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reStructuredText markup

This document describes the custom reStructuredText markup introduced by Sphinx to support Python documentation and how it should be used.

Quick reference

This table summarizes which markup should be used for some commonly used elements:

Element Markup See also
arguments/parameters *arg* :ref:`inline-markup`
variables/literals/code ``foo``, ``42``, ``len(s) - 1`` :ref:`inline-markup`
True/False/None ``True``, ``False``, ``None`` :ref:`inline-markup`
function definitions .. function:: print(*args) :ref:`directives`
function references :func:`print` :ref:`roles`
attribute definitions .. attribute: `attr-name` :ref:`information-units`
attribute references :attr:`attr-name` :ref:`roles`
reference labels .. _label-name: :ref:`doc-ref-role`
internal references :ref:`label-name` :ref:`doc-ref-role`
external links `Link text <https://example.com>`_ :ref:`hyperlinks`
roles w/ custom text :role:`custom text <target>` :ref:`roles`
roles w/ only last part :role:`~hidden.hidden.visible` :ref:`roles`
roles w/o link :role:`!target` :ref:`roles`
issues :gh:`ID`, :issue:`ID` :ref:`roles`
CPython source :source:`PATH` :ref:`roles`
comments .. a comment :ref:`comments`

reStructuredText primer

This section is a brief introduction to reStructuredText (reST) concepts and syntax, intended to provide authors with enough information to author documents productively. Since reST was designed to be a simple, unobtrusive markup language, this will not take too long.

.. seealso::

    The authoritative `reStructuredText User
    Documentation <https://docutils.sourceforge.io/rst.html>`_.

Use of whitespace

All reST files use an indentation of 3 spaces; no tabs are allowed. The maximum line length is 80 characters for normal text, but tables, deeply indented code samples and long links may extend beyond that. Code example bodies should use normal Python 4-space indentation.

Make use of multiple blank lines where applicable to clarify the structure of the reST file. Extra blank lines help group sections together to make the organization of the file clearer.

A sentence-ending period may be followed by one or two spaces. While reST ignores the second space, it is customarily put in by some users, for example to aid Emacs' auto-fill mode.

Paragraphs

The paragraph is the most basic block in a reST document. Paragraphs are simply chunks of text separated by one or more blank lines. As in Python, indentation is significant in reST, so all lines of the same paragraph must be left-aligned to the same level of indentation.

Inline markup

The standard reST inline markup is quite simple: use

  • one asterisk: *text* for emphasis (italics),
  • two asterisks: **text** for strong emphasis (boldface), and
  • backquotes: ``text`` for code samples, variables, and literals.

If asterisks or backquotes appear in running text and could be confused with inline markup delimiters, they have to be escaped with a backslash.

Be aware of some restrictions of this markup:

  • it may not be nested,
  • content may not start or end with whitespace: * text* is wrong,
  • it must be separated from surrounding text by non-word characters. Use a backslash escaped space to work around that: thisis\ *one*\ word.

These restrictions may be lifted in future versions of the docutils.

reST also allows for custom "interpreted text roles", which signify that the enclosed text should be interpreted in a specific way. Sphinx uses this to provide semantic markup and cross-referencing of identifiers, as described in the appropriate section. The general syntax is :rolename:`content`.

Lists and quotes

List markup is natural: just place an asterisk at the start of a paragraph and indent properly. The same goes for numbered lists; they can also be automatically numbered using a # sign:

* This is a bulleted list.
* It has two items, the second
  item uses two lines.

1. This is a numbered list.
2. It has two items too.

#. This is a numbered list.
#. It has two items too.

Nested lists are possible, but be aware that they must be separated from the parent list items by blank lines:

* this is
* a list

  * with a nested list
  * and some subitems

* and here the parent list continues

Definition lists are created as follows:

term (up to a line of text)
   Definition of the term, which must be indented

   and can even consist of multiple paragraphs

next term
   Description.

Paragraphs are quoted by just indenting them more than the surrounding paragraphs.

Source code

Literal code blocks are introduced by ending a paragraph with the special marker ::. The literal block must be indented:

This is a normal text paragraph. The next paragraph is a code sample::

   It is not processed in any way, except
   that the indentation is removed.

   It can span multiple lines.

This is a normal text paragraph again.

The handling of the :: marker is smart:

  • If it occurs as a paragraph of its own, that paragraph is completely left out of the document.
  • If it is preceded by whitespace, the marker is removed.
  • If it is preceded by non-whitespace, the marker is replaced by a single colon.

