Documentation
The Apache NuttX Documentation is built using the Sphinx documentation system. Documentation is written in ReStructured Text (RST), with Sphinx-specific directives. RST is the format used for Python documentation and is also used in many other projects. Using Sphinx, the RST files are rendered into HTML files that can be read in your browser.
Building
To render the Documentation locally, you should clone the NuttX main repository, and
go into Documentation
directory. Then,
Install Sphinx and other dependencies using pipenv. You may also find it helpful on platforms such as Windows and MacOS to use pyenv to manage your python installation. You can read about installing that on the project site.
$ pip3 install pipenv $ pipenv install $ # activate the virtual environment $ pipenv shell
Build documentation:
$ make html
The resulting HTMLs will end up under
_build/html
. You can open your browser at the root with:$ xdg-open _build/html/index.html
Live Rebuild
For more comfortable editing and previewing of changes (as make html
will perform a slower full rebuild),
you can install sphinx-autobuild
which will monitor file changes and rebuild only affected files. To
install it (within the virtual environment):
$ pip3 install sphinx-autobuild
To run:
$ make autobuild
Which will perform an initial clean build and monitor changes from then on.
Contributing
Contributions to documentation are appreciated. These can be as simple as fixing a typo or formatting issues to more involved changes such as documenting parts of NuttX which are not yet covered or even writing guides for other users.
The contribution workflow is the same as for the code, so check the Development Workflow to understand how your changes should be upstreamed.
Writing ReStructure Text with Sphinx
The following links can be used to learn about RST syntax and about Sphinx specific directives. Note that
sometimes Sphinx’s approach is used over standard RST since it is more powerful (e.g. standard linking vs Sphinx
:ref:
which can be used across files, code-block
directive vs ::
which allows specifying highlight language, etc.):
Documentation Conventions
While RST/Sphinx provide many ways to do things, it is best to follow a given convention to maintain consistency and avoid pitfalls. For this reason, documentation changes should follow the following set of conventions.
Indentation
Child blocks should be indented two-spaces. This includes itemizations/enumerations.
Headings
Three levels of headings should be used in general. The style used to mark sections is based around =
and -
.
Sections should look like this:
=================
Top Level Heading
=================
Subsection
==========
Subsubsection
-------------
Code
Code should be documented using the C domain. This means for example that a function should be documented as:
.. c:function:: bool myfunction(int arg1, int arg2)
Here the function should be described
:param arg1: Description of arg1
:param arg2: Description of arg2
:return: Description of return value
To document a piece of code, use a code-block
directive, specifying the highlight language. If the block is not of code but some verbatim piece of text,
it is acceptable to use RST standard ::. This is specially useful and compact when used in the following mode:
The text file should have the following content::
Line1
Line2
Line3
Linking
To generate internal links, Sphinx’s roles should
be used. So, use :ref:
instead of standard RST syntax like `link <target>`_
for internal links.
If the target is in a different file, you can refer it with: :ref:`link text </pathtorst:Section Name>`
.
Linking to a specific document can be done with :doc:`/path/to/document`
(without .rst
extension).
Notes and TODOS
Use RST admonitions to highlight things from the text, such as a note that should be prominently displayed.
In case you need to leave a TODO note in the documentation to point that something needs to be improved, use a todo
admonition,
which is available via the sphinx.ext.todo
extension. This will let the reader of the documentation also know that the documentation
is not yet finished somewhere and may further motivate a contribution.
User Indications
To indicate a keypress, menu action or GUI button selection, use the following:
Go into menu :menuselection:`File --> Save As`, click :guilabel:`&OK` or press :kbd:`Enter`.
which would render as:
Go into menu OK or press Enter.
, clickTabbed examples
To indicate different instructions/examples for different scenarios (for example, different Operating Systems) use the tabs extension (see link for examples).
Tips
Spacing
If you are getting formatting errors, be sure to provide the appropriate spacing between a directive and its content. Generally, you should follow this format:
.. directive::
child content
non-child content which appears after previous directive
Note the line between directive and content and the indentation.