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doc.tex
\documentclass{howto}
\usepackage{ltxmarkup}
\title{Documenting Python}
\input{boilerplate}
% Now override the stuff that includes author information;
% Guido did *not* write this one!
\author{Fred L. Drake, Jr.}
\authoraddress{
BeOpen PythonLabs \\
E-mail: \email{fdrake@beopen.com}
}
\begin{document}
\maketitle
\begin{abstract}
\noindent
The Python language has a substantial body of
documentation, much of it contributed by various authors. The markup
used for the Python documentation is based on \LaTeX{} and requires a
significant set of macros written specifically for documenting Python.
This document describes the macros introduced to support Python
documentation and how they should be used to support a wide range of
output formats.
This document describes the document classes and special markup used
in the Python documentation. Authors may use this guide, in
conjunction with the template files provided with the
distribution, to create or maintain whole documents or sections.
\end{abstract}
\tableofcontents
\section{Introduction}
Python's documentation has long been considered to be good for a
free programming language. There are a number of reasons for this,
the most important being the early commitment of Python's creator,
Guido van Rossum, to providing documentation on the language and its
libraries, and the continuing involvement of the user community in
providing assistance for creating and maintaining documentation.
The involvement of the community takes many forms, from authoring to
bug reports to just plain complaining when the documentation could
be more complete or easier to use. All of these forms of input from
the community have proved useful during the time I've been involved
in maintaining the documentation.
This document is aimed at authors and potential authors of
documentation for Python. More specifically, it is for people
contributing to the standard documentation and developing additional
documents using the same tools as the standard documents. This
guide will be less useful for authors using the Python documentation
tools for topics other than Python, and less useful still for
authors not using the tools at all.
The material in this guide is intended to assist authors using the
Python documentation tools. It includes information on the source
distribution of the standard documentation, a discussion of the
document types, reference material on the markup defined in the
document classes, a list of the external tools needed for processing
documents, and reference material on the tools provided with the
documentation resources. At the end, there is also a section
discussing future directions for the Python documentation and where
to turn for more information.
\section{Directory Structure}
The source distribution for the standard Python documentation
contains a large number of directories. While third-party documents
do not need to be placed into this structure or need to be placed
within a similar structure, it can be helpful to know where to look
for examples and tools when developing new documents using the
Python documentation tools. This section describes this directory
structure.
The documentation sources are usually placed within the Python
source distribution as the top-level directory \file{Doc/}, but
are not dependent on the Python source distribution in any way.
The \file{Doc/} directory contains a few files and several
subdirectories. The files are mostly self-explanatory, including a
\file{README} and a \file{Makefile}. The directories fall into
three categories:
\begin{definitions}
\term{Document Sources}
The \LaTeX{} sources for each document are placed in a
separate directory. These directories are given short
names which vaguely indicate the document in each:
\begin{tableii}{p{.75in}|p{3in}}{filenq}{Directory}{Document Title}
\lineii{api/}
{\citetitle[../api/api.html]{The Python/C API}}
\lineii{dist/}
{\citetitle[../dist/dist.html]{Distributing Python Modules}}
\lineii{doc/}
{\citetitle[../doc/doc.html]{Documenting Python}}
\lineii{ext/}
{\citetitle[../ext/ext.html]{Extending and Embedding the Python Interpreter}}
\lineii{inst/}
{\citetitle[../inst/inst.html]{Installing Python Modules}}
\lineii{lib/}
{\citetitle[../lib/lib.html]{Python Library Reference}}
\lineii{mac/}
{\citetitle[../mac/mac.html]{Macintosh Module Reference}}
\lineii{ref/}
{\citetitle[../ref/ref.html]{Python Reference Manual}}
\lineii{tut/}
{\citetitle[../tut/tut.html]{Python Tutorial}}
\end{tableii}
\term{Format-Specific Output}
Most output formats have a directory which contains a
\file{Makefile} which controls the generation of that format
and provides storage for the formatted documents. The only
variations within this category are the Portable Document
Format (PDF) and PostScript versions are placed in the
directories \file{paper-a4/} and \file{paper-letter/} (this
causes all the temporary files created by \LaTeX{} to be kept
in the same place for each paper size, where they can be more
easily ignored).
\begin{tableii}{p{.75in}|p{3in}}{filenq}{Directory}{Output Formats}
\lineii{html/}{HTML output}
\lineii{info/}{GNU info output}
\lineii{paper-a4/}{PDF and PostScript, A4 paper}
\lineii{paper-letter/}{PDF and PostScript, US-Letter paper}
\end{tableii}
\term{Supplemental Files}
Some additional directories are used to store supplemental
files used for the various processes. Directories are
included for the shared \LaTeX{} document classes, the
\LaTeX2HTML support, template files for various document
components, and the scripts used to perform various steps in
the formatting processes.
\begin{tableii}{p{.75in}|p{3in}}{filenq}{Directory}{Contents}
\lineii{perl/}{Support for \LaTeX2HTML processing}
\lineii{templates/}{Example files for source documents}
\lineii{texinputs/}{Style implementation for \LaTeX}
\lineii{tools/}{Custom processing scripts}
\end{tableii}
\end{definitions}
\section{\LaTeX{} Primer \label{latex-primer}}
This section is a brief introduction to \LaTeX{} concepts and
syntax, to provide authors enough information to author documents
productively without having to become ``\TeX{}nicians.''
Perhaps the most important concept to keep in mind while marking up
Python documentation is that while \TeX{} is unstructured, \LaTeX{} was
designed as a layer on top of \TeX{} which specifically supports
structured markup. The Python-specific markup is intended to extend
the structure provided by standard \LaTeX{} document classes to
support additional information specific to Python.
\LaTeX{} documents contain two parts: the preamble and the body.
