缩进

缩进只用来表示块引用，定义（定义列表项目），和局部嵌套内容：

• 列表项内容(multi-line contents of list items, and multiple body elements within a list item,
  including nested lists),
• 文本块内容
• 明确的标记块内容

任意少于当前缩进级别的文本（未缩进或少于当前缩进（dedents））都会结束当前的缩进级别
所有的缩进都是有意义的，缩进级别必须一致。例如，缩进是块引用的唯一标记：

This is a top-level paragraph.

    This paragraph belongs to a first-level block quote.

    Paragraph 2 of the first-level block quote.

Multiple levels of indentation within a block quote will result in more complex structures:
一个块引用中的多个缩进级别会产生更复杂的结构：

This is a top-level paragraph.

    This paragraph belongs to a first-level block quote.

        This paragraph belongs to a second-level block quote.

Another top-level paragraph.

        This paragraph belongs to a second-level block quote.

    This paragraph belongs to a first-level block quote.  The
    second-level block quote above is inside this first-level
    block quote.

当一个段落或其他的结构包行文本时，这些行必须要左对齐：

This is a paragraph.  The lines of
this paragraph are aligned at the left.

    This paragraph has problems.  The
lines are not left-aligned.  In addition
  to potential misinterpretation, warning
    and/or error messages will be generated
  by the parser.

一些以标记开始的结构，并且这些结构的主体必须相对于标记缩进。对于使用简单比较的结构（无序列表，有序列表，脚注，引文，超链接目标，指令和注释），主体的缩进级别由第一行文本的位置决定。例如，无序列表主体必须至少相对于该列表的左侧缩进两列：

- This is the first line of a bullet list
  item's paragraph.  All lines must align
  relative to the first line.  [1]_

      This indented paragraph is interpreted
      as a block quote.

Because it is not sufficiently indented,
this paragraph does not belong to the list
item.

.. [1] Here's a footnote.  The second line is aligned
   with the beginning of the footnote label.  The ".."
   marker is what determines the indentation.

对于使用复杂标记的结构（字段列表和选项列表），标记可能包含任意的文本，标记后面第一行的缩进决定龄主体的左侧边缘。例如，字段列表可能包含非常长的标记：

:Hello: This field has a short field name, so aligning the field
        body with the first line is feasible.

:Number-of-African-swallows-required-to-carry-a-coconut: It would
    be very difficult to align the field body with the left edge
    of the first line.  It may even be preferable not to begin the
    body on the same line as the marker.

文档

文档树元素：文档。

The top-level element of a parsed reStructuredText document is the “document” element. After initial
parsing, the document element is a simple container for a document fragment, consisting of body elements, transitions,
and sections, but lacking a document title or other
bibliographic elements. The code that calls the parser may choose to run one or more optional post-parse transforms,
rearranging the document fragment into a complete document with a title and possibly other metadata elements
(author, date, etc.; see Bibliographic Fields).

DocTitle transform for
details.

Sections

Doctree elements: section, title.

Sections are identified through their titles, which are marked up with adornment: “underlines” below the
title text, or underlines and matching “overlines” above the title. An underline/overline is a single
repeated punctuation character that begins in column 1 and forms a line extending at least as far as the
right edge of the title text. Specifically, an underline/overline character may be any non-alphanumeric
printable 7-bit ASCII character [2]. When an overline is used, the length and character
used must match the underline. Underline-only adornment styles are distinct from overline-and-underline
styles that use the same character. There may be any number of levels of section titles, although some
output formats may have limits (HTML has 6 levels).

! " # $ % & ' ( ) * + , - . / : ; < = > ? @ [ \ ] ^ _ ` { | } ~

= - ` : . ' " ~ ^ _ * + #

Rather than imposing a fixed number and order of section title adornment styles, the order enforced will be
the order as encountered. The first style encountered will be an outermost title (like HTML H1), the second
style will be a subtitle, the third will be a subsubtitle, and so on.

Below are examples of section title styles:

===============
 Section Title
===============

---------------
 Section Title
---------------

Section Title
=============

Section Title
-------------

Section Title
`````````````

Section Title
'''''''''''''

Section Title
.............

Section Title
~~~~~~~~~~~~~

Section Title
*************

Section Title
+++++++++++++

Section Title
^^^^^^^^^^^^^

When a title has both an underline and an overline, the title text may be inset, as in the first two
examples above. This is merely aesthetic and not significant. Underline-only title text may not be
inset.

A blank line after a title is optional. All text blocks up to the next title of the same or higher level are
included in a section (or subsection, etc.).

All section title styles need not be used, nor need any specific section title style be used. However, a
document must be consistent in its use of section titles: once a hierarchy of title styles is established,
sections must use that hierarchy.

Each section title automatically generates a hyperlink target pointing to the section. The text of the
hyperlink target (the “reference name”) is the same as that of the section title. See Implicit Hyperlink Targets for a
complete description.

Sections may contain body elements, transitions, and nested sections.

Transitions

Doctree element: transition.

Instead of subheads, extra space or a type ornament between paragraphs may be used to mark text
divisions or to signal changes in subject or emphasis.

(The Chicago Manual of Style, 14th edition, section 1.80)

Transitions are commonly seen in novels and short fiction, as a gap spanning one or more lines, with or
without a type ornament such as a row of asterisks. Transitions separate other body elements. A transition
should not begin or end a section or document, nor should two transitions be immediately adjacent.

