
reStructuredText Primer
***********************

This section is a brief introduction to reStructuredText (reST)
concepts and syntax, intended to provide authors with enough
information to author documents productively.  Since reST was designed
to be a simple, unobtrusive markup language, this will not take too
long.

See also:

   The authoritative reStructuredText User Documentation.  The "ref"
   links in this document link to the description of the individual
   constructs in the reST reference.


Paragraphs
==========

The paragraph (ref) is the most basic block in a reST document.
Paragraphs are simply chunks of text separated by one or more blank
lines.  As in Python, indentation is significant in reST, so all lines
of the same paragraph must be left-aligned to the same level of
indentation.


Inline markup
=============

The standard reST inline markup is quite simple: use

* one asterisk: ``*text*`` for emphasis (italics),

* two asterisks: ``**text**`` for strong emphasis (boldface), and

* backquotes: ````text```` for code samples.

If asterisks or backquotes appear in running text and could be
confused with inline markup delimiters, they have to be escaped with a
backslash.

Be aware of some restrictions of this markup:

* it may not be nested,

* content may not start or end with whitespace: ``* text*`` is wrong,

* it must be separated from surrounding text by non-word characters.
  Use a backslash escaped space to work around that: ``thisis\ *one*\
  word``.

These restrictions may be lifted in future versions of the docutils.

reST also allows for custom "interpreted text roles"', which signify
that the enclosed text should be interpreted in a specific way.
Sphinx uses this to provide semantic markup and cross-referencing of
identifiers, as described in the appropriate section.  The general
syntax is ``:rolename:`content```.

Standard reST provides the following roles:

* emphasis -- alternate spelling for ``*emphasis*``

* strong -- alternate spelling for ``**strong**``

* literal -- alternate spelling for ````literal````

* subscript -- subscript text

* superscript -- superscript text

* title-reference -- for titles of books, periodicals, and other
  materials

See *Inline markup* for roles added by Sphinx.


Lists and Quote-like blocks
===========================

List markup (ref) is natural: just place an asterisk at the start of a
paragraph and indent properly.  The same goes for numbered lists; they
can also be autonumbered using a ``#`` sign:

   * This is a bulleted list.
   * It has two items, the second
     item uses two lines.

   1. This is a numbered list.
   2. It has two items too.

   #. This is a numbered list.
   #. It has two items too.

Nested lists are possible, but be aware that they must be separated
from the parent list items by blank lines:

   * this is
   * a list

     * with a nested list
     * and some subitems

   * and here the parent list continues

Definition lists (ref) are created as follows:

   term (up to a line of text)
      Definition of the term, which must be indented

      and can even consist of multiple paragraphs

   next term
      Description.

Note that the term cannot have more than one line of text.

Quoted paragraphs (ref) are created by just indenting them more than
the surrounding paragraphs.

Line blocks (ref) are a way of preserving line breaks:

   | These lines are
   | broken exactly like in
   | the source file.

There are also several more special blocks available:

* field lists (ref)

* option lists (ref)

* quoted literal blocks (ref)

* doctest blocks (ref)


Source Code
===========

Literal code blocks (ref) are introduced by ending a paragraph with
the special marker ``::``.  The literal block must be indented (and,
like all paragraphs, separated from the surrounding ones by blank
lines):

   This is a normal text paragraph. The next paragraph is a code sample::

      It is not processed in any way, except
      that the indentation is removed.

      It can span multiple lines.

   This is a normal text paragraph again.

The handling of the ``::`` marker is smart:

* If it occurs as a paragraph of its own, that paragraph is completely
  left out of the document.

* If it is preceded by whitespace, the marker is removed.

* If it is preceded by non-whitespace, the marker is replaced by a
  single colon.

That way, the second sentence in the above example's first paragraph
would be rendered as "The next paragraph is a code sample:".