The preamble is used to specify certain metadata about the document
itself, such as the title, the list of authors, the date, and the
\emph{class} the document belongs to. Additional information used
to control index generation and the use of bibliographic databases
can also be placed in the preamble. For most authors, the preamble
can be most easily created by copying it from an existing document
and modifying a few key pieces of information.
The \dfn{class} of a document is used to place a document within a
broad category of documents and set some fundamental formatting
properties. For Python documentation, two classes are used: the
\code{manual} class and the \code{howto} class. These classes also
define the additional markup used to document Python concepts and
structures. Specific information about these classes is provided in
section \ref{classes}, ``Document Classes,'' below. The first thing
in the preamble is the declaration of the document's class.
After the class declaration, a number of \emph{macros} are used to
provide further information about the document and setup any
additional markup that is needed. No output is generated from the
preamble; it is an error to include free text in the preamble
because it would cause output.
The document body follows the preamble. This contains all the
printed components of the document marked up structurally.
XXX This section will discuss what the markup looks like, and
explain the difference between an environment and a macro.
\section{Document Classes \label{classes}}
Two \LaTeX{} document classes are defined specifically for use with
the Python documentation. The \code{manual} class is for large
documents which are sectioned into chapters, and the \code{howto}
class is for smaller documents.
The \code{manual} documents are larger and are used for most of the
standard documents. This document class is based on the standard
\LaTeX{} \code{report} class and is formatted very much like a long
technical report. The \citetitle[../ref/ref.html]{Python Reference
Manual} is a good example of a \code{manual} document, and the
\citetitle[../lib/lib.html]{Python Library Reference} is a large
example.
The \code{howto} documents are shorter, and don't have the large
structure of the \code{manual} documents. This class is based on
the standard \LaTeX{} \code{article} class and is formatted somewhat
like the Linux Documentation Project's ``HOWTO'' series as done
originally using the LinuxDoc software. The original intent for the
document class was that it serve a similar role as the LDP's HOWTO
series, but the applicability of the class turns out to be somewhat
broader. This class is used for ``how-to'' documents (this
document is an example) and for shorter reference manuals for small,
fairly cohesive module libraries. Examples of the later use include
the standard \citetitle[../mac/mac.html]{Macintosh Library Modules}
and
\citetitle[http://starship.python.net/crew/fdrake/manuals/krb5py/krb5py.html]{Using
Kerberos from Python}, which contains reference material for an
extension package. These documents are roughly equivalent to a
single chapter from a larger work.
\section{Special Markup Constructs}
The Python document classes define a lot of new environments and
macros. This section contains the reference material for these
facilities.
\subsection{Markup for the Preamble \label{preamble-info}}
\begin{macrodesc}{release}{\p{ver}}
Set the version number for the software described in the
document.
\end{macrodesc}
\begin{macrodesc}{setshortversion}{\p{sver}}
Specify the ``short'' version number of the documented software
to be \var{sver}.
\end{macrodesc}
\subsection{Meta-information Markup \label{meta-info}}
\begin{macrodesc}{sectionauthor}{\p{author}\p{email}}
Identifies the author of the current section. \var{author}
should be the author's name such that it can be used for
presentation (though it isn't), and \var{email} should be the
author's email address. The domain name portion of
the address should be lower case.
No presentation is generated from this markup, but it is used to
help keep track of contributions.
\end{macrodesc}
\subsection{Information Units \label{info-units}}
XXX Explain terminology, or come up with something more ``lay.''
There are a number of environments used to describe specific
features provided by modules. Each environment requires
parameters needed to provide basic information about what is being
described, and the environment content should be the description.
Most of these environments make entries in the general index (if
one is being produced for the document); if no index entry is
desired, non-indexing variants are available for many of these
environments. The environments have names of the form
\code{\var{feature}desc}, and the non-indexing variants are named
\code{\var{feature}descni}. The available variants are explicitly
included in the list below.
For each of these environments, the first parameter, \var{name},
provides the name by which the feature is accessed.
Environments which describe features of objects within a module,
such as object methods or data attributes, allow an optional
\var{type name} parameter. When the feature is an attribute of
class instances, \var{type name} only needs to be given if the
class was not the most recently described class in the module; the
\var{name} value from the most recent \env{classdesc} is implied.
For features of built-in or extension types, the \var{type name}
value should always be provided. Another special case includes
methods and members of general ``protocols,'' such as the
formatter and writer protocols described for the
\module{formatter} module: these may be documented without any
specific implementation classes, and will always require the
\var{type name} parameter to be provided.
\begin{envdesc}{cfuncdesc}{\p{type}\p{name}\p{args}}
Environment used to described a C function. The \var{type}
should be specified as a \keyword{typedef} name, \code{struct
\var{tag}}, or the name of a primitive type. If it is a pointer
type, the trailing asterisk should not be preceded by a space.
\var{name} should be the name of the function (or function-like
pre-processor macro), and \var{args} should give the types and
names of the parameters. The names need to be given so they may
be used in the description.
\end{envdesc}
\begin{envdesc}{ctypedesc}{\op{tag}\p{name}}
Environment used to described a C type. The \var{name}
parameter should be the \keyword{typedef} name. If the type is
defined as a \keyword{struct} without a \keyword{typedef},
\var{name} should have the form \code{struct \var{tag}}.
\var{name} will be added to the index unless \var{tag} is
provided, in which case \var{tag} will be used instead.
\var{tag} should not be used for a \keyword{typedef} name.
\end{envdesc}
\begin{envdesc}{cvardesc}{\p{type}\p{name}}
Description of a global C variable. \var{type} should be the
\keyword{typedef} name, \code{struct \var{tag}}, or the name of
a primitive type. If variable has a pointer type, the trailing
asterisk should \emph{not} be preceded by a space.
