Add a helloworld tutorial

doc/develop.rst

@@ -100,7 +100,7 @@ This is the current list of contributed extensions in that repository:
 - zopeext: provide an ``autointerface`` directive for using `Zope interfaces`_
 
 
-See the :ref:`extension tutorial <exttuttodo>` on getting started with writing your
+See the :ref:`extension tutorial <exttuto-todo>` on getting started with writing your
 own extensions.
 
 

doc/extdev/tutorials/helloworld_ext.rst

@@ -0,0 +1,150 @@
+.. _exttuto-helloworld:
+
+Developing a "Hello world" directive
+====================================
+
+The objective of this tutorial is to create a very basic extension that adds a new
+directive that outputs a paragraph containing `hello world`.
+
+Only basic information is provided in this tutorial. For more information,
+refer to the :ref:`other tutorials <extensiontutos>` that go into more
+details.
+
+.. warning:: For this extension, you will need some basic understanding of docutils_
+   and Python.
+
+Creating a new extension file
+-----------------------------
+
+Your extension file could be in any folder of your project. In our case,
+let's do the following:
+
+#. Create an :file:`_ext` folder in :file:`source`.
+#. Create a new Python file in the :file:`_ext` folder called
+   :file:`helloworld.py`.
+
+   Here is an example of the folder structure you might obtain:
+
+   .. code-block:: text
+
+         └── source
+             ├── _ext
+             │   └── helloworld.py
+             ├── _static
+             ├── _themes
+             ├── conf.py
+             ├── somefolder
+             ├── somefile.rst
+             └── someotherfile.rst
+
+Writing the extension
+---------------------
+
+Open :file:`helloworld.py` and paste the following code in it:
+
+.. code-block:: python
+
+   from docutils import nodes
+   from docutils.parsers.rst import Directive
+
+
+   class HelloWorld(Directive):
+       def run(self):
+           paragraph_node = nodes.paragraph(text='Hello World!')
+           return [paragraph_node]
+
+
+   def setup(app):
+       app.add_directive("helloworld", HelloWorld)
+
+
+Some essential things are happening in this example, and you will see them
+in all directives:
+
+.. rubric:: Directive declaration
+
+Our new directive is declared in the :code:`HelloWorld` class, it extends
+docutils_' code:`Directive` class. All extensions that create directives
+should extend this class.
+
+.. rubric:: `run` method
+
+This method is a requirement and it is part of every directive. It contains
+the main logic of the directive and it returns a list of docutils nodes to
+be processed by Sphinx.
+
+Read more on this topic in :ref:`exttuto-todo`.
+
+.. rubric:: docutils nodes
+
+The `run` method returns a list of nodes. Nodes are docutils' way of
+representing the content of a document. There are many types of nodes
+available: text, paragraph, reference, table, etc.
+
+Read more about `docutils nodes`_.
+
+You can also create your own nodes if needed, refer to the
+:ref:`exttuto-todo` for more information.
+
+The :code:`nodes.paragraph` method creates a new paragraph node. A paragraph
+node typically contains some text that we can set during instantiation using
+the ``text`` parameter.
+
+.. rubric:: `setup` method
+
+This method is a requirement. We use it to plug our new directive into
+Sphinx. The first argument is the name of the directive itself. In our case:
+
+.. code-block:: rst
+
+   Some intro text here...
+
+   .. helloworld::
+
+   Some more text here...
+
+
+Updating the conf.py file
+-------------------------
+
+The extension file has to be declared in your :file:`conf.py` file to make
+Sphinx aware of it:
+
+#. Open :file:`conf.py`. It is in the :file:`source` folder by default.
+#. Add :code:`sys.path.append(os.path.abspath("./_ext"))` before
+   the ``extensions`` variable declaration (if it exists).
+#. Update of create the ``extensions`` list and add the
+   extension file name to the list:
+
+   .. code-block:: python
+
+      extensions.append('helloworld')
+
+You can now use the extension.
+
+.. admonition:: Example
+
+   .. code-block:: rst
+
+      Some intro text here...
+
+      .. helloworld::
+
+      Some more text here...
+
+   The sample above would generate:
+
+   .. code-block:: text
+
+      Some intro text here...
+
+      Hello World!
+
+      Some more text here...
+
+This is the very basic principle of an extension that creates a new directive.
+
+For a more advanced example, refer to :ref:`exttuto-todo`
+
+.. _docutils: http://docutils.sourceforge.net/
+.. _`docutils nodes`: http://docutils.sourceforge.net/docs/ref/doctree.html

doc/extdev/tutorials/index.rst

@@ -1,4 +1,4 @@
-.. _exttuttodoorials:
+.. _extensiontutos:
 
 Extension tutorials
 ===================
@@ -6,5 +6,8 @@ Extension tutorials
 Refer to the following tutorials to get started with extension development.
 
 .. toctree::
+   :caption: Directive tutorials
+   :maxdepth: 1
 
+   helloworld_ext
    todo_ext

doc/extdev/tutorials/todo_ext.rst

@@ -1,6 +1,6 @@
-.. _exttuttodo:
+.. _exttuto-todo:
 
-Developing a `TODO` extension
+Developing a "TODO" extension
 =============================
 
 This section is intended as a walkthrough for the creation of custom extensions.

doc/faq.rst

@@ -33,7 +33,7 @@ How do I...
    ``sidebartoc`` block.
 
 ... write my own extension?
-   See the :ref:`extension tutorial <exttuttodo>`.
+   See the :ref:`extension tutorial <exttuto-todo>`.
 
 ... convert from my existing docs using MoinMoin markup?
    The easiest way is to convert to xhtml, then convert `xhtml to reST`_.