Tables
======

Two forms of tables are supported.  For *grid tables* (ref), you have
to "paint" the cell grid yourself.  They look like this:

   +------------------------+------------+----------+----------+
   | Header row, column 1   | Header 2   | Header 3 | Header 4 |
   | (header rows optional) |            |          |          |
   +========================+============+==========+==========+
   | body row 1, column 1   | column 2   | column 3 | column 4 |
   +------------------------+------------+----------+----------+
   | body row 2             | ...        | ...      |          |
   +------------------------+------------+----------+----------+

*Simple tables* (ref) are easier to write, but limited: they must
contain more than one row, and the first column cannot contain
multiple lines.  They look like this:

   =====  =====  =======
   A      B      A and B
   =====  =====  =======
   False  False  False
   True   False  False
   False  True   False
   True   True   True
   =====  =====  =======


Hyperlinks
==========


External links
--------------

Use ```Link text <http://example.com/>`_`` for inline web links.  If
the link text should be the web address, you don't need special markup
at all, the parser finds links and mail addresses in ordinary text.

You can also separate the link and the target definition (ref), like
this:

   This is a paragraph that contains `a link`_.

   .. _a link: http://example.com/


Internal links
--------------

Internal linking is done via a special reST role provided by Sphinx,
see the section on specific markup, *Cross-referencing arbitrary
locations*.


Sections
========

Section headers (ref) are created by underlining (and optionally
overlining) the section title with a punctuation character, at least
as long as the text:

   =================
   This is a heading
   =================

Normally, there are no heading levels assigned to certain characters
as the structure is determined from the succession of headings.
However, for the Python documentation, this convention is used which
you may follow:

* ``#`` with overline, for parts

* ``*`` with overline, for chapters

* ``=``, for sections

* ``-``, for subsections

* ``^``, for subsubsections

* ``"``, for paragraphs

Of course, you are free to use your own marker characters (see the
reST documentation), and use a deeper nesting level, but keep in mind
that most target formats (HTML, LaTeX) have a limited supported
nesting depth.


Explicit Markup
===============

"Explicit markup" (ref) is used in reST for most constructs that need
special handling, such as footnotes, specially-highlighted paragraphs,
comments, and generic directives.

An explicit markup block begins with a line starting with ``..``
followed by whitespace and is terminated by the next paragraph at the
same level of indentation.  (There needs to be a blank line between
explicit markup and normal paragraphs.  This may all sound a bit
complicated, but it is intuitive enough when you write it.)


Directives
==========

A directive (ref) is a generic block of explicit markup. Besides
roles, it is one of the extension mechanisms of reST, and Sphinx makes
heavy use of it.

Docutils supports the following directives:

* Admonitions: attention, caution, danger, error, hint, important,
  note, tip, warning and the generic admonition. (Most themes style
  only "note" and "warning" specially.)

* Images:

  * image (see also Images below)

  * figure (an image with caption and optional legend)

* Additional body elements:

  * contents (a local, i.e. for the current file only, table of
    contents)

  * container (a container with a custom class, useful to generate an
    outer ``<div>`` in HTML)

  * rubric (a heading without relation to the document sectioning)

  * topic, sidebar (special highlighted body elements)

  * parsed-literal (literal block that supports inline markup)

  * epigraph (a block quote with optional attribution line)

  * highlights, pull-quote (block quotes with their own class
    attribute)

  * compound (a compound paragraph)

* Special tables:

  * table (a table with title)

  * csv-table (a table generated from comma-separated values)

  * list-table (a table generated from a list of lists)

* Special directives:

  * raw (include raw target-format markup)

  * include (include reStructuredText from another file) -- in Sphinx,
    when given an absolute include file path, this directive takes it
    as relative to the source directory

  * class (assign a class attribute to the next element) [1]

* HTML specifics:

  * meta (generation of HTML ``<meta>`` tags)

  * title (override document title)

* Influencing markup:

  * default-role (set a new default role)

  * role (create a new role)

  Since these are only per-file, better use Sphinx' facilities for
  setting the ``default_role``.

Do *not* use the directives sectnum, header and footer.

Directives added by Sphinx are described in *Sphinx Markup
Constructs*.

Basically, a directive consists of a name, arguments, options and
content. (Keep this terminology in mind, it is used in the next
chapter describing custom directives.)  Looking at this example,

   .. function:: foo(x)
                 foo(y, z)
      :module: some.module.name

      Return a line of text input from the user.

