initial drop of setuptools v39.1.0

Test: N/A
Bug: b/79751992
Change-Id: Iccb41bbd58f7a6af510957966c5d893c2875e4ee
diff --git a/docs/setuptools.txt b/docs/setuptools.txt
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+==================================================
+Building and Distributing Packages with Setuptools
+==================================================
+
+``Setuptools`` is a collection of enhancements to the Python ``distutils``
+that allow developers to more easily build and
+distribute Python packages, especially ones that have dependencies on other
+packages.
+
+Packages built and distributed using ``setuptools`` look to the user like
+ordinary Python packages based on the ``distutils``.  Your users don't need to
+install or even know about setuptools in order to use them, and you don't
+have to include the entire setuptools package in your distributions.  By
+including just a single `bootstrap module`_ (a 12K .py file), your package will
+automatically download and install ``setuptools`` if the user is building your
+package from source and doesn't have a suitable version already installed.
+
+.. _bootstrap module: https://bootstrap.pypa.io/ez_setup.py
+
+Feature Highlights:
+
+* Automatically find/download/install/upgrade dependencies at build time using
+  the `EasyInstall tool <easy_install.html>`_,
+  which supports downloading via HTTP, FTP, Subversion, and SourceForge, and
+  automatically scans web pages linked from PyPI to find download links.  (It's
+  the closest thing to CPAN currently available for Python.)
+
+* Create `Python Eggs <http://peak.telecommunity.com/DevCenter/PythonEggs>`_ -
+  a single-file importable distribution format
+
+* Enhanced support for accessing data files hosted in zipped packages.
+
+* Automatically include all packages in your source tree, without listing them
+  individually in setup.py
+
+* Automatically include all relevant files in your source distributions,
+  without needing to create a ``MANIFEST.in`` file, and without having to force
+  regeneration of the ``MANIFEST`` file when your source tree changes.
+
+* Automatically generate wrapper scripts or Windows (console and GUI) .exe
+  files for any number of "main" functions in your project.  (Note: this is not
+  a py2exe replacement; the .exe files rely on the local Python installation.)
+
+* Transparent Pyrex support, so that your setup.py can list ``.pyx`` files and
+  still work even when the end-user doesn't have Pyrex installed (as long as
+  you include the Pyrex-generated C in your source distribution)
+
+* Command aliases - create project-specific, per-user, or site-wide shortcut
+  names for commonly used commands and options
+
+* PyPI upload support - upload your source distributions and eggs to PyPI
+
+* Deploy your project in "development mode", such that it's available on
+  ``sys.path``, yet can still be edited directly from its source checkout.
+
+* Easily extend the distutils with new commands or ``setup()`` arguments, and
+  distribute/reuse your extensions for multiple projects, without copying code.
+
+* Create extensible applications and frameworks that automatically discover
+  extensions, using simple "entry points" declared in a project's setup script.
+
+.. contents:: **Table of Contents**
+
+.. _ez_setup.py: `bootstrap module`_
+
+
+-----------------
+Developer's Guide
+-----------------
+
+
+Installing ``setuptools``
+=========================
+
+Please follow the `EasyInstall Installation Instructions`_ to install the
+current stable version of setuptools.  In particular, be sure to read the
+section on `Custom Installation Locations`_ if you are installing anywhere
+other than Python's ``site-packages`` directory.
+
+.. _EasyInstall Installation Instructions: easy_install.html#installation-instructions
+
+.. _Custom Installation Locations: easy_install.html#custom-installation-locations
+
+If you want the current in-development version of setuptools, you should first
+install a stable version, and then run::
+
+    ez_setup.py setuptools==dev
+
+This will download and install the latest development (i.e. unstable) version
+of setuptools from the Python Subversion sandbox.
+
+
+Basic Use
+=========
+
+For basic use of setuptools, just import things from setuptools instead of
+the distutils.  Here's a minimal setup script using setuptools::
+
+    from setuptools import setup, find_packages
+    setup(
+        name="HelloWorld",
+        version="0.1",
+        packages=find_packages(),
+    )
+
+As you can see, it doesn't take much to use setuptools in a project.
+Run that script in your project folder, alongside the Python packages
+you have developed.
