Expand the markup chapter a bit.

doc/markup/code.rst

@@ -0,0 +1,94 @@
+.. highlight:: rest
+
+Showing code examples
+---------------------
+
+Examples of Python source code or interactive sessions are represented using
+standard reST literal blocks.  They are started by a ``::`` at the end of the
+preceding paragraph and delimited by indentation.
+
+Representing an interactive session requires including the prompts and output
+along with the Python code.  No special markup is required for interactive
+sessions.  After the last line of input or output presented, there should not be
+an "unused" primary prompt; this is an example of what *not* to do::
+
+   >>> 1 + 1
+   2
+   >>>
+
+Syntax highlighting is done with `Pygments <http://pygments.org>`_ (if it's
+installed) and handled in a smart way:
+
+* There is a "highlighting language" for each source file.  Per default, this is
+  ``'python'`` as the majority of files will have to highlight Python snippets.
+
+* Within Python highlighting mode, interactive sessions are recognized
+  automatically and highlighted appropriately.
+
+* The highlighting language can be changed using the ``highlight`` directive,
+  used as follows::
+
+     .. highlight:: c
+
+  This language is used until the next ``highlight`` directive is encountered.
+
+* For documents that have to show snippets in different languages, there's also
+  a :dir:`code-block` directive that is given the highlighting language
+  directly::
+
+     .. code-block:: ruby
+
+        Some Ruby code.
+
+  The directive's alias name :dir:`sourcecode` works as well.
+
+* The valid values for the highlighting language are:
+
+  * ``none`` (no highlighting)
+  * ``python`` (the default)
+  * ``rest``
+  * ``c``
+  * ... and any other lexer name that Pygments supports.
+
+* If highlighting with the selected language fails, the block is not highlighted
+  in any way.
+
+Line numbers
+^^^^^^^^^^^^
+
+If installed, Pygments can generate line numbers for code blocks.  For
+automatically-highlighted blocks (those started by ``::``), line numbers must be
+switched on in a :dir:`highlight` directive, with the ``linenothreshold``
+option::
+
+   .. highlight:: python
+      :linenothreshold: 5
+
+This will produce line numbers for all code blocks longer than five lines.
+
+For :dir:`code-block` blocks, a ``linenos`` flag option can be given to switch
+on line numbers for the individual block::
+
+   .. code-block:: ruby
+      :linenos:
+
+      Some more Ruby code.
+
+
+Includes
+^^^^^^^^
+
+Longer displays of verbatim text may be included by storing the example text in
+an external file containing only plain text.  The file may be included using the
+``literalinclude`` directive. [1]_ For example, to include the Python source file
+:file:`example.py`, use::
+
+   .. literalinclude:: example.py
+
+The file name is relative to the current file's path.
+
+
+.. rubric:: Footnotes
+
+.. [1] There is a standard ``.. include`` directive, but it raises errors if the
+       file is not found.  This one only emits a warning.