\end{envdesc}
\begin{envdesc}{datadesc}{\p{name}}
This environment is used to document global data in a module,
including both variables and values used as ``defined
constants.'' Class and object attributes are not documented
using this environment.
\end{envdesc}
\begin{envdesc}{datadescni}{\p{name}}
Like \env{datadesc}, but without creating any index entries.
\end{envdesc}
\begin{envdesc}{excdesc}{\p{name}}
Describe an exception. This may be either a string exception or
a class exception.
\end{envdesc}
\begin{envdesc}{funcdesc}{\p{name}\p{parameters}}
Describe a module-level function. \var{parameters} should
not include the parentheses used in the call syntax. Object
methods are not documented using this environment. Bound object
methods placed in the module namespace as part of the public
interface of the module are documented using this, as they are
equivalent to normal functions for most purposes.
The description should include information about the parameters
required and how they are used (especially whether mutable
objects passed as parameters are modified), side effects, and
possible exceptions. A small example may be provided.
\end{envdesc}
\begin{envdesc}{funcdescni}{\p{name}\p{parameters}}
Like \env{funcdesc}, but without creating any index entries.
\end{envdesc}
\begin{envdesc}{classdesc}{\p{name}\p{constructor parameters}}
Describe a class and its constructor. \var{constructor
parameters} should not include the \var{self} parameter or
the parentheses used in the call syntax.
\end{envdesc}
\begin{envdesc}{memberdesc}{\op{type name}\p{name}}
Describe an object data attribute. The description should
include information about the type of the data to be expected
and whether it may be changed directly.
\end{envdesc}
\begin{envdesc}{memberdescni}{\op{type name}\p{name}}
Like \env{memberdesc}, but without creating any index entries.
\end{envdesc}
\begin{envdesc}{methoddesc}{\op{type name}\p{name}\p{parameters}}
Describe an object method. \var{parameters} should not include
the \var{self} parameter or the parentheses used in the call
syntax. The description should include similar information to
that described for \env{funcdesc}.
\end{envdesc}
\begin{envdesc}{methoddescni}{\op{type name}\p{name}\p{parameters}}
Like \env{methoddesc}, but without creating any index entries.
\end{envdesc}
\subsection{Showing Code Examples}
Examples of Python source code or interactive sessions are
represented as \env{verbatim} environments. This environment
is a standard part of \LaTeX{}. It is important to only use
spaces for indentation in code examples since \TeX{} drops tabs
instead of converting them to spaces.
Representing an interactive session requires including the prompts
and output along with the Python code. No special markup is
required for interactive sessions.
Within the \env{verbatim} environment, characters special to
\LaTeX{} do not need to be specially marked in any way. The entire
example will be presented in a monospaced font; no attempt at
``pretty-printing'' is made, as the environment must work for
non-Python code and non-code displays.
The Python Documentation Special Interest Group has discussed a
number of approaches to creating pretty-printed code displays and
interactive sessions; see the Doc-SIG area on the Python Web site
for more information on this topic.
\subsection{Inline Markup}
The macros described in this section are used to mark just about
anything interesting in the document text. They may be used in
headings (though anything involving hyperlinks should be avoided
there) as well as in the body text.
\begin{macrodesc}{bfcode}{\p{text}}
Like \macro{code}, but also makes the font bold-face.
\end{macrodesc}
\begin{macrodesc}{cdata}{\p{name}}
The name of a C-language variable.
\end{macrodesc}
\begin{macrodesc}{cfunction}{\p{name}}
The name of a C-language function. \var{name} should include the
function name and the trailing parentheses.
\end{macrodesc}
\begin{macrodesc}{character}{\p{char}}
A character when discussing the character rather than a one-byte
string value. The character will be typeset as with \macro{samp}.
\end{macrodesc}
\begin{macrodesc}{citetitle}{\op{url}\p{title}}
A title for a referenced publication. If \var{url} is specified,
the title will be made into a hyperlink when formatted as HTML.
\end{macrodesc}
\begin{macrodesc}{class}{\p{name}}
A class name; a dotted name may be used.
\end{macrodesc}
\begin{macrodesc}{code}{\p{text}}
A short code fragment or literal constant value. Typically, it
should not include any spaces since no quotation marks are
added.
\end{macrodesc}
\begin{macrodesc}{constant}{\p{name}}
The name of a ``defined'' constant. This may be a C-language
\code{\#define} or a Python variable that is not intended to be
changed.
\end{macrodesc}
\begin{macrodesc}{ctype}{\p{name}}
The name of a C \keyword{typedef} or structure. For structures
defined without a \keyword{typedef}, use \code{\e ctype\{struct
struct_tag\}} to make it clear that the \keyword{struct} is
required.
\end{macrodesc}
\begin{macrodesc}{deprecated}{\p{version}\p{what to do}}
Declare whatever is being described as being deprecated starting
with release \var{version}. The text given as \var{what to do}
should recommend something to use instead.
\end{macrodesc}
\begin{macrodesc}{dfn}{\p{term}}
Mark the defining instance of \var{term} in the text. (No index
entries are generated.)
\end{macrodesc}
\begin{macrodesc}{e}{}
Produces a backslash. This is convenient in \macro{code} and
similar macros, and is only defined there. To create a
backslash in ordinary text (such as the contents of the
\macro{file} macro), use the standard \macro{textbackslash} macro.
\end{macrodesc}
\begin{macrodesc}{email}{\p{address}}
An email address. Note that this is \emph{not} hyperlinked in
any of the possible output formats. The domain name portion of
the address should be lower case.
\end{macrodesc}
\begin{macrodesc}{emph}{\p{text}}
Emphasized text; this will be presented in an italic font.
\end{macrodesc}
\begin{macrodesc}{envvar}{\p{name}}
An environment variable. Index entries are generated.