+
+Invoke that script to produce eggs, upload to
+PyPI, and automatically include all packages in the directory where the
+setup.py lives.  See the `Command Reference`_ section below to see what
+commands you can give to this setup script. For example,
+to produce a source distribution, simply invoke::
+
+    python setup.py sdist
+
+Of course, before you release your project to PyPI, you'll want to add a bit
+more information to your setup script to help people find or learn about your
+project.  And maybe your project will have grown by then to include a few
+dependencies, and perhaps some data files and scripts::
+
+    from setuptools import setup, find_packages
+    setup(
+        name="HelloWorld",
+        version="0.1",
+        packages=find_packages(),
+        scripts=['say_hello.py'],
+
+        # Project uses reStructuredText, so ensure that the docutils get
+        # installed or upgraded on the target machine
+        install_requires=['docutils>=0.3'],
+
+        package_data={
+            # If any package contains *.txt or *.rst files, include them:
+            '': ['*.txt', '*.rst'],
+            # And include any *.msg files found in the 'hello' package, too:
+            'hello': ['*.msg'],
+        },
+
+        # metadata for upload to PyPI
+        author="Me",
+        author_email="me@example.com",
+        description="This is an Example Package",
+        license="PSF",
+        keywords="hello world example examples",
+        url="http://example.com/HelloWorld/",   # project home page, if any
+        project_urls={
+            "Bug Tracker": "https://bugs.example.com/HelloWorld/",
+            "Documentation": "https://docs.example.com/HelloWorld/",
+            "Source Code": "https://code.example.com/HelloWorld/",
+        }
+
+        # could also include long_description, download_url, classifiers, etc.
+    )
+
+In the sections that follow, we'll explain what most of these ``setup()``
+arguments do (except for the metadata ones), and the various ways you might use
+them in your own project(s).
+
+
+Specifying Your Project's Version
+---------------------------------
+
+Setuptools can work well with most versioning schemes; there are, however, a
+few special things to watch out for, in order to ensure that setuptools and
+EasyInstall can always tell what version of your package is newer than another
+version.  Knowing these things will also help you correctly specify what
+versions of other projects your project depends on.
+
+A version consists of an alternating series of release numbers and pre-release
+or post-release tags.  A release number is a series of digits punctuated by
+dots, such as ``2.4`` or ``0.5``.  Each series of digits is treated
+numerically, so releases ``2.1`` and ``2.1.0`` are different ways to spell the
+same release number, denoting the first subrelease of release 2.  But  ``2.10``
+is the *tenth* subrelease of release 2, and so is a different and newer release
+from ``2.1`` or ``2.1.0``.  Leading zeros within a series of digits are also
+ignored, so ``2.01`` is the same as ``2.1``, and different from ``2.0.1``.
+
+Following a release number, you can have either a pre-release or post-release
+tag.  Pre-release tags make a version be considered *older* than the version
+they are appended to.  So, revision ``2.4`` is *newer* than revision ``2.4c1``,
+which in turn is newer than ``2.4b1`` or ``2.4a1``.  Postrelease tags make
+a version be considered *newer* than the version they are appended to.  So,
+revisions like ``2.4-1`` and ``2.4pl3`` are newer than ``2.4``, but are *older*
+than ``2.4.1`` (which has a higher release number).
+
+A pre-release tag is a series of letters that are alphabetically before
+"final".  Some examples of prerelease tags would include ``alpha``, ``beta``,
+``a``, ``c``, ``dev``, and so on.  You do not have to place a dot or dash
+before the prerelease tag if it's immediately after a number, but it's okay to
+do so if you prefer.  Thus, ``2.4c1`` and ``2.4.c1`` and ``2.4-c1`` all
+represent release candidate 1 of version ``2.4``, and are treated as identical
+by setuptools.
+
+In addition, there are three special prerelease tags that are treated as if
+they were the letter ``c``: ``pre``, ``preview``, and ``rc``.  So, version
+``2.4rc1``, ``2.4pre1`` and ``2.4preview1`` are all the exact same version as
+``2.4c1``, and are treated as identical by setuptools.