``function`` is the directive name.  It is given two arguments here,
the remainder of the first line and the second line, as well as one
option ``module`` (as you can see, options are given in the lines
immediately following the arguments and indicated by the colons).
Options must be indented to the same level as the directive content.

The directive content follows after a blank line and is indented
relative to the directive start.


Images
======

reST supports an image directive (ref), used like so:

   .. image:: gnu.png
      (options)

When used within Sphinx, the file name given (here ``gnu.png``) must
either be relative to the source file, or absolute which means that
they are relative to the top source directory.  For example, the file
``sketch/spam.rst`` could refer to the image ``images/spam.png`` as
``../images/spam.png`` or ``/images/spam.png``.

Sphinx will automatically copy image files over to a subdirectory of
the output directory on building (e.g. the ``_static`` directory for
HTML output.)

Interpretation of image size options (``width`` and ``height``) is as
follows: if the size has no unit or the unit is pixels, the given size
will only be respected for output channels that support pixels (i.e.
not in LaTeX output). Other units (like ``pt`` for points) will be
used for HTML and LaTeX output.

Sphinx extends the standard docutils behavior by allowing an asterisk
for the extension:

   .. image:: gnu.*

Sphinx then searches for all images matching the provided pattern and
determines their type.  Each builder then chooses the best image out
of these candidates. For instance, if the file name ``gnu.*`` was
given and two files ``gnu.pdf`` and ``gnu.png`` existed in the source
tree, the LaTeX builder would choose the former, while the HTML
builder would prefer the latter.

Changed in version 0.4: Added the support for file names ending in an
asterisk.

Changed in version 0.6: Image paths can now be absolute.


Footnotes
=========

For footnotes (ref), use ``[#name]_`` to mark the footnote location,
and add the footnote body at the bottom of the document after a
"Footnotes" rubric heading, like so:

   Lorem ipsum [#f1]_ dolor sit amet ... [#f2]_

   .. rubric:: Footnotes

   .. [#f1] Text of the first footnote.
   .. [#f2] Text of the second footnote.

You can also explicitly number the footnotes (``[1]_``) or use auto-
numbered footnotes without names (``[#]_``).


Citations
=========

Standard reST citations (ref) are supported, with the additional
feature that they are "global", i.e. all citations can be referenced
from all files.  Use them like so:

   Lorem ipsum [Ref]_ dolor sit amet.

   .. [Ref] Book or article reference, URL or whatever.

Citation usage is similar to footnote usage, but with a label that is
not numeric or begins with ``#``.


Substitutions
=============

reST supports "substitutions" (ref), which are pieces of text and/or
markup referred to in the text by ``|name|``.  They are defined like
footnotes with explicit markup blocks, like this:

   .. |name| replace:: replacement *text*

or this:

   .. |caution| image:: warning.png
                :alt: Warning!

See the reST reference for substitutions for details.

If you want to use some substitutions for all documents, put them into
``rst_prolog`` or put them into a separate file and include it into
all documents you want to use them in, using the ``include``
directive.  (Be sure to give the include file a file name extension
differing from that of other source files, to avoid Sphinx finding it
as a standalone document.)

Sphinx defines some default substitutions, see *Substitutions*.


Comments
========

Every explicit markup block which isn't a valid markup construct (like
the footnotes above) is regarded as a comment (ref).  For example:

   .. This is a comment.

You can indent text after a comment start to form multiline comments:

   ..
      This whole indented block
      is a comment.

      Still in the comment.


Source encoding
===============

Since the easiest way to include special characters like em dashes or
copyright signs in reST is to directly write them as Unicode
characters, one has to specify an encoding.  Sphinx assumes source
files to be encoded in UTF-8 by default; you can change this with the
``source_encoding`` config value.


Gotchas
=======

There are some problems one commonly runs into while authoring reST
documents:

* **Separation of inline markup:** As said above, inline markup spans
  must be separated from the surrounding text by non-word characters,
  you have to use a backslash-escaped space to get around that.  See
  the reference for the details.

* **No nested inline markup:** Something like ``*see :func:`foo`*`` is
  not possible.

-[ Footnotes ]-

[1] When the default domain contains a ``class`` directive, this
    directive will be shadowed.  Therefore, Sphinx re-exports it as
    ``rst-class``.
