
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
=======================

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 <guido@python.org>

   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 <eric@python.invalid>
   .. moduleauthor:: John Idle <john@python.invalid>

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

module

   This directive marks the beginning of the description of a module,
   package, or submodule. The name should be fully qualified (i.e.
   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.

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 always
include the type name (``.. method:: FileInput.input(...)``), even if
it is obvious from the context which type they belong to; this is to
enable consistent cross-references.  If you describe methods belonging
to an abstract protocol, such as "context managers", include a
(pseudo-)type name too to make the index entries more informative.

The directives are:

cfunction

   Describes a C function. The signature should be given as in C,
   e.g.:

      .. cfunction:: 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.

cmember

   Describes a C struct member. Example signature:

      .. cmember:: 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.

cmacro

   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 ``PyObject_HEAD`` and
   ``Py_BEGIN_ALLOW_THREADS``.

ctype

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

cvar

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

      .. cvar:: PyObject* PyClass_Type

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 environment.

exception

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

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:: Timer.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.

class

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

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.

method

   Describes an object method.  The parameters should not include the
   ``self`` parameter.  The description should include similar
   information to that described for ``function``.

opcode

   Describes a Python *bytecode* instruction.

cmdoption

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

      .. cmdoption:: -m <module>

         Run a module as a script.

envvar

   Describes an environment variable that Python uses or defines.

There is also a generic version of these directives:

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
presented, there should not be an "unused" primary prompt; this is an
example of what *not* to do:

   >>> 1 + 1
   2
   >>>

Syntax highlighting is handled in a smart way:

* There is a "highlighting language" for each source file.  Per
  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 ``highlightlang``
  directive, used as follows:

     .. highlightlang:: c

  This language is used until the next ``highlightlang`` directive is
  encountered.

* 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. [1] For
example, to include the Python source 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.


Inline markup
=============

As said before, Sphinx uses interpreted text roles to insert semantic
markup in documents.

Names of local variables, such as function/method arguments, are an
exception, they should be marked simply with ``*var*``.

For all other roles, you have to write ``:rolename:`content```.

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 is e.g. shown
  as a tool-tip on mouse-hover) will always be the full target name.

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

mod

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

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.

data

   The name of a module-level variable or constant.

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.

class

   A class name; a dotted name may be used.

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.

attr

   The name of a data attribute of an object.

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 ``codecs`` module, ``:func:`open``` always refers
to the built-in function, while ``:func:`.open``` refers to
``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:

cdata

   The name of a C-language variable.

cfunc

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

cmacro

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

ctype

   The name of a C-language type.

The following role does possibly create a cross-reference, but does
not refer to objects:

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:

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:

command

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

dfn

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

envvar

   An environment variable.  Index entries are generated.

file

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

      ... 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.

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 ``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.

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```.

keyword

   The name of a keyword in Python.

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```.

makevar

   The name of a **make** variable.

manpage

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

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.

mimetype

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

newsgroup

   The name of a Usenet newsgroup.

option

   A command-line option to an executable program.  The leading
   hyphen(s) must be included.

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.

regexp

   A regular expression. Quotes should not be included.

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.

var

   A Python or C variable or parameter name.

The following roles generate external links:

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.

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.


Paragraph-level markup
======================

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

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.

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.  This should
   only be chosen over ``note`` for information regarding the
   possibility of crashes, data loss, or security implications.

versionadded

   This directive documents the version of Python which added the
   described feature 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.

   The first argument must be given and is the version in question;
   you can add a second argument consisting of a *brief* explanation
   of the change.

   Example:

      .. versionadded:: 3.1
         The *spam* parameter.

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

versionchanged

   Similar to ``versionadded``, but describes when and what changed in
   the named feature in some way (new parameters, changed side
   effects, etc.).

======================================================================

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.

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.

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.

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.rst
         strings.rst
         datatypes.rst
         numeric.rst
         (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.rst``,
     ``strings.rst`` 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``.

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:

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 (e.g. ``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 ``conf.py``.

|release|

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

|version|

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

|today|

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

-[ Footnotes ]-

[1] There is a standard ``.. include`` directive, but it raises errors
    if the file is not found.  This one only emits a warning.