The syntax for a transition marker is a horizontal line of 4 or more repeated punctuation characters. The
syntax is the same as section title underlines without title text. Transition markers require blank lines
before and after:

Para.

----------

Para.

Unlike section title underlines, no hierarchy of transition markers is enforced, nor do differences in
transition markers accomplish anything. It is recommended that a single consistent style be used.

The processing system is free to render transitions in output in any way it likes. For example, horizontal
rules (<hr>) in HTML output would be an obvious choice.

Paragraphs

Doctree element: paragraph.

Paragraphs consist of blocks of left-aligned text with no markup indicating any other body element. Blank
lines separate paragraphs from each other and from other body elements. Paragraphs may contain inline markup.

Syntax diagram:

+------------------------------+
| paragraph                    |
|                              |
+------------------------------+

+------------------------------+
| paragraph                    |
|                              |
+------------------------------+

Bullet Lists

Doctree elements: bullet_list, list_item.

A text block which begins with a “*”, “+”, “-“, “•”, “‣”, or “⁃”, followed by whitespace, is a bullet list
item (a.k.a. “unordered” list item). 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 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.

Here are examples of incorrectly formatted bullet lists:

- This first line is fine.
A blank line is required between list items and paragraphs.
(Warning)

- The following line appears to be a new sublist, but it is not:
  - This is a paragraph continuation, not a sublist (since there's
    no blank line).  This line is also incorrectly indented.
  - Warnings may be issued by the implementation.

Syntax diagram:

+------+-----------------------+
| "- " | list item             |
+------| (body elements)+      |
       +-----------------------+

Enumerated Lists

Doctree elements: enumerated_list, list_item.

Enumerated lists (a.k.a. “ordered” lists) are similar to bullet lists, but use enumerators instead of
bullets. An enumerator consists of an enumeration sequence member and formatting, followed by whitespace.
The following enumeration sequences are recognized:

• arabic numerals: 1, 2, 3, … (no upper limit).
• uppercase alphabet characters: A, B, C, …, Z.
• lower-case alphabet characters: a, b, c, …, z.
• uppercase Roman numerals: I, II, III, IV, …, MMMMCMXCIX (4999).
• lowercase Roman numerals: i, ii, iii, iv, …, mmmmcmxcix (4999).

In addition, the auto-enumerator, “#”, may be used to automatically enumerate a list. Auto-enumerated lists
may begin with explicit enumeration, which sets the sequence. Fully auto-enumerated lists use arabic
numerals and begin with 1. (Auto-enumerated lists are new in Docutils 0.3.8.)

The following formatting types are recognized:

• suffixed with a period: “1.”, “A.”, “a.”, “I.”, “i.”.
• surrounded by parentheses: “(1)”, “(A)”, “(a)”, “(I)”, “(i)”.
• suffixed with a right-parenthesis: “1)”, “A)”, “a)”, “I)”, “i)”.

While parsing an enumerated list, a new list will be started whenever:

• An enumerator is encountered which does not have the same format and sequence type as the current
  list (e.g. “1.”, “(a)” produces two separate lists).
• The enumerators are not in sequence (e.g., “1.”, “3.” produces two separate lists).

It is recommended that the enumerator of the first list item be ordinal-1 (“1”, “A”, “a”, “I”, or “i”).
Although other start-values will be recognized, they may not be supported by the output format. A level-1
[info] system message will be generated for any list beginning with a non-ordinal-1 enumerator.

Lists using Roman numerals must begin with “I”/”i” or a multi-character value, such as “II” or “XV”. Any
other single-character Roman numeral (“V”, “X”, “L”, “C”, “D”, “M”) will be interpreted as a letter of the
alphabet, not as a Roman numeral. Likewise, lists using letters of the alphabet may not begin with “I”/”i”,
since these are recognized as Roman numeral 1.

The second line of each enumerated list item is checked for validity. This is to prevent ordinary paragraphs
from being mistakenly interpreted as list items, when they happen to begin with text identical to
enumerators. For example, this text is parsed as an ordinary paragraph:

A. Einstein was a really
smart dude.

However, ambiguity cannot be avoided if the paragraph consists of only one line. This text is parsed as an
enumerated list item:

A. Einstein was a really smart dude.

If a single-line paragraph begins with text identical to an enumerator (“A.”, “1.”, “(b)”, “I)”, etc.), the
first character will have to be escaped in order to have the line parsed as an ordinary paragraph:

\A. Einstein was a really smart dude.

Examples of nested enumerated lists:

1. Item 1 initial text.

   a) Item 1a.
   b) Item 1b.

2. a) Item 2a.
   b) Item 2b.

Example syntax diagram:

+-------+----------------------+
| "1. " | list item            |
+-------| (body elements)+     |
        +----------------------+

Definition Lists

Doctree elements: definition_list, definition_list_item, term, classifier, definition.

Each definition list item contains a term, optional classifiers, and a definition. A term is a simple
one-line word or phrase. Optional classifiers may follow the term on the same line, each after an inline ” :
” (space, colon, space). A definition is a block indented relative to the term, and may contain multiple
paragraphs and other body elements. There may be no blank line between a term line and a definition block
(this distinguishes definition lists from block
quotes). Blank lines are required before the first and after the last definition list item, but are
optional in-between. For example:

term 1
    Definition 1.

term 2
    Definition 2, paragraph 1.

