sphinx/doc/extdev/markupapi.rst
2024-07-03 02:09:15 +01:00

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ReStructuredText

Docutils markup API
===================
This section describes the API for adding reStructuredText markup elements
(roles and directives).
Roles
-----
Roles follow the interface described below.
They have to be registered by an extension using
:meth:`.Sphinx.add_role` or :meth:`.Sphinx.add_role_to_domain`.
.. code-block:: python
def role_function(
role_name: str, raw_source: str, text: str,
lineno: int, inliner: Inliner,
options: dict = {}, content: list = [],
) -> tuple[list[Node], list[system_message]]:
elements = []
messages = []
return elements, messages
The *options* and *content* parameters are only used for custom roles
created via the :dudir:`role` directive.
The return value is a tuple of two lists,
the first containing the text nodes and elements from the role,
and the second containing any system messages generated.
For more information, see the `custom role overview`_ from Docutils.
.. _custom role overview: https://docutils.sourceforge.io/docs/howto/rst-roles.html
Creating custom roles
^^^^^^^^^^^^^^^^^^^^^
Sphinx provides two base classes for creating custom roles,
:class:`~sphinx.util.docutils.SphinxRole` and :class:`~sphinx.util.docutils.ReferenceRole`.
These provide a class-based interface for creating roles,
where the main logic must be implemented in your ``run()`` method.
The classes provide a number of useful methods and attributes,
such as ``self.text``, ``self.config``, and ``self.env``.
The ``ReferenceRole`` class implements Sphinx's ``title <target>`` logic,
exposing ``self.target`` and ``self.title`` attributes.
This is useful for creating cross-reference roles.
Directives
----------
Directives are handled by classes derived from
``docutils.parsers.rst.Directive``. They have to be registered by an extension
using :meth:`.Sphinx.add_directive` or :meth:`.Sphinx.add_directive_to_domain`.
.. module:: docutils.parsers.rst
.. class:: Directive
The markup syntax of the new directive is determined by the follow five class
attributes:
.. autoattribute:: required_arguments
.. autoattribute:: optional_arguments
.. autoattribute:: final_argument_whitespace
.. autoattribute:: option_spec
Option validator functions take a single parameter, the option argument
(or ``None`` if not given), and should validate it or convert it to the
proper form. They raise :exc:`ValueError` or :exc:`TypeError` to indicate
failure.
There are several predefined and possibly useful validators in the
:mod:`docutils.parsers.rst.directives` module.
.. autoattribute:: has_content
New directives must implement the :meth:`run` method:
.. method:: run()
This method must process the directive arguments, options and content, and
return a list of Docutils/Sphinx nodes that will be inserted into the
document tree at the point where the directive was encountered.
Instance attributes that are always set on the directive are:
.. attribute:: name
The directive name (useful when registering the same directive class under
multiple names).
.. attribute:: arguments
The arguments given to the directive, as a list.
.. attribute:: options
The options given to the directive, as a dictionary mapping option names
to validated/converted values.
.. attribute:: content
The directive content, if given, as a :class:`!ViewList`.
.. attribute:: lineno
The absolute line number on which the directive appeared. This is not
always a useful value; use :attr:`srcline` instead.
.. attribute:: content_offset
Internal offset of the directive content. Used when calling
``nested_parse`` (see below).
.. attribute:: block_text
The string containing the entire directive.
.. attribute:: state
state_machine
The state and state machine which controls the parsing. Used for
``nested_parse``.
.. seealso::
`Creating directives`_ HOWTO of the Docutils documentation
.. _Creating directives: https://docutils.sourceforge.io/docs/howto/rst-directives.html
.. _parsing-directive-content-as-rest:
Parsing directive content as reStructuredText
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Many directives will contain more markup that must be parsed.
To do this, use one of the following APIs from the :meth:`~Directive.run` method:
* :py:meth:`.SphinxDirective.parse_content_to_nodes()`
* :py:meth:`.SphinxDirective.parse_text_to_nodes()`
The first method parses all the directive's content as markup,
whilst the second only parses the given *text* string.
Both methods return the parsed Docutils nodes in a list.
The methods are used as follows:
.. code-block:: python
def run(self) -> list[Node]:
# either
parsed = self.parse_content_to_nodes()
# or
parsed = self.parse_text_to_nodes('spam spam spam')
return parsed
.. note::
The above utility methods were added in Sphinx 7.4.
Prior to Sphinx 7.4, the following methods should be used to parse content:
* ``self.state.nested_parse``
* :func:`sphinx.util.nodes.nested_parse_with_titles` -- this allows titles in
the parsed content.
.. code-block:: python
def run(self) -> list[Node]:
container = docutils.nodes.Element()
# either
nested_parse_with_titles(self.state, self.result, container)
# or
self.state.nested_parse(self.result, 0, container)
parsed = container.children
return parsed
To parse inline markup,
use :py:meth:`~sphinx.util.docutils.SphinxDirective.parse_inline()`.
This must only be used for text which is a single line or paragraph,
and does not contain any structural elements
(headings, transitions, directives, etc).
.. note::
``sphinx.util.docutils.switch_source_input()`` allows changing
the source (input) file during parsing content in a directive.
It is useful to parse mixed content, such as in ``sphinx.ext.autodoc``,
where it is used to parse docstrings.
.. code-block:: python
from sphinx.util.docutils import switch_source_input
from sphinx.util.parsing import nested_parse_to_nodes
# Switch source_input between parsing content.
# Inside this context, all parsing errors and warnings are reported as
# happened in new source_input (in this case, ``self.result``).
with switch_source_input(self.state, self.result):
parsed = nested_parse_to_nodes(self.state, self.result)
.. deprecated:: 1.7
Until Sphinx 1.6, ``sphinx.ext.autodoc.AutodocReporter`` was used for this
purpose. It is replaced by ``switch_source_input()``.
.. _ViewLists:
ViewLists and StringLists
^^^^^^^^^^^^^^^^^^^^^^^^^
Docutils represents document source lines in a ``StringList`` class,
which inherits from ``ViewList``, both in the ``docutils.statemachine`` module.
This is a list with extended functionality,
including that slicing creates views of the original list and
that the list contains information about source line numbers.
The :attr:`Directive.content` attribute is a ``StringList``.
If you generate content to be parsed as reStructuredText,
you have to create a ``StringList`` for the Docutils APIs.
The utility functions provided by Sphinx handle this automatically.
Important for content generation are the following points:
* The ``ViewList`` constructor takes a list of strings (lines)
and a source (document) name.
* The ``ViewList.append()`` method takes a line and a source name as well.