That way, the second sentence in the above example's first paragraph would be rendered as "The next paragraph is a code sample:".

Hyperlinks

External links

Use `Link text <http://target>`_ for inline web links. If the link text should be the web address, you don't need special markup at all, the parser finds links and mail addresses in ordinary text.

Internal links

Internal linking is done via a special reST role, see the section on specific markup, :ref:`doc-ref-role`.

Sections

Section headers are created by underlining (and optionally overlining) the section title with a punctuation character, at least as long as the text:

=================
This is a heading
=================

Normally, there are no heading levels assigned to certain characters as the structure is determined from the succession of headings. However, for the Python documentation, here is a suggested convention:

  • # with overline, for parts
  • * with overline, for chapters
  • =, for sections
  • -, for subsections
  • ^, for subsubsections
  • ", for paragraphs

Explicit markup

"Explicit markup" is used in reST for most constructs that need special handling, such as footnotes, specially-highlighted paragraphs, comments, and generic directives.

An explicit markup block begins with a line starting with .. followed by whitespace and is terminated by the next paragraph at the same level of indentation. (There needs to be a blank line between explicit markup and normal paragraphs. This may all sound a bit complicated, but it is intuitive enough when you write it.)

Directives

A directive is a generic block of explicit markup. Besides roles, it is one of the extension mechanisms of reST, and Sphinx makes heavy use of it.

Basically, a directive consists of a name, arguments, options and content. (Keep this terminology in mind, it is used in :ref:`the next section <additional-markup-constructs>` describing custom directives.) Looking at this example,

.. function:: foo(x)
              foo(y, z)
   :bar: no

   Return a line of text input from the user.

function is the directive name. It is given two arguments here, the remainder of the first line and the second line, as well as one option bar (as you can see, options are given in the lines immediately following the arguments and indicated by the colons).

The directive content follows after a blank line and is indented relative to the directive start.

Footnotes

For footnotes, use [#]_ to mark the footnote location, and add the footnote body at the bottom of the document after a "Footnotes" rubric heading, like so:

Lorem ipsum [#]_ dolor sit amet ... [#]_

.. rubric:: Footnotes

.. [#] Text of the first footnote.
.. [#] Text of the second footnote.

You can also explicitly number the footnotes for better context.

Comments

Every explicit markup block (starting with .. ) which isn't a :ref:`valid markup construct <directives>` is regarded as a comment:

.. This is a comment

Source encoding

Since the easiest way to include special characters like em dashes or copyright signs in reST is to directly write them as Unicode characters, one has to specify an encoding:

All Python documentation source files must be in UTF-8 encoding, and the HTML documents written from them will be in that encoding as well.

Gotchas

There are some problems one commonly runs into while authoring reST documents:

  • Separation of inline markup: As said above, inline markup spans must be separated from the surrounding text by non-word characters, you have to use an escaped space to get around that.

Typographic conventions

Big O notation

Big O notation is used to describe the performance of algorithms.

Use italics for the big O and variables. For example:

reStructuredText Rendered
*O*\ (1) O(1)
*O*\ (log *n*) O(log n)
*O*\ (*n*) O(n)
*O*\ (*n* log *n*) O(n log n)
*O*\ (*n*\ :sup:`2`) O(n2)

Additional markup constructs

Sphinx adds a lot of new directives and interpreted text roles to standard reST markup. This section contains the reference material for these facilities. Documentation for "standard" reST constructs is not included here, though they are used in the Python documentation.

Note

This is just an overview of Sphinx' extended markup capabilities; full coverage can be found in its own documentation.

Meta-information markup

.. describe:: sectionauthor

   Identifies the author of the current section.  The argument should include
   the author's name such that it can be used for presentation (though it isn't)
   and email address.  The domain name portion of the address should be lower
   case.  Example::

      .. sectionauthor:: Guido van Rossum <[email protected]>

   Currently, this markup isn't reflected in the output in any way, but it helps
   keep track of contributions.

Module-specific markup

The markup described in this section is used to provide information about a module being documented. Each module should be documented in its own file. Normally this markup appears after the title heading of that file; a typical file might start like this:

:mod:`parrot` -- Dead parrot access
===================================

.. module:: parrot
   :platform: Unix, Windows
   :synopsis: Analyze and reanimate dead parrots.
.. moduleauthor:: Eric Cleese <[email protected]>
.. moduleauthor:: John Idle <[email protected]>

As you can see, the module-specific markup consists of two directives, the module directive and the moduleauthor directive.