    Definition 2, paragraph 2.

term 3 : classifier
    Definition 3.

term 4 : classifier one : classifier two
    Definition 4.

Inline markup is parsed in the term line before the classifier delimiter (” : “) is recognized. The
delimiter will only be recognized if it appears outside of any inline markup.

A definition list may be used in various ways, including:

• As a dictionary or glossary. The term is the word itself, a classifier may be used to indicate the
  usage of the term (noun, verb, etc.), and the definition follows.
• To describe program variables. The term is the variable name, a classifier may be used to indicate
  the type of the variable (string, integer, etc.), and the definition describes the variable’s use in
  the program. This usage of definition lists supports the classifier syntax of Grouch,
  a system for describing and enforcing a Python object schema.

Syntax diagram:

+----------------------------+
| term [ " : " classifier ]* |
+--+-------------------------+--+
   | definition                 |
   | (body elements)+           |
   +----------------------------+

Field Lists

Doctree elements: field_list, field, field_name, field_body.

Field lists are used as part of an extension syntax, such as options for directives,
or database-like records meant for further processing. They may also be used for two-column table-like
structures resembling database records (label & data pairs). Applications of reStructuredText may
recognize field names and transform fields or field bodies in certain contexts. For examples, see Bibliographic Fields below, or the “image“
and “meta“
directives in reStructuredText
Directives.

interpreted text with explicit roles in field names: the role must be a
suffix to the interpreted text. Field names are case-insensitive when further processed or transformed.
The field name, along with a single colon prefix and suffix, together form the field marker. The field
marker is followed by whitespace and the field body. The field body may contain multiple body elements,
indented relative to the field marker. The first line after the field name marker determines the
indentation of the field body. For example:

:Date: 2001-08-16
:Version: 1
:Authors: - Me
          - Myself
          - I
:Indentation: Since the field marker may be quite long, the second
   and subsequent lines of the field body do not have to line up
   with the first line, but they must be indented relative to the
   field name marker, and they must line up with each other.
:Parameter i: integer

The interpretation of individual words in a multi-word field name is up to the application. The application
may specify a syntax for the field name. For example, second and subsequent words may be treated as
“arguments”, quoted phrases may be treated as a single argument, and direct support for the “name=value”
syntax may be added.

Standard RFC822 headers
cannot be used for this construct because they are ambiguous. A word followed by a colon at the beginning of
a line is common in written text. However, in well-defined contexts such as when a field list invariably
occurs at the beginning of a document (PEPs and email messages), standard RFC822 headers could be used.

Syntax diagram (simplified):

+--------------------+----------------------+
| ":" field name ":" | field body           |
+-------+------------+                      |
        | (body elements)+                  |
        +-----------------------------------+

:Status: $keyword: expansion text $

Option Lists

Doctree elements: option_list, option_list_item, option_group, option, option_string, option_argument,
description.

Option lists are two-column lists of command-line options and descriptions, documenting a program’s options.
For example:

-a         Output all.
-b         Output both (this description is
           quite long).
-c arg     Output just arg.
--long     Output all day long.

-p         This option has two paragraphs in the description.
           This is the first.

           This is the second.  Blank lines may be omitted between
           options (as above) or left in (as here and below).

--very-long-option  A VMS-style option.  Note the adjustment for
                    the required two spaces.

--an-even-longer-option
           The description can also start on the next line.

-2, --two  This option has two variants.

-f FILE, --file=FILE  These two options are synonyms; both have
                      arguments.

/V         A VMS/DOS-style option.

There are several types of options recognized by reStructuredText:

• Short POSIX options consist of one dash and an option letter.
• Long POSIX options consist of two dashes and an option word; some systems use a single dash.
• Old GNU-style “plus” options consist of one plus and an option letter (“plus” options are deprecated
  now, their use discouraged).
• DOS/VMS options consist of a slash and an option letter or word.

Please note that both POSIX-style and DOS/VMS-style options may be used by DOS or Windows software. These
and other variations are sometimes used mixed together. The names above have been chosen for convenience
only.

The syntax for short and long POSIX options is based on the syntax supported by Python’s getopt.py module,
which implements an option parser similar to the GNU
libc getopt_long() function but with some restrictions. There are many variant option systems, and
reStructuredText option lists do not support all of them.

Although long POSIX and DOS/VMS option words may be allowed to be truncated by the operating system or the
application when used on the command line, reStructuredText option lists do not show or support this with
any special syntax. The complete option word should be given, supported by notes about truncation if and
when applicable.

Options may be followed by an argument placeholder, whose role and syntax should be explained in the
description text. Either a space or an equals sign may be used as a delimiter between options and option
argument placeholders; short options (“-” or “+” prefix only) may omit the delimiter. Option arguments may
take one of two forms:

• Begins with a letter ([a-zA-Z]) and
  subsequently consists of letters, numbers, underscores and hyphens ([a-zA-Z0-9_-]).
• Begins with an open-angle-bracket (<) and ends with a
  close-angle-bracket (>); any characters except angle brackets
  are allowed internally.

Multiple option “synonyms” may be listed, sharing a single description. They must be separated by
comma-space.