\end{macrodesc}
\begin{macrodesc}{exception}{\p{name}}
The name of an exception. A dotted name may be used.
\end{macrodesc}
\begin{macrodesc}{file}{\p{file or dir}}
The name of a file or directory. In the PDF and PostScript
outputs, single quotes and a font change are used to indicate
the file name, but no quotes are used in the HTML output.
\strong{Warning:} The \macro{file} macro cannot be used in the
content of a section title due to processing limitations.
\end{macrodesc}
\begin{macrodesc}{filenq}{\p{file or dir}}
Like \macro{file}, but single quotes are never used. This can
be used in conjunction with tables if a column will only contain
file or directory names.
\strong{Warning:} The \macro{filenq} macro cannot be used in the
content of a section title due to processing limitations.
\end{macrodesc}
\begin{macrodesc}{function}{\p{name}}
The name of a Python function; dotted names may be used.
\end{macrodesc}
\begin{macrodesc}{kbd}{\p{key sequence}}
Mark a sequence of keystrokes. What form \var{key sequence}
takes may depend on platform- or application-specific
conventions. For example, an \program{xemacs} key sequence
may be marked like \code{\e kbd\{C-x C-f\}}.
\end{macrodesc}
\begin{macrodesc}{keyword}{\p{name}}
The name of a keyword in a programming language.
\end{macrodesc}
\begin{macrodesc}{makevar}{\p{name}}
The name of a \program{make} variable.
\end{macrodesc}
\begin{macrodesc}{manpage}{\p{name}\p{section}}
A reference to a \UNIX{} manual page.
\end{macrodesc}
\begin{macrodesc}{member}{\p{name}}
The name of a data attribute of an object.
\end{macrodesc}
\begin{macrodesc}{method}{\p{name}}
The name of a method of an object. \var{name} should include the
method name and the trailing parentheses. A dotted name may be
used.
\end{macrodesc}
\begin{macrodesc}{mimetype}{\p{name}}
The name of a MIME type.
\end{macrodesc}
\begin{macrodesc}{module}{\p{name}}
The name of a module; a dotted name may be used. This should
also be used for package names.
\end{macrodesc}
\begin{macrodesc}{newsgroup}{\p{name}}
The name of a USENET newsgroup.
\end{macrodesc}
\begin{macrodesc}{program}{\p{name}}
The name of an executable program. This may differ from the
file name for the executable for some platforms. In particular,
the \file{.exe} (or other) extension should be omitted for DOS
and Windows programs.
\end{macrodesc}
\begin{macrodesc}{programopt}{\p{option}}
A command-line option to an executable program. Use this only
for ``shot'' options, and include the leading hyphen.
\end{macrodesc}
\begin{macrodesc}{longprogramopt}{\p{option}}
A long command-line option to an executable program. This
should only be used for long option names which will be prefixed
by two hyphens; the hyphens should not be provided as part of
\var{option}.
\end{macrodesc}
\begin{macrodesc}{pep}{\p{number}}
A reference to a Python Enhancement Proposal. This generates
appropriate index entries. The text \samp{PEP \var{number}} is
generated; in the HTML output, this text is a hyperlink to an
online copy of the specified PEP.
\end{macrodesc}
\begin{macrodesc}{refmodule}{\op{key}\p{name}}
Like \macro{module}, but create a hyperlink to the documentation
for the named module. Note that the corresponding
\macro{declaremodule} must be in the same document. If the
\macro{declaremodule} defines a module key different from the
module name, it must also be provided as \var{key} to the
\macro{refmodule} macro.
\end{macrodesc}
\begin{macrodesc}{regexp}{\p{string}}
Mark a regular expression.
\end{macrodesc}
\begin{macrodesc}{rfc}{\p{number}}
A reference to an Internet Request for Comments. This generates
appropriate index entries. The text \samp{RFC \var{number}} is
generated; in the HTML output, this text is a hyperlink to an
online copy of the specified RFC.
\end{macrodesc}
\begin{macrodesc}{samp}{\p{text}}
A short code sample, but possibly longer than would be given
using \macro{code}. Since quotation marks are added, spaces are
acceptable.
\end{macrodesc}
\begin{macrodesc}{shortversion}{}
The ``short'' version number of the documented software, as
specified using the \macro{setshortversion} macro in the
preamble. For Python, the short version number for a release is
the first three characters of the \code{sys.version} value. For
example, versions 2.0b1 and 2.0.1 both have a short version of
2.0. This may not apply for all packages; if
\macro{setshortversion} is not used, this produces an empty
expansion. See also the \macro{version} macro.
\end{macrodesc}
\begin{macrodesc}{strong}{\p{text}}
Strongly emphasized text; this will be presented using a bold
font.
\end{macrodesc}
\begin{macrodesc}{url}{\p{url}}
A URL (or URN). The URL will be presented as text. In the HTML
and PDF formatted versions, the URL will also be a hyperlink.
This can be used when referring to external resources. Note
that many characters are special to \LaTeX{} and this macro
does not always do the right thing. In particular, the tilde
character (\character{\~}) is mis-handled; encoding it as a
hex-sequence does work, use \samp{\%7e} in place of the tilde
character.
\end{macrodesc}
\begin{macrodesc}{var}{\p{name}}
The name of a variable or formal parameter in running text.
\end{macrodesc}
\begin{macrodesc}{version}{}
The version number of the described software, as specified using
\macro{release} in the preamble. See also the
\macro{shortversion} macro.
\end{macrodesc}
\begin{macrodesc}{versionadded}{\p{version}}
The version of Python which added the described feature to the
library or C API. This is typically added to the end of the
first paragraph of the description before any availability
notes. The location should be selected so the explanation makes
sense and may vary as needed.
