.. highlight:: rst

=====
Roles
=====

Sphinx uses interpreted text roles to insert semantic markup into documents.
They are written as ``:rolename:`content```.

.. note::

   The default role (```content```) has no special meaning by default.  You are
   free to use it for anything you like, e.g. variable names; use the
   :confval:`default_role` config value to set it to a known role -- the
   :rst:role:`any` role to find anything or the :rst:role:`py:obj` role to find
   Python objects are very useful for this.

See :doc:`/usage/restructuredtext/domains` for roles added by domains.


.. _xref-syntax:

Cross-referencing syntax
------------------------

Cross-references are generated by many semantic interpreted text roles.
Basically, you only need to write ``:role:`target```, and a link will be
created to the item named *target* of the type indicated by *role*.  The link's
text will be the same as *target*.

There are some additional facilities, however, 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.

* If you prefix the content with ``~``, the link text will only be the last
  component of the target.  For example, ``:py:meth:`~Queue.Queue.get``` will
  refer to ``Queue.Queue.get`` but only display ``get`` as the link text.  This
  does not work with all cross-reference roles, but is domain specific.

  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.


.. _any-role:

Cross-referencing anything
^^^^^^^^^^^^^^^^^^^^^^^^^^

.. rst:role:: any

   .. versionadded:: 1.3

   This convenience role tries to do its best to find a valid target for its
   reference text.

   * First, it tries standard cross-reference targets that would be referenced
     by :rst:role:`doc`, :rst:role:`ref` or :rst:role:`option`.

     Custom objects added to the standard domain by extensions (see
     :meth:`.Sphinx.add_object_type`) are also searched.

   * Then, it looks for objects (targets) in all loaded domains.  It is up to
     the domains how specific a match must be.  For example, in the Python
     domain a reference of ``:any:`Builder``` would match the
     ``sphinx.builders.Builder`` class.

   If none or multiple targets are found, a warning will be emitted.  In the
   case of multiple targets, you can change "any" to a specific role.

   This role is a good candidate for setting :confval:`default_role`.  If you
   do, you can write cross-references without a lot of markup overhead.  For
   example, in this Python function documentation ::

      .. function:: install()

         This function installs a `handler` for every signal known by the
         `signal` module.  See the section `about-signals` for more information.

   there could be references to a glossary term (usually ``:term:`handler```), a
   Python module (usually ``:py:mod:`signal``` or ``:mod:`signal```) and a
   section (usually ``:ref:`about-signals```).

   The :rst:role:`any` role also works together with the
   :mod:`~sphinx.ext.intersphinx` extension: when no local cross-reference is
   found, all object types of intersphinx inventories are also searched.

Cross-referencing objects
^^^^^^^^^^^^^^^^^^^^^^^^^

These roles are described with their respective domains:

* :ref:`Python <python-roles>`
* :ref:`C <c-roles>`
* :ref:`C++ <cpp-roles>`
* :ref:`JavaScript <js-roles>`
* :ref:`ReST <rst-roles>`


.. _ref-role:

Cross-referencing arbitrary locations
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

.. rst:role:: ref

   To support cross-referencing to arbitrary locations in any document, the
   standard reST labels are used.  For this to work label names must be unique
   throughout the entire documentation.  There are two ways in which you can
   refer to labels:

   * If you place a label directly before a section title, you can reference to
     it with ``:ref:`label-name```.  For 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:`` role would then generate a link to the section, with the
     link title being "Section to cross-reference".  This works just as well
     when section and reference are in different source files.

     Automatic labels also work with figures. For example::

        .. _my-figure:

        .. figure:: whatever

           Figure caption

     In this case, a  reference ``:ref:`my-figure``` would insert a reference
     to the figure with link text "Figure caption".

     The same works for tables that are given an explicit caption using the
     :dudir:`table` directive.

   * Labels that aren't placed before a section title can still be referenced,
     but you must give the link an explicit title, using this syntax:
     ``:ref:`Link title <label-name>```.

   .. note::

      Reference labels must start with an underscore. When referencing a label,
      the underscore must be omitted (see examples above).

   Using :rst:role:`ref` is advised over standard reStructuredText links to
   sections (like ```Section title`_``) because it works across files, when
   section headings are changed, will raise warnings if incorrect, and works
   for all builders that support cross-references.


Cross-referencing documents
^^^^^^^^^^^^^^^^^^^^^^^^^^^

.. versionadded:: 0.6

There is also a way to directly link to documents:

.. rst:role:: doc

   Link to the specified document; the document name can be specified in
   absolute or relative fashion.  For example, if the reference
   ``:doc:`parrot``` occurs in the document ``sketches/index``, then the link
   refers to ``sketches/parrot``.  If the reference is ``:doc:`/people``` or
   ``:doc:`../people```, the link refers to ``people``.

   If no explicit link text is given (like usual: ``:doc:`Monty Python members
   </people>```), the link caption will be the title of the given document.


Referencing downloadable files
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

.. versionadded:: 0.6

.. rst:role:: download

   This role lets you link to files within your source tree that are not reST
   documents that can be viewed, but files that can be downloaded.

   When you use this role, the referenced file is automatically marked for
   inclusion in the output when building (obviously, for HTML output only).
   All downloadable files are put into a ``_downloads/<unique hash>/``
   subdirectory of the output directory; duplicate filenames are handled.

   An example::

      See :download:`this example script <../example.py>`.

   The given filename is usually relative to the directory the current source
   file is contained in, but if it absolute (starting with ``/``), it is taken
   as relative to the top source directory.

   The ``example.py`` file will be copied to the output directory, and a
   suitable link generated to it.