There must be at least two spaces between the option(s) and the description. The description may contain
multiple body elements. The first line after the option marker determines the indentation of the
description. As with other types of lists, blank lines are required before the first option list item and
after the last, but are optional between option entries.

Syntax diagram (simplified):

+----------------------------+-------------+
| option [" " argument] "  " | description |
+-------+--------------------+             |
        | (body elements)+                 |
        +----------------------------------+

Literal Blocks

Doctree element: literal_block.

A paragraph consisting of two colons (“::”) signifies that the following text block(s) comprise a literal
block. The literal block must either be indented or quoted (see below). No markup processing is done within
a literal block. It is left as-is, and is typically rendered in a monospaced typeface:

This is a typical paragraph.  An indented 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

This text has returned to the indentation of the first paragraph,
is outside of the literal block, and is therefore treated as an
ordinary paragraph.

The paragraph containing only “::” will be completely removed from the output; no empty paragraph will
remain.

As a convenience, the “::” is recognized at the end of any paragraph. If immediately preceded by whitespace,
both colons will be removed from the output (this is the “partially minimized” form). When text immediately
precedes the “::”, one colon will be removed from the output, leaving only one colon visible (i.e.,
“::” will be replaced by “:”; this is the “fully minimized” form).

In other words, these are all equivalent (please pay attention to the colons after “Paragraph”):

1. Expanded form:

   Paragraph:
   
   ::
   
       Literal block
   

2. Partially minimized form:

   Paragraph: ::
   
       Literal block
   

3. Fully minimized form:

   Paragraph::
   
       Literal block
   

All whitespace (including line breaks, but excluding minimum indentation for indented literal blocks) is
preserved. Blank lines are required before and after a literal block, but these blank lines are not included
as part of the literal block.

+------------------------------+
| paragraph                    |
| (ends with "::")             |
+------------------------------+
   +---------------------------+
   | indented literal block    |
   +---------------------------+

! " # $ % & ' ( ) * + , - . / : ; < = > ? @ [ \ ] ^ _ ` { | } ~

John Doe wrote::

>> Great idea!
>
> Why didn't I think of that?

You just did!  ;-)

+------------------------------+
| paragraph                    |
| (ends with "::")             |
+------------------------------+
+------------------------------+
| ">" per-line-quoted          |
| ">" contiguous literal block |
+------------------------------+

Line Blocks

Doctree elements: line_block, line. (New in Docutils 0.3.5.)

Line blocks are useful for address blocks, verse (poetry, song lyrics), and unadorned lists, where the
structure of lines is significant. Line blocks are groups of lines beginning with vertical bar (“|”)
prefixes. Each vertical bar prefix indicates a new line, so line breaks are preserved. Initial indents are
also significant, resulting in a nested structure. Inline markup is supported. Continuation lines are
wrapped portions of long lines; they begin with a space in place of the vertical bar. The left edge of a
continuation line must be indented, but need not be aligned with the left edge of the text above it. A line
block ends with a blank line.

This example illustrates continuation lines:

| Lend us a couple of bob till Thursday.
| I'm absolutely skint.
| But I'm expecting a postal order and I can pay you back
  as soon as it comes.
| Love, Ewan.

This example illustrates the nesting of line blocks, indicated by the initial indentation of new lines:

Take it away, Eric the Orchestra Leader!

    | A one, two, a one two three four
    |
    | Half a bee, philosophically,
    |     must, *ipso facto*, half not be.
    | But half the bee has got to be,
    |     *vis a vis* its entity.  D'you see?
    |
    | But can a bee be said to be
    |     or not to be an entire bee,
    |         when half the bee is not a bee,
    |             due to some ancient injury?
    |
    | Singing...

Syntax diagram:

+------+-----------------------+
| "| " | line                  |
+------| continuation line     |
       +-----------------------+

Block Quotes

Doctree element: block_quote, attribution.

A text block that is indented relative to the preceding text, without preceding markup indicating it to be a
literal block or other content, is a block quote. All markup processing (for body elements and inline
markup) continues within the block quote:

This is an ordinary paragraph, introducing a block quote.

    "It is my business to know things.  That is my trade."

    -- Sherlock Holmes

A block quote may end with an attribution: a text block beginning with “–“, “—“, or a true em-dash, flush
left within the block quote. If the attribution consists of multiple lines, the left edges of the second and
subsequent lines must align.

Multiple block quotes may occur consecutively if terminated with attributions.

Unindented paragraph.

Block quote 1.
—Attribution 1

Block quote 2.

Empty comments may be used to explicitly terminate
preceding constructs that would otherwise consume a block quote:

* List item.

..

    Block quote 3.

Empty comments may also be used to separate block quotes:

    Block quote 4.

..

    Block quote 5.

Blank lines are required before and after a block quote, but these blank lines are not included as part of
the block quote.

Syntax diagram:

+------------------------------+
| (current level of            |
| indentation)                 |
+------------------------------+
   +---------------------------+
   | block quote               |
   | (body elements)+          |
   |                           |
   | -- attribution text       |
   |    (optional)             |
   +---------------------------+

Doctest Blocks

Doctree element: doctest_block.

Doctest blocks are interactive Python sessions cut-and-pasted into docstrings. They are meant to illustrate
usage by example, and provide an elegant and powerful testing environment via the doctest
module in the Python standard library.