\end{macrodesc}
\begin{macrodesc}{versionchanged}{\op{explanation}\p{version}}
The version of Python in which the named feature was changed in
some way (new parameters, changed side effects, etc.).
\var{explanation} should be a \emph{brief} explanation of the
change consisting of a non-capitalized sentence fragment; a
period will be appended by the formatting process.
This is typically added to the end of the first paragraph of the
description before any availability notes and after
\macro{versionadded}. The location should be selected so the
explanation makes sense and may vary as needed.
\end{macrodesc}
\subsection{Module-specific Markup}
The markup described in this section is used to provide information
about a module being documented. A typical use of this markup
appears at the top of the section used to document a module. A
typical example might look like this:
\begin{verbatim}
\section{\module{spam} ---
Access to the SPAM facility}
\declaremodule{extension}{spam}
\platform{Unix}
\modulesynopsis{Access to the SPAM facility of \UNIX{}.}
\moduleauthor{Jane Doe}{jane.doe@frobnitz.org}
\end{verbatim}
Python packages\index{packages} --- collections of modules that can
be described as a unit --- are documented using the same markup as
modules. The name for a module in a package should be typed in
``fully qualified'' form (i.e., it should include the package name).
For example, a module ``foo'' in package ``bar'' should be marked as
\samp{\e module\{bar.foo\}}, and the beginning of the reference
section would appear as:
\begin{verbatim}
\section{\module{bar.foo} ---
Module from the \module{bar} package}
\declaremodule{extension}{bar.foo}
\modulesynopsis{Nifty module from the \module{bar} package.}
\moduleauthor{Jane Doe}{jane.doe@frobnitz.org}
\end{verbatim}
Note that the name of a package is also marked using
\macro{module}.
\begin{macrodesc}{declaremodule}{\op{key}\p{type}\p{name}}
Requires two parameters: module type (\samp{standard},
\samp{builtin}, \samp{extension}, or \samp{}), and the module
name. An optional parameter should be given as the basis for the
module's ``key'' used for linking to or referencing the section.
The ``key'' should only be given if the module's name contains any
underscores, and should be the name with the underscores stripped.
Note that the \var{type} parameter must be one of the values
listed above or an error will be printed. For modules which are
contained in packages, the fully-qualified name should be given as
\var{name} parameter. This should be the first thing after the
\macro{section} used to introduce the module.
\end{macrodesc}
\begin{macrodesc}{platform}{\p{specifier}}
Specifies the portability of the module. \var{specifier} is a
comma-separated list of keys that specify what platforms the
module is available on. The keys are short identifiers;
examples that are in use include \samp{IRIX}, \samp{Mac},
\samp{Windows}, and \samp{Unix}. It is important to use a key
which has already been used when applicable. This is used to
provide annotations in the Module Index and the HTML and GNU info
output.
\end{macrodesc}
\begin{macrodesc}{modulesynopsis}{\p{text}}
The \var{text} is a short, ``one line'' description of the
module that can be used as part of the chapter introduction.
This is must be placed after \macro{declaremodule}.
The synopsis is used in building the contents of the table
inserted as the \macro{localmoduletable}. No text is
produced at the point of the markup.
\end{macrodesc}
\begin{macrodesc}{moduleauthor}{\p{name}\p{email}}
This macro is used to encode information about who authored a
module. This is currently not used to generate output, but can be
used to help determine the origin of the module.
\end{macrodesc}
\subsection{Library-level Markup}
This markup is used when describing a selection of modules. For
example, the \citetitle[../mac/mac.html]{Macintosh Library
Modules} document uses this to help provide an overview of the
modules in the collection, and many chapters in the
\citetitle[../lib/lib.html]{Python Library Reference} use it for
the same purpose.
\begin{macrodesc}{localmoduletable}{}
If a \file{.syn} file exists for the current
chapter (or for the entire document in \code{howto} documents), a
\env{synopsistable} is created with the contents loaded from the
\file{.syn} file.
\end{macrodesc}
\subsection{Table Markup}
There are three general-purpose table environments defined which
should be used whenever possible. These environments are defined
to provide tables of specific widths and some convenience for
formatting. These environments are not meant to be general
replacements for the standard \LaTeX{} table environments, but can
be used for an advantage when the documents are processed using
the tools for Python documentation processing. In particular, the
generated HTML looks good! There is also an advantage for the
eventual conversion of the documentation to SGML (see section
\ref{futures}, ``Future Directions'').
Each environment is named \env{table\var{cols}}, where \var{cols}
is the number of columns in the table specified in lower-case
Roman numerals. Within each of these environments, an additional
macro, \macro{line\var{cols}}, is defined, where \var{cols}
matches the \var{cols} value of the corresponding table
environment. These are supported for \var{cols} values of
\code{ii}, \code{iii}, and \code{iv}. These environments are all
built on top of the \env{tabular} environment. Variants based on
the \env{longtable} environment are also provided.
Note that all tables in the standard Python documentation use
vertical lines between columns, and this must be specified in the
markup for each table. A general border around the outside of the
table is not used, but would be the responsibility of the
processor; the document markup should not include an exterior
border.
The \env{longtable}-based variants of the table environments are
formatted with extra space before and after, so should only be
used on tables which are long enough that splitting over multiple
pages is reasonable; tables with fewer than twenty rows should
never by marked using the long flavors of the table environments.
The header row is repeated across the top of each part of the
table.
\begin{envdesc}{tableii}{\p{colspec}\p{col1font}\p{heading1}\p{heading2}}
Create a two-column table using the \LaTeX{} column specifier
\var{colspec}. The column specifier should indicate vertical
bars between columns as appropriate for the specific table, but
should not specify vertical bars on the outside of the table
(that is considered a stylesheet issue). The \var{col1font}
parameter is used as a stylistic treatment of the first column
of the table: the first column is presented as
\code{\e\var{col1font}\{column1\}}. To avoid treating the first
column specially, \var{col1font} may be \samp{textrm}. The
column headings are taken from the values \var{heading1} and
\var{heading2}.