.. describe:: module

   This directive marks the beginning of the description of a module, package,
   or submodule. The name should be fully qualified (that is, including the
   package name for submodules).

   The ``platform`` option, if present, is a comma-separated list of the
   platforms on which the module is available (if it is available on all
   platforms, the option should be omitted).  The keys are short identifiers;
   examples that are in use include "IRIX", "Mac", "Windows", and "Unix".  It is
   important to use a key which has already been used when applicable.

   The ``synopsis`` option should consist of one sentence describing the
   module's purpose -- it is currently only used in the Global Module Index.

   The ``deprecated`` option can be given (with no value) to mark a module as
   deprecated; it will be designated as such in various locations then.

.. describe:: moduleauthor

   The ``moduleauthor`` directive, which can appear multiple times, names the
   authors of the module code, just like ``sectionauthor`` names the author(s)
   of a piece of documentation.  It too does not result in any output currently.

Note

It is important to make the section title of a module-describing file meaningful since that value will be inserted in the table-of-contents trees in overview files.

Information units

There are a number of directives used to describe specific features provided by modules. Each directive requires one or more signatures to provide basic information about what is being described, and the content should be the description. The basic version makes entries in the general index; if no index entry is desired, you can give the directive option flag :noindex:. The following example shows all of the features of this directive type:

.. function:: spam(eggs)
              ham(eggs)
   :noindex:

   Spam or ham the foo.

The signatures of object methods or data attributes should not include the class name, but be nested in a class directive. The generated files will reflect this nesting, and the target identifiers (for HTML output) will use both the class and method name, to enable consistent cross-references. If you describe methods belonging to an abstract protocol such as context managers, use a class directive with a (pseudo-)type name too to make the index entries more informative.

The directives are:

.. describe:: c:function

   Describes a C function. The signature should be given as in C, for example::

      .. c:function:: PyObject* PyType_GenericAlloc(PyTypeObject *type, Py_ssize_t nitems)

   This is also used to describe function-like preprocessor macros.  The names
   of the arguments should be given so they may be used in the description.

   Note that you don't have to backslash-escape asterisks in the signature,
   as it is not parsed by the reST inliner.

.. describe:: c:member

   Describes a C struct member. Example signature::

      .. c:member:: PyObject* PyTypeObject.tp_bases

   The text of the description should include the range of values allowed, how
   the value should be interpreted, and whether the value can be changed.
   References to structure members in text should use the ``member`` role.

.. describe:: c:macro

   Describes a "simple" C macro.  Simple macros are macros which are used
   for code expansion, but which do not take arguments so cannot be described as
   functions.  This is not to be used for simple constant definitions.  Examples
   of its use in the Python documentation include :c:macro:`PyObject_HEAD` and
   :c:macro:`Py_BEGIN_ALLOW_THREADS`.

.. describe:: c:type

   Describes a C type. The signature should just be the type name.

.. describe:: c:var

   Describes a global C variable.  The signature should include the type, such
   as::

      .. c:var:: PyObject* PyClass_Type

.. describe:: data

   Describes global data in a module, including both variables and values used
   as "defined constants."  Class and object attributes are not documented
   using this directive.

.. describe:: exception

   Describes an exception class.  The signature can, but need not include
   parentheses with constructor arguments.

.. describe:: function

   Describes a module-level function.  The signature should include the
   parameters, enclosing optional parameters in brackets.  Default values can be
   given if it enhances clarity.  For example::

      .. function:: repeat([repeat=3[, number=1000000]])

   Object methods are not documented using this directive. Bound object methods
   placed in the module namespace as part of the public interface of the module
   are documented using this, as they are equivalent to normal functions for
   most purposes.

   The description should include information about the parameters required and
   how they are used (especially whether mutable objects passed as parameters
   are modified), side effects, and possible exceptions.  A small example may be
   provided.

.. describe:: coroutinefunction

   Describes a module-level coroutine.  The description should include similar
   information to that described for ``function``.

.. describe:: decorator

   Describes a decorator function.  The signature should *not* represent the
   signature of the actual function, but the usage as a decorator.  For example,
   given the functions

   .. code-block:: python

      def removename(func):
          func.__name__ = ''
          return func

      def setnewname(name):
          def decorator(func):
              func.__name__ = name
              return func
          return decorator

   the descriptions should look like this::

      .. decorator:: removename

         Remove name of the decorated function.