Doctest blocks are text blocks which begin with ">>> ", the Python interactive interpreter main prompt, and end with a
blank line. Doctest blocks are treated as a special case of literal blocks, without requiring the literal
block syntax. If both are present, the literal block syntax takes priority over Doctest block syntax:

This is an ordinary paragraph.

>>> print 'this is a Doctest block'
this is a Doctest block

The following is a literal block::

    >>> This is not recognized as a doctest block by
    reStructuredText.  It *will* be recognized by the doctest
    module, though!

Indentation is not required for doctest blocks.

Tables

Doctree elements: table, tgroup, colspec, thead, tbody, row, entry.

ReStructuredText provides two syntaxes for delineating table cells: Grid Tables and Simple Tables.

As with other body elements, blank lines are required before and after tables. Tables’ left edges should
align with the left edge of preceding text blocks; if indented, the table is considered to be part of a
block quote.

Once isolated, each table cell is treated as a miniature document; the top and bottom cell boundaries act as
delimiting blank lines. Each cell contains zero or more body elements. Cell contents may include left and/or
right margins, which are removed before processing.

+------------------------+------------+----------+----------+
| Header row, column 1   | Header 2   | Header 3 | Header 4 |
| (header rows optional) |            |          |          |
+========================+============+==========+==========+
| body row 1, column 1   | column 2   | column 3 | column 4 |
+------------------------+------------+----------+----------+
| body row 2             | Cells may span columns.          |
+------------------------+------------+---------------------+
| body row 3             | Cells may  | - Table cells       |
+------------------------+ span rows. | - contain           |
| body row 4             |            | - body elements.    |
+------------------------+------------+---------------------+

+--------------+----------+-----------+-----------+
| row 1, col 1 | column 2 | column 3  | column 4  |
+--------------+----------+-----------+-----------+
| row 2        |                                  |
+--------------+----------+-----------+-----------+
| row 3        |          |           |           |
+--------------+----------+-----------+-----------+

+--------------+----------+-----------+-----------+
| row 1, col 1 | column 2 | column 3  | column 4  |
+--------------+----------+-----------+-----------+
| row 2        | Use the command ``ls | more``.   |
+--------------+----------+-----------+-----------+
| row 3        |          |           |           |
+--------------+----------+-----------+-----------+

+--------------+----------+-----------+-----------+
| row 1, col 1 | column 2 | column 3  | column 4  |
+--------------+----------+-----------+-----------+
| row 2        |  Use the command ``ls | more``.  |
+--------------+----------+-----------+-----------+
| row 3        |          |           |           |
+--------------+----------+-----------+-----------+

+--------------+----------+-----------+-----------+
| row 1, col 1 | column 2 | column 3  | column 4  |
+--------------+----------+-----------+-----------+
| row 2        | Use the command ``ls | more``.   |
|              |                                  |
+--------------+----------+-----------+-----------+
| row 3        |          |           |           |
+--------------+----------+-----------+-----------+

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

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

=====  =====
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).
\      Row 4; column 1 will be empty.
=====  =====

Explicit Markup Blocks

An explicit markup block is a text block:

• whose first line begins with “..” followed by whitespace (the “explicit markup start”),
• whose second and subsequent lines (if any) are indented relative to the first, and
• which ends before an unindented line.

Explicit markup blocks are analogous to bullet list items, with “..” as the bullet. The text on the lines
immediately after the explicit markup start determines the indentation of the block body. The maximum common
indentation is always removed from the second and subsequent lines of the block body. Therefore if the first
construct fits in one line, and the indentation of the first and second constructs should differ, the first
construct should not begin on the same line as the explicit markup start.

Blank lines are required between explicit markup blocks and other elements, but are optional between
explicit markup blocks where unambiguous.

The explicit markup syntax is used for footnotes, citations, hyperlink targets, directives, substitution
definitions, and comments.

.. [1] Body elements go here.

+-------+-------------------------+
| ".. " | "[" label "]" footnote  |
+-------+                         |
        | (body elements)+        |
        +-------------------------+

[#]_ is a reference to footnote 1, and [#]_ is a reference to
footnote 2.

.. [#] This is footnote 1.
.. [#] This is footnote 2.
.. [#] This is footnote 3.

[#]_ is a reference to footnote 3.

Here is a symbolic footnote reference: [*]_.

.. [*] This is the footnote.

[2]_ will be "2" (manually numbered),
[#]_ will be "3" (anonymous auto-numbered), and
[#label]_ will be "1" (labeled auto-numbered).

.. [2] This footnote is labeled manually, so its number is fixed.

.. [#label] This autonumber-labeled footnote will be labeled "1".
   It is the first auto-numbered footnote and no other footnote
   with label "1" exists.  The order of the footnotes is used to
   determine numbering, not the order of the footnote references.

.. [#] This footnote will be labeled "3".  It is the second
   auto-numbered footnote, but footnote label "2" is already used.

Here is a citation reference: [CIT2002]_.

.. [CIT2002] This is the citation.  It's just like a footnote,
   except the label is textual.

.. _hyperlink-name: link-block

.. __: anonymous-hyperlink-target-link-block

__ anonymous-hyperlink-target-link-block

+-------+----------------------+
| ".. " | "_" name ":" link    |
+-------+ block                |
        |                      |
        +----------------------+

See `the web site of my favorite programming language`__.