\end{envdesc}
\begin{envdesc}{longtableii}{\unspecified}
Like \env{tableii}, but produces a table which may be broken
across page boundaries. The parameters are the same as for
\env{tableii}.
\end{envdesc}
\begin{macrodesc}{lineii}{\p{column1}\p{column2}}
Create a single table row within a \env{tableii} or
\env{longtableii} environment.
The text for the first column will be generated by applying the
macro named by the \var{col1font} value when the \env{tableii}
was opened.
\end{macrodesc}
\begin{envdesc}{tableiii}{\p{colspec}\p{col1font}\p{heading1}\p{heading2}\p{heading3}}
Like the \env{tableii} environment, but with a third column.
The heading for the third column is given by \var{heading3}.
\end{envdesc}
\begin{envdesc}{longtableiii}{\unspecified}
Like \env{tableiii}, but produces a table which may be broken
across page boundaries. The parameters are the same as for
\env{tableiii}.
\end{envdesc}
\begin{macrodesc}{lineiii}{\p{column1}\p{column2}\p{column3}}
Like the \macro{lineii} macro, but with a third column. The
text for the third column is given by \var{column3}.
\end{macrodesc}
\begin{envdesc}{tableiv}{\p{colspec}\p{col1font}\p{heading1}\p{heading2}\p{heading3}\p{heading4}}
Like the \env{tableiii} environment, but with a fourth column.
The heading for the fourth column is given by \var{heading4}.
\end{envdesc}
\begin{envdesc}{longtableiv}{\unspecified}
Like \env{tableiv}, but produces a table which may be broken
across page boundaries. The parameters are the same as for
\env{tableiv}.
\end{envdesc}
\begin{macrodesc}{lineiv}{\p{column1}\p{column2}\p{column3}\p{column4}}
Like the \macro{lineiii} macro, but with a fourth column. The
text for the fourth column is given by \var{column4}.
\end{macrodesc}
An additional table-like environment is \env{synopsistable}. The
table generated by this environment contains two columns, and each
row is defined by an alternate definition of
\macro{modulesynopsis}. This environment is not normally used by
authors, but is created by the \macro{localmoduletable} macro.
\subsection{Reference List Markup \label{references}}
Many sections include a list of references to module documentation
or external documents. These lists are created using the
\env{seealso} environment. This environment defines some
additional macros to support creating reference entries in a
reasonable manner.
The \env{seealso} environment is typically placed in a section
just before any sub-sections. This is done to ensure that
reference links related to the section are not hidden in a
subsection in the hypertext renditions of the documentation.
\begin{envdesc}{seealso}{}
This environment creates a ``See also:'' heading and defines the
markup used to describe individual references.
\end{envdesc}
For each of the following macros, \var{why} should be one or more
complete sentences, starting with a capital letter (unless it
starts with an identifier, which should not be modified), and
ending with the apropriate punctuation.
These macros are only defined within the content of the
\env{seealso} environment.
\begin{macrodesc}{seemodule}{\op{key}\p{name}\p{why}}
Refer to another module. \var{why} should be a brief
explanation of why the reference may be interesting. The module
name is given in \var{name}, with the link key given in
\var{key} if necessary. In the HTML and PDF conversions, the
module name will be a hyperlink to the referred-to module.
\strong{Note:} The module must be documented in the same
document (the corresponding \macro{declaremodule} is required).
\end{macrodesc}
\begin{macrodesc}{seepep}{\p{number}\p{title}\p{why}}
Refer to an Python Enhancement Proposal (PEP). \var{number}
should be the official number assigned by the PEP Editor,
\var{title} should be the human-readable title of the PEP as
found in the official copy of the document, and \var{why} should
explain what's interesting about the PEP. This should be used
to refer the reader to PEPs which specify interfaces or language
features relevant to the material in the annotated section of the
documentation.
\end{macrodesc}
\begin{macrodesc}{seerfc}{\p{number}\p{title}\p{why}}
Refer to an IETF Request for Comments (RFC). Otherwise very
similar to \macro{seepep}. This should be used
to refer the reader to PEPs which specify protocols or data
formats relevant to the material in the annotated section of the
documentation.
\end{macrodesc}
\begin{macrodesc}{seetext}{\p{text}}
Add arbitrary text \var{text} to the ``See also:'' list. This
can be used to refer to off-line materials or on-line materials
using the \macro{url} macro. This should consist of one or more
complete sentences.
\end{macrodesc}
\begin{macrodesc}{seetitle}{\op{url}\p{title}\p{why}}
Add a reference to an external document named \var{title}. If
\var{url} is given, the title is made a hyperlink in the HTML
version of the documentation, and displayed below the title in
the typeset versions of the documentation.
\end{macrodesc}
\begin{macrodesc}{seeurl}{\p{url}\p{why}}
References to specific on-line resources should be given using
the \macro{seeurl} macro. No title is associated with the
reference, but the \var{why} text may include a title marked
using the \macro{citetitle} macro.
\end{macrodesc}
\subsection{Index-generating Markup \label{indexing}}
Effective index generation for technical documents can be very
difficult, especially for someone familiar with the topic but not
the creation of indexes. Much of the difficulty arises in the
area of terminology: including the terms an expert would use for a
concept is not sufficient. Coming up with the terms that a novice
would look up is fairly difficult for an author who, typically, is
an expert in the area she is writing on.