      .. decorator:: setnewname(name)

         Set name of the decorated function to *name*.

   There is no ``deco`` role to link to a decorator that is marked up with
   this directive; rather, use the ``:func:`` role.

.. describe:: class

   Describes a class.  The signature can include parentheses with parameters
   which will be shown as the constructor arguments.

.. describe:: attribute

   Describes an object data attribute.  The description should include
   information about the type of the data to be expected and whether it may be
   changed directly.  This directive should be nested in a class directive,
   like in this example::

      .. class:: Spam

         Description of the class.

         .. attribute:: ham

            Description of the attribute.

   Refer to an attribute using the ``:attr:`` role::

      Use the :attr:`ham` attribute to spam the eggs.

   If is also possible to document an attribute outside of a class directive,
   for example if the documentation for different attributes and methods is
   split in multiple sections.  The class name should then be included
   explicitly::

      .. attribute:: Spam.eggs

.. describe:: method

   Describes an object method.  The parameters should not include the ``self``
   parameter.  The description should include similar information to that
   described for ``function``.  This directive should be nested in a class
   directive, like in the example above.

.. describe:: coroutinemethod

   Describes an object coroutine method.  The parameters should not include the
   ``self`` parameter.  The description should include similar information to
   that described for ``function``.  This directive should be nested in a
   ``class`` directive.

.. describe:: decoratormethod

   Same as ``decorator``, but for decorators that are methods.

   Refer to a decorator method using the ``:meth:`` role.

.. describe:: staticmethod

   Describes an object static method.  The description should include similar
   information to that described for ``function``.  This directive should be
   nested in a ``class`` directive.

.. describe:: classmethod

   Describes an object class method.  The parameters should not include the
   ``cls`` parameter.  The description should include similar information to
   that described for ``function``.  This directive should be nested in a
   ``class`` directive.

.. describe:: abstractmethod

   Describes an object abstract method.  The description should include similar
   information to that described for ``function``.  This directive should be
   nested in a ``class`` directive.

.. describe:: opcode

   Describes a Python :term:`bytecode` instruction.

.. describe:: option

   Describes a Python command line option or switch.  Option argument names
   should be enclosed in angle brackets.  Example::

      .. option:: -m <module>

         Run a module as a script.

.. describe:: envvar

   Describes an environment variable that Python uses or defines.

There is also a generic version of these directives:

.. describe:: describe

   This directive produces the same formatting as the specific ones explained
   above but does not create index entries or cross-referencing targets.  It is
   used, for example, to describe the directives in this document. Example::

      .. describe:: opcode

         Describes a Python bytecode instruction.

Showing code examples

Examples of Python source code or interactive sessions are represented using standard reST literal blocks. They are started by a :: at the end of the preceding paragraph and delimited by indentation.

Representing an interactive session requires including the prompts and output along with the Python code. No special markup is required for interactive sessions. After the last line of input or output is presented, there should be no trailing prompt. An example of correct usage is:

>>> 1 + 1
2

Syntax highlighting is handled in a smart way:

  • There is a "highlighting language" for each source file. By default, this is 'python' as the majority of files will have to highlight Python snippets.

  • Within Python highlighting mode, interactive sessions are recognized automatically and highlighted appropriately.

  • The highlighting language can be changed using the highlight directive, used as follows:

    .. highlight:: c

    This language is used until the next highlight directive is encountered.

  • The code-block directive can be used to specify the highlight language of a single code block, for example:

    .. code-block:: c

   #include <stdio.h>

   void main() {
       printf("Hello world!\n");
   }

  • The values normally used for the highlighting language are:

    • python (the default)
    • c
    • rest
    • none (no highlighting)

  • If highlighting with the current language fails, the block is not highlighted in any way.

Longer displays of verbatim text may be included by storing the example text in an external file containing only plain text. The file may be included using the literalinclude directive. For example, to include the Python source file :file:`example.py`, use:

.. literalinclude:: example.py

The file name is relative to the current file's path. Documentation-specific include files should be placed in the Doc/includes subdirectory.

Note

There is a standard include directive, but it raises errors if the file is not found. literalinclude is preferred because it only emits a warning instead of raising an error.

Roles

As :ref:`previously mentioned <inline-markup>`, Sphinx uses interpreted text roles of the form :rolename:`content` to insert semantic markup in documents.