.. __: http://www.python.org

__ http://www.python.org

.. image:: mylogo.jpeg

.. figure:: larch.png

   The larch.

.. note:: This is a paragraph

   - Here is a bullet list.

.. figure:: larch.png
   :scale: 50

   The larch.

+-------+-------------------------------+
| ".. " | directive type "::" directive |
+-------+ block                         |
        |                               |
        +-------------------------------+

The |biohazard| symbol must be used on containers used to
dispose of medical waste.

.. |biohazard| image:: biohazard.png

+-------+-----------------------------------------------------+
| ".. " | "|" substitution text "| " directive type "::" data |
+-------+ directive block                                     |
        |                                                     |
        +-----------------------------------------------------+

.. This is a comment
..
   _so: is this!
..
   [and] this!
..
   this:: too!
..
   |even| this:: !

+-------+----------------------+
| ".. " | comment              |
+-------+ block                |
        |                      |
        +----------------------+

Inline markup recognition rules

Inline markup start-strings and end-strings are only recognized if the following conditions are met:

1. Inline markup start-strings must be immediately followed by non-whitespace.
2. Inline markup end-strings must be immediately preceded by non-whitespace.
3. The inline markup end-string must be separated by at least one character from the start-string.
4. Both, inline markup start-string and end-string must not be preceded by an unescaped backslash
   (except for the end-string of inline
   literals). See Escaping
   Mechanism above for details.
5. If an inline markup start-string is immediately preceded by one of the ASCII characters ‘ ” < ( [ { or a similar non-ASCII character quotation marks in
   international usage.)

If the configuration setting simple-inline-markup is
False (default), additional conditions apply to the characters “around” the inline markup:

6. Inline markup start-strings must start a text block or be immediately preceded by
   • whitespace,
   • one of the ASCII characters - : / ' " < ( [ {
   • or a similar non-ASCII punctuation character. [13]
7. Inline markup end-strings must end a text block or be immediately followed by
   • whitespace,
   • one of the ASCII characters - . , : ; ! ? \ / ' " ) ] }
     >
   • or a similar non-ASCII punctuation character. [14]

The inline markup recognition rules were devised to allow 90% of non-markup uses of “*”, “`”, “_”, and “|”
without escaping. For example, none of the following terms are recognized as containing inline markup
strings:

• 2 * x a ** b (* BOM32_* ` “ _ __ | (breaks rule 1)
• || (breaks rule 3)
• “*” ‘|’ (*) [*] {*} <*> ‘*’ ‚*‘ ‘*‚ ’*’ ‚*’ “*” „*“ “*„ ”*” „*” »*« ›*‹ «*» »*» ›*› (breaks
  rule 5)
• 2*x a**b O(N**2) e**(x*y) f(x)*f(y) a|b file*.* __init__ __init__() (breaks rule 6)

No escaping is required inside the following inline markup examples:

• *2 * x  *a **b *.txt* (breaks rule 2; renders as “2 * x *a **b
  *.txt“)
• *2*x a**b O(N**2) e**(x*y) f(x)*f(y) a*(1+2)* (breaks rule 7; renders as “2*x a**b O(N**2) e**(x*y)
  f(x)*f(y) a*(1+2)“)

It may be desirable to use inline literals for
some of these anyhow, especially if they represent code snippets. It’s a judgment call.

The following terms do require either literal-quoting or escaping to avoid misinterpretation:

*4, class_, *args, **kwargs, `TeX-quoted', *ML, *.txt

In most use cases, inline literals or literal blocks are the best choice (by default,
this also selects a monospaced font). Alternatively, the inline markup characters can be escaped:

\*4, class\_, \*args, \**kwargs, \`TeX-quoted', \*ML, \*.txt

For languages that don’t use whitespace between words (e.g. Japanese or Chinese) it is recommended to set simple-inline-markup to
True and eventually escape inline markup characters. The examples breaking rules 6 and 7 above show which
constructs may need special attention.

Recognition order

Inline markup delimiter characters are used for multiple constructs, so to avoid ambiguity there must be a
specific recognition order for each character. The inline markup recognition order is as follows:

• Asterisks: Strong emphasis (“**”) is
  recognized before emphasis (“*”).
• Backquotes: Inline literals (““”), inline internal targets (leading
  “_`”, trailing “`”), are mutually independent, and are recognized before phrase hyperlink references (leading
  “`”, trailing “`_”) and interpreted text (“`”).
• Trailing underscores: Footnote references (“[” + label + “]_”) and simple hyperlink references (name +
  trailing “_”) are mutually independent.
• Vertical bars: Substitution
  references (“|”) are independently recognized.
• Standalone hyperlinks are the last
  to be recognized.

Character-Level Inline Markup

It is possible to mark up individual characters within a word with backslash escapes (see Escaping Mechanism above). Backslash escapes
can be used to allow arbitrary text to immediately follow inline markup:

Python ``list``\s use square bracket syntax.

The backslash will disappear from the processed document. The word “list” will appear as inline literal
text, and the letter “s” will immediately follow it as normal text, with no space in-between.

Arbitrary text may immediately precede inline markup using backslash-escaped whitespace:

Possible in *re*\ ``Structured``\ *Text*, though not encouraged.