The truly difficult aspects of index generation are not areas with
which the documentation tools can help. However, ease
of producing the index once content decisions are made is within
the scope of the tools. Markup is provided which the processing
software is able to use to generate a variety of kinds of index
entry with minimal effort. Additionally, many of the environments
described in section \ref{info-units}, ``Information Units,'' will
generate appropriate entries into the general and module indexes.
The following macro can be used to control the generation of index
data, and should be used in the document preamble:
\begin{macrodesc}{makemodindex}{}
This should be used in the document preamble if a ``Module
Index'' is desired for a document containing reference material
on many modules. This causes a data file
\code{lib\var{jobname}.idx} to be created from the
\macro{declaremodule} macros. This file can be processed by the
\program{makeindex} program to generate a file which can be
\macro{input} into the document at the desired location of the
module index.
\end{macrodesc}
There are a number of macros that are useful for adding index
entries for particular concepts, many of which are specific to
programming languages or even Python.
\begin{macrodesc}{bifuncindex}{\p{name}}
Add an index entry referring to a built-in function named
\var{name}; parentheses should not be included after
\var{name}.
\end{macrodesc}
\begin{macrodesc}{exindex}{\p{exception}}
Add a reference to an exception named \var{exception}. The
exception may be either string- or class-based.
\end{macrodesc}
\begin{macrodesc}{kwindex}{\p{keyword}}
Add a reference to a language keyword (not a keyword parameter
in a function or method call).
\end{macrodesc}
\begin{macrodesc}{obindex}{\p{object type}}
Add an index entry for a built-in object type.
\end{macrodesc}
\begin{macrodesc}{opindex}{\p{operator}}
Add a reference to an operator, such as \samp{+}.
\end{macrodesc}
\begin{macrodesc}{refmodindex}{\op{key}\p{module}}
Add an index entry for module \var{module}; if \var{module}
contains an underscore, the optional parameter \var{key} should
be provided as the same string with underscores removed. An
index entry ``\var{module} (module)'' will be generated. This
is intended for use with non-standard modules implemented in
Python.
\end{macrodesc}
\begin{macrodesc}{refexmodindex}{\op{key}\p{module}}
As for \macro{refmodindex}, but the index entry will be
``\var{module} (extension module).'' This is intended for use
with non-standard modules not implemented in Python.
\end{macrodesc}
\begin{macrodesc}{refbimodindex}{\op{key}\p{module}}
As for \macro{refmodindex}, but the index entry will be
``\var{module} (built-in module).'' This is intended for use
with standard modules not implemented in Python.
\end{macrodesc}
\begin{macrodesc}{refstmodindex}{\op{key}\p{module}}
As for \macro{refmodindex}, but the index entry will be
``\var{module} (standard module).'' This is intended for use
with standard modules implemented in Python.
\end{macrodesc}
\begin{macrodesc}{stindex}{\p{statement}}
Add an index entry for a statement type, such as \keyword{print}
or \keyword{try}/\keyword{finally}.
XXX Need better examples of difference from \macro{kwindex}.
\end{macrodesc}
Additional macros are provided which are useful for conveniently
creating general index entries which should appear at many places
in the index by rotating a list of words. These are simple macros
that simply use \macro{index} to build some number of index
entries. Index entries build using these macros contain both
primary and secondary text.
\begin{macrodesc}{indexii}{\p{word1}\p{word2}}
Build two index entries. This is exactly equivalent to using
\code{\e index\{\var{word1}!\var{word2}\}} and
\code{\e index\{\var{word2}!\var{word1}\}}.
\end{macrodesc}
\begin{macrodesc}{indexiii}{\p{word1}\p{word2}\p{word3}}
Build three index entries. This is exactly equivalent to using
\code{\e index\{\var{word1}!\var{word2} \var{word3}\}},
\code{\e index\{\var{word2}!\var{word3}, \var{word1}\}}, and
\code{\e index\{\var{word3}!\var{word1} \var{word2}\}}.
\end{macrodesc}
\begin{macrodesc}{indexiv}{\p{word1}\p{word2}\p{word3}\p{word4}}
Build four index entries. This is exactly equivalent to using
\code{\e index\{\var{word1}!\var{word2} \var{word3} \var{word4}\}},
\code{\e index\{\var{word2}!\var{word3} \var{word4}, \var{word1}\}},
\code{\e index\{\var{word3}!\var{word4}, \var{word1} \var{word2}\}},
and
\code{\e index\{\var{word4}!\var{word1} \var{word2} \var{word3}\}}.
\end{macrodesc}
\section{Special Names}
Many special names are used in the Python documentation, including
the names of operating systems, programming languages, standards
bodies, and the like. Many of these were assigned \LaTeX{} macros
at some point in the distant past, and these macros lived on long
past their usefulness. In the current markup, these entities are
not assigned any special markup, but the preferred spellings are
given here to aid authors in maintaining the consistency of
presentation in the Python documentation.
\begin{description}
\item[POSIX]
The name assigned to a particular group of standards. This is
always uppercase.
\item[Python]
The name of our favorite programming language is always
capitalized.
\item[Unicode]
The name of a character set and matching encoding. This is
always written capitalized.
\end{description}
\section{Processing Tools}
\subsection{External Tools}
Many tools are needed to be able to process the Python
documentation if all supported formats are required. This
section lists the tools used and when each is required. Consult
the \file{Doc/README} file to see if there are specific version
requirements for any of these.
\begin{description}
\item[\program{dvips}]
This program is a typical part of \TeX{} installations. It is
used to generate PostScript from the ``device independent''
\file{.dvi} files. It is needed for the conversion to
PostScript.
\item[\program{emacs}]
Emacs is the kitchen sink of programmers' editors, and a damn
fine kitchen sink it is. It also comes with some of the
processing needed to support the proper menu structures for
Texinfo documents when an info conversion is desired. This is
needed for the info conversion. Using \program{xemacs}
instead of FSF \program{emacs} may lead to instability in the
conversion, but that's because nobody seems to maintain the
Emacs Texinfo code in a portable manner.