In the CPython documentation, there are a couple common cases where simpler markup should be used:

  • *arg* (rendered as arg) for function and method arguments.
  • ``True``/``False``/``None`` for True/False/None.

In addition, the CPython documentation defines a few custom roles:

  • :cve:`YYYY-NNNNN`: link to a Common Vulnerabilities and Exposures entry.
  • :cwe:`NNN`: link to a Common Weakness Enumeration entry.
  • :gh:`ID`: link to a GitHub issue.
  • :issue:`ID`: link to a bugs.python.com issue.
  • :pypi:`NAME`: link to a project on PyPI.
  • :source:`PATH`: link to a source file on GitHub.

There are some additional facilities that make cross-referencing roles more versatile:

  • You may supply an explicit title and reference target, like in reST direct hyperlinks: :role:`title <target>` will refer to target, but the link text will be title.

  • If you prefix the content with !, no reference/hyperlink will be created.

  • For the Python object roles, if you prefix the content with ~, the link text will only be the last component of the target. For example, :meth:`~Queue.Queue.get` will refer to Queue.Queue.get but only display get as the link text.

    In HTML output, the link's title attribute (that might be shown as a tool-tip on mouse-hover) will always be the full target name.

  • Combining ~ and ! (for example, :meth:`~!Queue.Queue.get`) is not supported. You can obtain the same result by using ! and the last component of the target (for example, :meth:`!get`).

The following roles refer to objects in modules and are possibly hyperlinked if a matching identifier is found:

.. describe:: mod

   The name of a module; a dotted name may be used.  This should also be used
   for package names.

.. describe:: func

   The name of a Python function; dotted names may be used.  The role text
   should not include trailing parentheses to enhance readability.  The
   parentheses are stripped when searching for identifiers.

.. describe:: data

   The name of a module-level variable or constant.

.. describe:: const

   The name of a "defined" constant.  This may be a C-language ``#define``
   or a Python variable that is not intended to be changed.

.. describe:: class

   A class name; a dotted name may be used.

.. describe:: meth

   The name of a method of an object.  The role text should include the type
   name and the method name.  A dotted name may be used.

.. describe:: attr

   The name of a data attribute of an object.

.. describe:: exc

   The name of an exception. A dotted name may be used.

The name enclosed in this markup can include a module name and/or a class name. For example, :func:`filter` could refer to a function named filter in the current module, or the built-in function of that name. In contrast, :func:`foo.filter` clearly refers to the filter function in the foo module.

Normally, names in these roles are searched first without any further qualification, then with the current module name prepended, then with the current module and class name (if any) prepended. If you prefix the name with a dot, this order is reversed. For example, in the documentation of the :mod:`codecs` module, :func:`open` always refers to the built-in function, while :func:`.open` refers to :func:`codecs.open`.

A similar heuristic is used to determine whether the name is an attribute of the currently documented class.

The following roles create cross-references to C-language constructs if they are defined in the API documentation:

.. describe:: c:data

   The name of a C-language variable.

.. describe:: c:func

   The name of a C-language function. Should include trailing parentheses.

.. describe:: c:macro

   The name of a "simple" C macro, as defined above.

.. describe:: c:type

   The name of a C-language type.

.. describe:: c:member

   The name of a C type member, as defined above.

The following roles do not refer to objects, but can create cross-references or internal links:

.. describe:: envvar

   An environment variable.  Index entries are generated.

.. describe:: keyword

   The name of a Python keyword.  Using this role will generate a link to the
   documentation of the keyword.  ``True``, ``False`` and ``None`` do not use
   this role, but simple code markup (````True````), given that they're
   fundamental to the language and should be known to any programmer.

.. describe:: option

   A command-line option of Python.  The leading hyphen(s) must be included.
   If a matching ``cmdoption`` directive exists, it is linked to.  For options
   of other programs or scripts, use simple ````code```` markup.

.. describe:: token

   The name of a grammar token (used in the reference manual to create links
   between production displays).

The following role creates a cross-reference to the term in the glossary:

.. describe:: term

   Reference to a term in the glossary.  The glossary is created using the
   ``glossary`` directive containing a definition list with terms and
   definitions.  It does not have to be in the same file as the ``term``
   markup, in fact, by default the Python docs have one global glossary
   in the ``glossary.rst`` file.

   If you use a term that's not explained in a glossary, you'll get a warning
   during build.