The backslashes and spaces separating “re”, “Structured”, and “Text” above will disappear from the processed
document.

Emphasis

Doctree element: emphasis.

Start-string = end-string = “*”.

Text enclosed by single asterisk characters is emphasized:

This is *emphasized text*.

Emphasized text is typically displayed in italics.

Strong Emphasis

Doctree element: strong.

Start-string = end-string = “**”.

Text enclosed by double-asterisks is emphasized strongly:

This is **strong text**.

Strongly emphasized text is typically displayed in boldface.

Interpreted Text

Doctree element: depends on the explicit or implicit role and processing.

Start-string = end-string = “`”.

Interpreted text is text that is meant to be related, indexed, linked, summarized, or otherwise processed,
but the text itself is typically left alone. Interpreted text is enclosed by single backquote characters:

This is `interpreted text`.

The “role” of the interpreted text determines how the text is interpreted. The role may be inferred
implicitly (as above; the “default role” is used) or indicated explicitly, using a role marker. A role
marker consists of a colon, the role name, and another colon. A role name is a single word consisting of
alphanumerics plus isolated internal hyphens, underscores, plus signs, colons, and periods; no whitespace or
other characters are allowed. A role marker is either a prefix or a suffix to the interpreted text,
whichever reads better; it’s up to the author:

:role:`interpreted text`

`interpreted text`:role:

Interpreted text allows extensions to the available inline descriptive markup constructs. To emphasis, strong emphasis, inline literals, and hyperlink references, we can add “title
reference”, “index entry”, “acronym”, “class”, “red”, “blinking” or anything else we want. Only
pre-determined roles are recognized; unknown roles will generate errors. A core set of standard roles is
implemented in the reference parser; see reStructuredText
Interpreted Text Roles for individual descriptions. The role directive
can be used to define custom interpreted text roles. In addition, applications may support specialized
roles.

In field lists, care must be taken when using
interpreted text with explicit roles in field names: the role must be a suffix to the interpreted text. The
following are recognized as field list items:

:`field name`:code:: interpreted text with explicit role as suffix

:a `complex`:code:\  field name: a backslash-escaped space
                                 is necessary

The following are not recognized as field list items:

::code:`not a field name`: paragraph with interpreted text

:code:`not a field name`: paragraph with interpreted text

Edge cases:

:field\:`name`: interpreted text (standard role) requires
                escaping the leading colon in a field name

:field:\`name`: not interpreted text

Inline Literals

Doctree element: literal.

Start-string = end-string = ““”.

Text enclosed by double-backquotes is treated as inline literals:

This text is an example of ``inline literals``.

Inline literals may contain any characters except two adjacent backquotes in an end-string context
(according to the recognition rules above). No markup interpretation (including backslash-escape
interpretation) is done within inline literals.

Line breaks are not preserved in inline literals. Although a reStructuredText parser will preserve
runs of spaces in its output, the final representation of the processed document is dependent on the output
formatter, thus the preservation of whitespace cannot be guaranteed. If the preservation of line breaks
and/or other whitespace is important, literal
blocks should be used.

Inline literals are useful for short code snippets. For example:

The regular expression ``[+-]?(\d+(\.\d*)?|\.\d+)`` matches
floating-point numbers (without exponents).

Hyperlink References

Doctree element: reference.

• Named hyperlink references:
  • No start-string, end-string = “_”.
  • Start-string = “`”, end-string = “`_”. (Phrase references.)
• Anonymous hyperlink references:
  • No start-string, end-string = “__”.
  • Start-string = “`”, end-string = “`__”. (Phrase references.)

Hyperlink references are indicated by a trailing underscore, “_”, except for standalone
hyperlinks which are recognized independently. The underscore can be thought of as a right-pointing
arrow. The trailing underscores point away from hyperlink references, and the leading underscores point
toward hyperlink targets.

Hyperlinks consist of two parts. In the text body, there is a source link, a reference name with a trailing
underscore (or two underscores for anonymous
hyperlinks):

See the Python_ home page for info.

A target link with a matching reference name must exist somewhere else in the document. See Hyperlink Targets for a full description).

Anonymous hyperlinks (which see) do not use
reference names to match references to targets, but otherwise behave similarly to named hyperlinks.

See the `Python home page <http://www.python.org>`_ for info.

This `link <Python home page_>`_ is an alias to the link above.

See the `Python home page`_ for info.

This link_ is an alias to the link above.

.. _Python home page: http://www.python.org
.. _link: `Python home page`_

`RFC 2396 <http://www.rfc-editor.org/rfc/rfc2396.txt>`__ and `RFC
2732 <http://www.rfc-editor.org/rfc/rfc2732.txt>`__ together
define the syntax of URIs.

`RFC 2396`__ and `RFC 2732`__ together define the syntax of URIs.

__ http://www.rfc-editor.org/rfc/rfc2396.txt
__ http://www.rfc-editor.org/rfc/rfc2732.txt

`__init__ <http:example.py.html#__init__>`__

Use the `source <parrots.txt\_>`__.

See `HTML Element: \<a>`_, `HTML Element: <b\> `_, and
`HTML Element: <c>\ `_.

See `<a_named_relative_link>`_ or `<an_anonymous_relative_link>`__
for details.

Inline Internal Targets

Doctree element: target.

Start-string = “_`”, end-string = “`”.