   Not to show unavailable download links, you should wrap whole paragraphs that
   have this role::

      .. only:: builder_html

         See :download:`this example script <../example.py>`.

Cross-referencing figures by figure number
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

.. versionadded:: 1.3

.. versionchanged:: 1.5
   `numref` role can also refer sections.
   And `numref` allows `{name}` for the link text.

.. rst:role:: numref

   Link to the specified figures, tables, code-blocks and sections; the standard
   reST labels are used.  When you use this role, it will insert a reference to
   the figure with link text by its figure number like "Fig. 1.1".

   If an explicit link text is given (as usual: ``:numref:`Image of Sphinx (Fig.
   %s) <my-figure>```), the link caption will serve as title of the reference.
   As placeholders, `%s` and `{number}` get replaced by the figure
   number and  `{name}` by the figure caption.
   If no explicit link text is given, the :confval:`numfig_format` setting is
   used as fall-back default.

   If :confval:`numfig` is ``False``, figures are not numbered,
   so this role inserts not a reference but the label or the link text.

Cross-referencing other items of interest
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

The following roles do possibly create a cross-reference, but do not refer to
objects:

.. rst:role:: envvar

   An environment variable.  Index entries are generated.  Also generates a link
   to the matching :rst:dir:`envvar` directive, if it exists.

.. rst:role:: token

   The name of a grammar token (used to create links between
   :rst:dir:`productionlist` directives).

.. rst:role:: keyword

   The name of a keyword in Python.  This creates a link to a reference label
   with that name, if it exists.

.. rst:role:: option

   A command-line option to an executable program.  This generates a link to
   a :rst:dir:`option` directive, if it exists.


The following role creates a cross-reference to a term in a
:ref:`glossary <glossary-directive>`:

.. rst:role:: term

   Reference to a term in a glossary.  A 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,
   for example 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.

Inline code highlighting
------------------------

.. rst:role:: code

   An *inline* code example.  When used directly, this role just displays the
   text *without* syntax highlighting, as a literal.

   .. code-block:: rst

      By default, inline code such as :code:`1 + 2` just displays without
      highlighting.

   Unlike the :rst:dir:`code-block` directive, this role does not respect the
   default language set by the :rst:dir:`highlight` directive.

   To enable syntax highlighting, you must first use the Docutils :dudir:`role`
   directive to define a custom role associated with a specific language:

   .. code-block:: rst

      .. role:: python(code)
         :language: python

      In Python, :python:`1 + 2` is equal to :python:`3`.

   To display a multi-line code example, use the :rst:dir:`code-block` directive
   instead.

Math
----

.. rst:role:: math

   Role for inline math.  Use like this::

      Since Pythagoras, we know that :math:`a^2 + b^2 = c^2`.

.. rst:role:: eq

   Same as :rst:role:`math:numref`.


Other semantic markup
---------------------

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

.. rst:role:: abbr

   An abbreviation.  If the role content contains a parenthesized explanation,
   it will be treated specially: it will be shown in a tool-tip in HTML, and
   output only once in LaTeX.

   Example: ``:abbr:`LIFO (last-in, first-out)```.

   .. versionadded:: 0.6

.. rst:role:: command

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

.. rst:role:: dfn

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

.. rst:role:: 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/python3.{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.

.. rst:role:: 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.

   .. versionchanged:: 1.0
      An accelerator key for the GUI label can be included using an ampersand;
      this will be stripped and displayed underlined in the output (example:
      ``:guilabel:`&Cancel```).  To include a literal ampersand, double it.

.. rst:role:: 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```.

.. rst:role:: 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```.

.. rst:role:: makevar

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

.. rst:role:: manpage

   A reference to a Unix manual page including the section, e.g.
   ``:manpage:`ls(1)```. Creates a hyperlink to an external site rendering the
   manpage if :confval:`manpages_url` is defined.

.. rst:role:: 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.

   ``menuselection`` also supports ampersand accelerators just like
   :rst:role:`guilabel`.

.. rst:role:: mimetype

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

.. rst:role:: newsgroup

   The name of a Usenet newsgroup.

.. todo:: Is this not part of the standard domain?

.. rst:role:: 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.

.. rst:role:: regexp

   A regular expression. Quotes should not be included.

.. rst:role:: samp

   A piece of literal text, such as code.  Within the contents, you can use
   curly braces to indicate a "variable" part, as in :rst:role:`file`.  For
   example, in ``:samp:`print 1+{variable}```, the part ``variable`` would be
   emphasized.

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

   .. versionchanged:: 1.8
      Allowed to escape curly braces with backslash

There is also an :rst:role:`index` role to generate index entries.

The following roles generate external links:

.. rst:role:: 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.  You can
   link to a specific section by saying ``:pep:`number#anchor```.

.. rst:role:: 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.  You can
   link to a specific section by saying ``:rfc:`number#anchor```.


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


.. _default-substitutions:

Substitutions
-------------

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

.. describe:: |release|

   Replaced by the project release the documentation refers to.  This is meant
   to be the full version string including alpha/beta/release candidate tags,
   e.g. ``2.5.2b3``.  Set by :confval:`release`.

.. describe:: |version|

   Replaced by the project version the documentation refers to. This is meant to
   consist only of the major and minor version parts, e.g. ``2.5``, even for
   version 2.5.1.  Set by :confval:`version`.

.. describe:: |today|

   Replaced by either today's date (the date on which the document is read), or
   the date set in the build configuration file.  Normally has the format
   ``April 14, 2007``.  Set by :confval:`today_fmt` and :confval:`today`.