The following roles don't do anything special except formatting the text in a different style:

.. describe:: command

   The name of an OS-level command, such as ``rm``.

.. describe:: dfn

   Mark the defining instance of a term in the text.  (No index entries are
   generated.)

.. describe:: file

   The name of a file or directory.  Within the contents, you can use curly
   braces to indicate a "variable" part, for example::

      ``spam`` is installed in :file:`/usr/lib/python2.{x}/site-packages` ...

   In the built documentation, the ``x`` will be displayed differently to
   indicate that it is to be replaced by the Python minor version.

.. describe:: guilabel

   Labels presented as part of an interactive user interface should be marked
   using ``guilabel``.  This includes labels from text-based interfaces such as
   those created using :mod:`curses` or other text-based libraries.  Any label
   used in the interface should be marked with this role, including button
   labels, window titles, field names, menu and menu selection names, and even
   values in selection lists.

.. describe:: kbd

   Mark a sequence of keystrokes.  What form the key sequence takes may depend
   on platform- or application-specific conventions.  When there are no relevant
   conventions, the names of modifier keys should be spelled out, to improve
   accessibility for new users and non-native speakers.  For example, an
   *xemacs* key sequence may be marked like ``:kbd:`C-x C-f```, but without
   reference to a specific application or platform, the same sequence should be
   marked as ``:kbd:`Control-x Control-f```.

.. describe:: mailheader

   The name of an RFC 822-style mail header.  This markup does not imply that
   the header is being used in an email message, but can be used to refer to any
   header of the same "style."  This is also used for headers defined by the
   various MIME specifications.  The header name should be entered in the same
   way it would normally be found in practice, with the camel-casing conventions
   being preferred where there is more than one common usage. For example:
   ``:mailheader:`Content-Type```.

.. describe:: makevar

   The name of a :command:`make` variable.

.. describe:: manpage

   A reference to a Unix manual page including the section,
   for example, ``:manpage:`ls(1)```.

.. describe:: menuselection

   Menu selections should be marked using the ``menuselection`` role.  This is
   used to mark a complete sequence of menu selections, including selecting
   submenus and choosing a specific operation, or any subsequence of such a
   sequence.  The names of individual selections should be separated by
   ``-->``.

   For example, to mark the selection "Start > Programs", use this markup::

      :menuselection:`Start --> Programs`

   When including a selection that includes some trailing indicator, such as the
   ellipsis some operating systems use to indicate that the command opens a
   dialog, the indicator should be omitted from the selection name.

.. describe:: mimetype

   The name of a MIME type, or a component of a MIME type (the major or minor
   portion, taken alone).

.. describe:: newsgroup

   The name of a Usenet newsgroup.

.. describe:: program

   The name of an executable program.  This may differ from the file name for
   the executable for some platforms.  In particular, the ``.exe`` (or other)
   extension should be omitted for Windows programs.

.. describe:: regexp

   A regular expression. Quotes should not be included.

.. describe:: samp

   A piece of literal text, such as code.  Within the contents, you can use
   curly braces to indicate a "variable" part, as in ``:file:``.