+
+A post-release tag is either a series of letters that are alphabetically
+greater than or equal to "final", or a dash (``-``).  Post-release tags are
+generally used to separate patch numbers, port numbers, build numbers, revision
+numbers, or date stamps from the release number.  For example, the version
+``2.4-r1263`` might denote Subversion revision 1263 of a post-release patch of
+version ``2.4``.  Or you might use ``2.4-20051127`` to denote a date-stamped
+post-release.
+
+Notice that after each pre or post-release tag, you are free to place another
+release number, followed again by more pre- or post-release tags.  For example,
+``0.6a9.dev-r41475`` could denote Subversion revision 41475 of the in-
+development version of the ninth alpha of release 0.6.  Notice that ``dev`` is
+a pre-release tag, so this version is a *lower* version number than ``0.6a9``,
+which would be the actual ninth alpha of release 0.6.  But the ``-r41475`` is
+a post-release tag, so this version is *newer* than ``0.6a9.dev``.
+
+For the most part, setuptools' interpretation of version numbers is intuitive,
+but here are a few tips that will keep you out of trouble in the corner cases:
+
+* Don't stick adjoining pre-release tags together without a dot or number
+  between them.  Version ``1.9adev`` is the ``adev`` prerelease of ``1.9``,
+  *not* a development pre-release of ``1.9a``.  Use ``.dev`` instead, as in
+  ``1.9a.dev``, or separate the prerelease tags with a number, as in
+  ``1.9a0dev``.  ``1.9a.dev``, ``1.9a0dev``, and even ``1.9.a.dev`` are
+  identical versions from setuptools' point of view, so you can use whatever
+  scheme you prefer.
+
+* If you want to be certain that your chosen numbering scheme works the way
+  you think it will, you can use the ``pkg_resources.parse_version()`` function
+  to compare different version numbers::
+
+    >>> from pkg_resources import parse_version
+    >>> parse_version('1.9.a.dev') == parse_version('1.9a0dev')
+    True
+    >>> parse_version('2.1-rc2') < parse_version('2.1')
+    True
+    >>> parse_version('0.6a9dev-r41475') < parse_version('0.6a9')
+    True
+
+Once you've decided on a version numbering scheme for your project, you can
+have setuptools automatically tag your in-development releases with various
+pre- or post-release tags.  See the following sections for more details:
+
+* `Tagging and "Daily Build" or "Snapshot" Releases`_
+* `Managing "Continuous Releases" Using Subversion`_
+* The `egg_info`_ command
+
+
+New and Changed ``setup()`` Keywords
+====================================
+
+The following keyword arguments to ``setup()`` are added or changed by
+``setuptools``.  All of them are optional; you do not have to supply them
+unless you need the associated ``setuptools`` feature.
+
+``include_package_data``
+    If set to ``True``, this tells ``setuptools`` to automatically include any
+    data files it finds inside your package directories that are specified by
+    your ``MANIFEST.in`` file.  For more information, see the section below on
+    `Including Data Files`_.
+
+``exclude_package_data``
+    A dictionary mapping package names to lists of glob patterns that should
+    be *excluded* from your package directories.  You can use this to trim back
+    any excess files included by ``include_package_data``.  For a complete
+    description and examples, see the section below on `Including Data Files`_.
+
+``package_data``
+    A dictionary mapping package names to lists of glob patterns.  For a
+    complete description and examples, see the section below on `Including
+    Data Files`_.  You do not need to use this option if you are using
+    ``include_package_data``, unless you need to add e.g. files that are
+    generated by your setup script and build process.  (And are therefore not
+    in source control or are files that you don't want to include in your
+    source distribution.)
+
+``zip_safe``
+    A boolean (True or False) flag specifying whether the project can be
+    safely installed and run from a zip file.  If this argument is not
+    supplied, the ``bdist_egg`` command will have to analyze all of your
+    project's contents for possible problems each time it builds an egg.
+
+``install_requires``
+    A string or list of strings specifying what other distributions need to
+    be installed when this one is.  See the section below on `Declaring
+    Dependencies`_ for details and examples of the format of this argument.
+
+``entry_points``
+    A dictionary mapping entry point group names to strings or lists of strings
+    defining the entry points.  Entry points are used to support dynamic
+    discovery of services or plugins provided by a project.  See `Dynamic
+    Discovery of Services and Plugins`_ for details and examples of the format
+    of this argument.  In addition, this keyword is used to support `Automatic
+    Script Creation`_.
