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.

Cross-referencing anything

:any:

Nuevo en la versión 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 doc, ref or option.

    Custom objects added to the standard domain by extensions (see 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 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 any role also works together with the 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:

Cross-referencing arbitrary locations

: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 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>`.

Nota

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

Using 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

Nuevo en la versión 0.6.

There is also a way to directly link to documents:

: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

Nuevo en la versión 0.6.

: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

Nuevo en la versión 1.3.

Distinto en la versión 1.5: numref role can also refer sections. And numref allows {name} for the link text.

: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 numfig_format setting is used as fall-back default.

If 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:

:envvar:

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

:token:

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

:keyword:

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

:option:

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

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

: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.