Inline internal targets are the equivalent of explicit internal
hyperlink targets, but may appear within running text. The syntax begins with an underscore and a
backquote, is followed by a hyperlink name or phrase, and ends with a backquote. Inline internal targets may
not be anonymous.

For example, the following paragraph contains a hyperlink target named “Norwegian Blue”:

Oh yes, the _`Norwegian Blue`.  What's, um, what's wrong with it?

See Implicit Hyperlink Targets for the
resolution of duplicate reference names.

Footnote References

See also: Footnotes

Doctree element: footnote_reference.

Configuration settings: footnote_references, trim_footnote_reference_space.

Start-string = “[“, end-string = “]_”.

Each footnote reference consists of a square-bracketed label followed by a trailing underscore. Footnote
labels are one of:

• one or more digits (i.e., a number),
• a single “#” (denoting auto-numbered
  footnotes),
• a “#” followed by a simple reference name (an autonumber label), or
• a single “*” (denoting auto-symbol
  footnotes).

For example:

Please RTFM [1]_.

.. [1] Read The Fine Manual

Inline markup recognition rules may
require whitespace in front of the footnote reference. To remove the whitespace from the output, use an
escaped whitespace character (see Escaping
Mechanism) or set the trim_footnote_reference_space configuration
setting. Leading whitespace is removed by default, if the footnote_references
setting is “superscript”.

Citation References

See also: Citations

Doctree element: citation_reference.

Start-string = “[“, end-string = “]_”.

Each citation reference consists of a square-bracketed label followed by a trailing underscore. Citation
labels are simple reference names (case-insensitive
single words, consisting of alphanumerics plus internal hyphens, underscores, and periods; no whitespace).

For example:

Here is a citation reference: [CIT2002]_.

Substitution References

Doctree element: substitution_reference, reference.

Start-string = “|”, end-string = “|” (optionally followed by “_” or “__”).

Vertical bars are used to bracket the substitution reference text. A substitution reference may also be a
hyperlink reference by appending a “_” (named) or “__” (anonymous) suffix; the substitution text is used for
the reference text in the named case.

The processing system replaces substitution references with the processed contents of the corresponding substitution definitions (which see for
the definition of “correspond”). Substitution definitions produce inline-compatible elements.

Examples:

This is a simple |substitution reference|.  It will be replaced by
the processing system.

This is a combination |substitution and hyperlink reference|_.  In
addition to being replaced, the replacement text or element will
refer to the "substitution and hyperlink reference" target.

Standalone Hyperlinks

Doctree element: reference.

No start-string or end-string.

A URI (absolute URI [16] or standalone email address) within a text block is treated as a
general external hyperlink with the URI itself as the link’s text. For example:

See http://www.python.org for info.

would be marked up in HTML as:

See <a href="http://www.python.org">http://www.python.org</a> for
info.

Two forms of URI are recognized:

1. Absolute URIs. These consist of a scheme, a colon (“:”), and a scheme-specific part
   whose interpretation depends on the scheme.
   The scheme is the name of the protocol, such as “http”, “ftp”, “mailto”, or “telnet”. The scheme
   consists of an initial letter, followed by letters, numbers, and/or “+”, “-“, “.”. Recognition is
   limited to known schemes, per the Official
   IANA Registry of URI Schemes and the W3C’s Retired
   Index of WWW Addressing Schemes.

   The scheme-specific part of the resource identifier may be either hierarchical or opaque:

   • Hierarchical identifiers begin with one or two slashes and may use slashes
     to separate hierarchical components of the path. Examples are web pages and FTP
     sites:

     http://www.python.org
     
     ftp://ftp.python.org/pub/python
     

   • Opaque identifiers do not begin with slashes. Examples are email addresses
     and newsgroups:

     mailto:someone@somewhere.com
     
     news:comp.lang.python
     

   With queries, fragments, and %-escape sequences, URIs can become quite complicated. A
   reStructuredText parser must be able to recognize any absolute URI, as defined in RFC2396 and RFC2732.

2. Standalone email addresses, which are treated as if they were absolute URIs with a
   “mailto:” scheme. Example:

   someone@somewhere.com
   

Punctuation at the end of a URI is not considered part of the URI, unless the URI is terminated by a closing
angle bracket (“>”). Backslashes may be used in URIs to escape markup characters, specifically asterisks
(“*”) and underscores (“_”) which are vaid URI characters (see Escaping
Mechanism above).

Length Units

The following length units are supported by the reStructuredText parser:

• em (ems, the height of the element’s font)
• ex (x-height, the height of the letter “x”)
• px (pixels, relative to the canvas resolution)
• in (inches; 1in=2.54cm)
• cm (centimeters; 1cm=10mm)
• mm (millimeters)
• pt (points; 1pt=1/72in)
• pc (picas; 1pc=12pt)

This set corresponds to the length units in
CSS.

(List and explanations taken from http://www.htmlhelp.com/reference/css/units.html#length.)

The following are all valid length values: “1.5em”, “20 mm”, “.5in”.

Length values without unit are completed with a writer-dependent default (e.g. px
with html4css1, pt with latex2e). See the writer specific documentation in the user doc for details.

Percentage Units

Percentage values have a percent sign (“%”) as unit. Percentage values are relative to other values,
depending on the context in which they occur.