   If you don't need the "variable part" indication, use the standard
   ````code```` instead.

The following roles generate external links:

.. describe:: pep

   A reference to a Python Enhancement Proposal.  This generates appropriate
   index entries. The text "PEP *number*\ " is generated; in the HTML output,
   this text is a hyperlink to an online copy of the specified PEP. Such
   hyperlinks should not be a substitute for properly documenting the
   language in the manuals.

.. describe:: rfc

   A reference to an Internet Request for Comments.  This generates appropriate
   index entries. The text "RFC *number*\ " is generated; in the HTML output,
   this text is a hyperlink to an online copy of the specified RFC.

Note that there are no special roles for including hyperlinks as you can use the standard reST markup for that purpose.

Cross-linking markup

To support cross-referencing to arbitrary sections in the documentation, the standard reST labels are "abused" a bit: Every label must precede a section title; and every label name must be unique throughout the entire documentation source.

You can then reference to these sections using the :ref:`label-name` role.

Example:

.. _my-reference-label:

Section to cross-reference
--------------------------

This is the text of the section.

It refers to the section itself, see :ref:`my-reference-label`.

The :ref: invocation is replaced with the section title.

Alternatively, you can reference any label (not just section titles) if you provide the link text :ref:`link text <reference-label>`.

Paragraph-level markup

These directives create short paragraphs and can be used inside information units as well as normal text:

.. describe:: note

   An especially important bit of information about an API that a user should be
   aware of when using whatever bit of API the note pertains to.  The content of
   the directive should be written in complete sentences and include all
   appropriate punctuation.

   Example::

      .. note::

         This function is not suitable for sending spam e-mails.

.. describe:: warning

   An important bit of information about an API that a user should be aware of
   when using whatever bit of API the warning pertains to.  The content of the
   directive should be written in complete sentences and include all appropriate
   punctuation.  In the interest of not scaring users away from pages filled
   with warnings, this directive should only be chosen over ``note`` for
   information regarding the possibility of crashes, data loss, or security
   implications.

.. describe:: versionadded

   This directive documents the version of Python which added the described
   feature, or a part of it, to the library or C API.  When this applies to an
   entire module, it should be placed at the top of the module section before
   any prose.
   When adding a new API :ref:`with a directive <information-units>`
   (``class``, ``attribute``, ``function``, ``method``, ``c:type``, etc),
   a ``versionadded`` should be included at the end of its description block.

   The first argument must be given and is the version in question.
   Instead of a specific version number, you can---and should---use
   the word ``next``, indicating that the API will first appear in the
   upcoming release.
   The second argument is optional and can be used to describe the details of the feature.

   Example::

      .. function:: func()

         Return foo and bar.

         .. versionadded:: next

   When a release is made, the release manager will change the ``next`` to
   the just-released version. For example, if ``func`` in the above example is
   released in 3.14, the snippet will be changed to::

      .. function:: func()

         Return foo and bar.

         .. versionadded:: 3.14

   The tool to do this replacement is `update_version_next.py`_
   in the release-tools repository.

   .. _update_version_next.py: https://github.com/python/release-tools/blob/master/update_version_next.py

   When adding documentation for a function that existed in a past version,
   but wasn't documented yet, use the version number where the function was
   added instead of ``next``.

.. describe:: versionchanged

   Similar to ``versionadded``, but describes when and what changed in the named
   feature in some way (new parameters, changed side effects, platform support,
   etc.).  This one *must* have the second argument (explanation of the change).

   Example::

      .. function:: func(spam=False)

         Return foo and bar, optionally with *spam* applied.

         .. versionchanged:: next
            Added the *spam* parameter.

   Note that there should be no blank line between the directive head and the
   explanation; this is to make these blocks visually continuous in the markup.

.. describe:: deprecated

   Indicates the version from which the described feature is deprecated.

   There is one required argument: the version from which the feature is
   deprecated.
   Similarly to ``versionadded``, you should use the word ``next`` to indicate
   the API will be first deprecated in the upcoming release.

   Example::

      .. deprecated:: next

.. describe:: deprecated-removed

   Like ``deprecated``, but it also indicates in which version the feature is
   removed.

   There are two required arguments: the version from which the feature is
   deprecated (usually ``next``), and the version in which the feature
   is removed, which must be a specific version number (*not* ``next``).

   Example::

      .. deprecated-removed:: next 4.0

.. describe:: impl-detail

   This directive is used to mark CPython-specific information.  Use either with
   a block content or a single sentence as an argument, that is, either ::

      .. impl-detail::

         This describes some implementation detail.

         More explanation.

   or ::

      .. impl-detail:: This shortly mentions an implementation detail.

   "\ **CPython implementation detail:**\ " is automatically prepended to the
   content.

.. describe:: seealso

   Many sections include a list of references to module documentation or
   external documents.  These lists are created using the ``seealso`` directive.

   The ``seealso`` directive is typically placed in a section just before any
   sub-sections.  For the HTML output, it is shown boxed off from the main flow
   of the text.

   The content of the ``seealso`` directive should be a reST definition list.