\item[\program{latex}]
This is a world-class typesetter by Donald Knuth. It is used
for the conversion to PostScript, and is needed for the HTML
conversion as well (\LaTeX2HTML requires one of the
intermediate files it creates).
\item[\program{latex2html}]
Probably the longest Perl script anyone ever attempted to
maintain. This converts \LaTeX{} documents to HTML documents,
and does a pretty reasonable job. It is required for the
conversions to HTML and GNU info.
\item[\program{lynx}]
This is a text-mode Web browser which includes an
HTML-to-plain text conversion. This is used to convert
\code{howto} documents to text.
\item[\program{make}]
Just about any version should work for the standard documents,
but GNU \program{make} is required for the experimental
processes in \file{Doc/tools/sgmlconv/}, at least while
they're experimental.
\item[\program{makeindex}]
This is a standard program for converting \LaTeX{} index data
to a formatted index; it should be included with all \LaTeX{}
installations. It is needed for the PDF and PostScript
conversions.
\item[\program{makeinfo}]
GNU \program{makeinfo} is used to convert Texinfo documents to
GNU info files. Since Texinfo is used as an intermediate
format in the info conversion, this program is needed in that
conversion.
\item[\program{pdflatex}]
pdf\TeX{} is a relatively new variant of \TeX, and is used to
generate the PDF version of the manuals. It is typically
installed as part of most of the large \TeX{} distributions.
\program{pdflatex} is pdf\TeX{} using the \LaTeX{} format.
\item[\program{perl}]
Perl is required for \LaTeX2HTML{} and one of the scripts used
to post-process \LaTeX2HTML output, as well as the
HTML-to-Texinfo conversion. This is required for
the HTML and GNU info conversions.
\item[\program{python}]
Python is used for many of the scripts in the
\file{Doc/tools/} directory; it is required for all
conversions. This shouldn't be a problem if you're interested
in writing documentation for Python!
\end{description}
\subsection{Internal Tools}
This section describes the various scripts that are used to
implement various stages of document processing or to orchestrate
entire build sequences. Most of these tools are only useful
in the context of building the standard documentation, but some
are more general.
\begin{description}
\item[\program{mkhowto}]
This is the primary script used to format third-party
documents. It contains all the logic needed to ``get it
right.'' The proper way to use this script is to make a
symbolic link to it or run it in place; the actual script file
must be stored as part of the documentation source tree,
though it may be used to format documents outside the
tree. Use \program{mkhowto} \longprogramopt{help}
for a list of
command line options.
\program{mkhowto} can be used for both \code{howto} and
\code{manual} class documents. (For the later, be sure to get
the latest version from the Python CVS repository rather than
the version distributed in the \file{latex-1.5.2.tgz} source
archive.)
XXX Need more here.
\end{description}
\section{Future Directions \label{futures}}
The history of the Python documentation is full of changes, most of
which have been fairly small and evolutionary. There has been a
great deal of discussion about making large changes in the markup
languages and tools used to process the documentation. This section
deals with the nature of the changes and what appears to be the most
likely path of future development.
\subsection{Structured Documentation \label{structured}}
Most of the small changes to the \LaTeX{} markup have been made
with an eye to divorcing the markup from the presentation, making
both a bit more maintainable. Over the course of 1998, a large
number of changes were made with exactly this in mind; previously,
changes had been made but in a less systematic manner and with
more concern for not needing to update the existing content. The
result has been a highly structured and semantically loaded markup
language implemented in \LaTeX. With almost no basic \TeX{} or
\LaTeX{} markup in use, however, the markup syntax is about the
only evidence of \LaTeX{} in the actual document sources.
One side effect of this is that while we've been able to use
standard ``engines'' for manipulating the documents, such as
\LaTeX{} and \LaTeX2HTML, most of the actual transformations have
been created specifically for Python. The \LaTeX{} document
classes and \LaTeX2HTML support are both complete implementations
of the specific markup designed for these documents.
Combining highly customized markup with the somewhat esoteric
systems used to process the documents leads us to ask some
questions: Can we do this more easily? and, Can we do this
better? After a great deal of discussion with the community, we
have determined that actively pursuing modern structured
documentation systems is worth some investment of time.
There appear to be two real contenders in this arena: the Standard
General Markup Language (SGML), and the Extensible Markup Language
(XML). Both of these standards have advantages and disadvantages,
and many advantages are shared.
SGML offers advantages which may appeal most to authors,
especially those using ordinary text editors. There are also
additional abilities to define content models. A number of
high-quality tools with demonstrated maturity is available, but
most are not free; for those which are, portability issues remain
a problem.
The advantages of XML include the availability of a large number
of evolving tools. Unfortunately, many of the associated
standards are still evolving, and the tools will have to follow
along. This means that developing a robust tool set that uses
more than the basic XML 1.0 recommendation is not possible in the
short term. The promised availability of a wide variety of
high-quality tools which support some of the most important
related standards is not immediate. Many tools are likely to be
free.
XXX Eventual migration to SGML/XML.
\subsection{Discussion Forums \label{discussion}}
Discussion of the future of the Python documentation and related
topics takes place in the Documentation Special Interest Group, or
``Doc-SIG.'' Information on the group, including mailing list
archives and subscription information, is available at
\url{http://www.python.org/sigs/doc-sig/}. The SIG is open to all
interested parties.
Comments and bug reports on the standard documents should be sent
to \email{python-docs@python.org}. This may include comments
about formatting, content, grammatical and spelling errors, or
this document. You can also send comments on this document
directly to the author at \email{fdrake@acm.org}.
\end{document}