   Example::

      .. seealso::

         Module :mod:`zipfile`
            Documentation of the :mod:`zipfile` standard module.

         `GNU tar manual, Basic Tar Format <http://link>`_
            Documentation for tar archive files, including GNU tar extensions.

.. describe:: rubric

   This directive creates a paragraph heading that is not used to create a
   table of contents node.  It is currently used for the "Footnotes" caption.

.. describe:: centered

   This directive creates a centered boldfaced paragraph.  Use it as follows::

      .. centered::

         Paragraph contents.

Table-of-contents markup

Since reST does not have facilities to interconnect several documents, or split documents into multiple output files, Sphinx uses a custom directive to add relations between the single files the documentation is made of, as well as tables of contents. The toctree directive is the central element.

.. describe:: toctree

   This directive inserts a "TOC tree" at the current location, using the
   individual TOCs (including "sub-TOC trees") of the files given in the
   directive body.  A numeric ``maxdepth`` option may be given to indicate the
   depth of the tree; by default, all levels are included.

   Consider this example (taken from the library reference index)::

      .. toctree::
         :maxdepth: 2

         intro
         strings
         datatypes
         numeric
         (many more files listed here)

   This accomplishes two things:

   * Tables of contents from all those files are inserted, with a maximum depth
     of two, that means one nested heading.  ``toctree`` directives in those
     files are also taken into account.
   * Sphinx knows that the relative order of the files ``intro``,
     ``strings`` and so forth, and it knows that they are children of the
     shown file, the library index.  From this information it generates "next
     chapter", "previous chapter" and "parent chapter" links.

   In the end, all files included in the build process must occur in one
   ``toctree`` directive; Sphinx will emit a warning if it finds a file that is
   not included, because that means that this file will not be reachable through
   standard navigation.

   The special file ``contents.rst`` at the root of the source directory is the
   "root" of the TOC tree hierarchy; from it the "Contents" page is generated.

Index-generating markup

Sphinx automatically creates index entries from all information units (like functions, classes or attributes) like discussed before.

However, there is also an explicit directive available, to make the index more comprehensive and enable index entries in documents where information is not mainly contained in information units, such as the language reference.

The directive is index and contains one or more index entries. Each entry consists of a type and a value, separated by a colon.

For example:

.. index::
   single: execution; context
   module: __main__
   module: sys
   triple: module; search; path

This directive contains five entries, which will be converted to entries in the generated index which link to the exact location of the index statement (or, in case of offline media, the corresponding page number).

The possible entry types are:

single
Creates a single index entry. Can be made a subentry by separating the subentry text with a semicolon (this notation is also used below to describe what entries are created).
pair
pair: loop; statement is a shortcut that creates two index entries, namely loop; statement and statement; loop.
triple
Likewise, triple: module; search; path is a shortcut that creates three index entries, which are module; search path, search; path, module and path; module search.
module, keyword, operator, object, exception, statement, builtin
These all create two index entries. For example, module: hashlib creates the entries module; hashlib and hashlib; module. The builtin entry type is slightly different in that "built-in function" is used in place of "builtin" when creating the two entries.

For index directives containing only "single" entries, there is a shorthand notation:

.. index:: BNF, grammar, syntax, notation

This creates four index entries.

Grammar production displays

Special markup is available for displaying the productions of a formal grammar. The markup is simple and does not attempt to model all aspects of BNF (or any derived forms), but provides enough to allow context-free grammars to be displayed in a way that causes uses of a symbol to be rendered as hyperlinks to the definition of the symbol. There is this directive:

.. describe:: productionlist

   This directive is used to enclose a group of productions.  Each production is
   given on a single line and consists of a name, separated by a colon from the
   following definition.  If the definition spans multiple lines, each
   continuation line must begin with a colon placed at the same column as in the
   first line.

   Blank lines are not allowed within ``productionlist`` directive arguments.

   The definition can contain token names which are marked as interpreted text
   (for example, ``unaryneg ::= "-" `integer```) -- this generates cross-references
   to the productions of these tokens.

   Note that no further reST parsing is done in the production, so that you
   don't have to escape ``*`` or ``|`` characters.

The following is an example taken from the Python Reference Manual:

.. productionlist::
   try_stmt: try1_stmt | try2_stmt
   try1_stmt: "try" ":" `suite`
            : ("except" [`expression` ["," `target`]] ":" `suite`)+
            : ["else" ":" `suite`]
            : ["finally" ":" `suite`]
   try2_stmt: "try" ":" `suite`
            : "finally" ":" `suite`

Substitutions

The documentation system provides three substitutions that are defined by default. They are set in the build configuration file :file:`conf.py`.

.. describe:: |release|

   Replaced by the Python release the documentation refers to.  This is the full
   version string including alpha/beta/release candidate tags, for example, ``2.5.2b3``.

.. describe:: |version|

   Replaced by the Python version the documentation refers to. This consists
   only of the major and minor version parts, for example, ``2.5``, even for version
   2.5.1.

.. describe:: |today|

   Replaced by either today's date, or the date set in the build configuration
   file.  Normally has the format ``April 14, 2007``.