+
+``extras_require``
+    A dictionary mapping names of "extras" (optional features of your project)
+    to strings or lists of strings specifying what other distributions must be
+    installed to support those features.  See the section below on `Declaring
+    Dependencies`_ for details and examples of the format of this argument.
+
+``python_requires``
+    A string corresponding to a version specifier (as defined in PEP 440) for
+    the Python version, used to specify the Requires-Python defined in PEP 345.
+
+``setup_requires``
+    A string or list of strings specifying what other distributions need to
+    be present in order for the *setup script* to run.  ``setuptools`` will
+    attempt to obtain these (even going so far as to download them using
+    ``EasyInstall``) before processing the rest of the setup script or commands.
+    This argument is needed if you are using distutils extensions as part of
+    your build process; for example, extensions that process setup() arguments
+    and turn them into EGG-INFO metadata files.
+
+    (Note: projects listed in ``setup_requires`` will NOT be automatically
+    installed on the system where the setup script is being run.  They are
+    simply downloaded to the ./.eggs directory if they're not locally available
+    already.  If you want them to be installed, as well as being available
+    when the setup script is run, you should add them to ``install_requires``
+    **and** ``setup_requires``.)
+
+``dependency_links``
+    A list of strings naming URLs to be searched when satisfying dependencies.
+    These links will be used if needed to install packages specified by
+    ``setup_requires`` or ``tests_require``.  They will also be written into
+    the egg's metadata for use by tools like EasyInstall to use when installing
+    an ``.egg`` file.
+
+``namespace_packages``
+    A list of strings naming the project's "namespace packages".  A namespace
+    package is a package that may be split across multiple project
+    distributions.  For example, Zope 3's ``zope`` package is a namespace
+    package, because subpackages like ``zope.interface`` and ``zope.publisher``
+    may be distributed separately.  The egg runtime system can automatically
+    merge such subpackages into a single parent package at runtime, as long
+    as you declare them in each project that contains any subpackages of the
+    namespace package, and as long as the namespace package's ``__init__.py``
+    does not contain any code other than a namespace declaration.  See the
+    section below on `Namespace Packages`_ for more information.
+
+``test_suite``
+    A string naming a ``unittest.TestCase`` subclass (or a package or module
+    containing one or more of them, or a method of such a subclass), or naming
+    a function that can be called with no arguments and returns a
+    ``unittest.TestSuite``.  If the named suite is a module, and the module
+    has an ``additional_tests()`` function, it is called and the results are
+    added to the tests to be run.  If the named suite is a package, any
+    submodules and subpackages are recursively added to the overall test suite.
+
+    Specifying this argument enables use of the `test`_ command to run the
+    specified test suite, e.g. via ``setup.py test``.  See the section on the
+    `test`_ command below for more details.
+
+``tests_require``
+    If your project's tests need one or more additional packages besides those
+    needed to install it, you can use this option to specify them.  It should
+    be a string or list of strings specifying what other distributions need to
+    be present for the package's tests to run.  When you run the ``test``
+    command, ``setuptools`` will  attempt to obtain these (even going
+    so far as to download them using ``EasyInstall``).  Note that these
+    required projects will *not* be installed on the system where the tests
+    are run, but only downloaded to the project's setup directory if they're
+    not already installed locally.
+
+.. _test_loader:
+
+``test_loader``
+    If you would like to use a different way of finding tests to run than what
+    setuptools normally uses, you can specify a module name and class name in
+    this argument.  The named class must be instantiable with no arguments, and
+    its instances must support the ``loadTestsFromNames()`` method as defined
+    in the Python ``unittest`` module's ``TestLoader`` class.  Setuptools will
+    pass only one test "name" in the `names` argument: the value supplied for
+    the ``test_suite`` argument.  The loader you specify may interpret this
+    string in any way it likes, as there are no restrictions on what may be
+    contained in a ``test_suite`` string.
+
+    The module name and class name must be separated by a ``:``.  The default
+    value of this argument is ``"setuptools.command.test:ScanningLoader"``.  If
+    you want to use the default ``unittest`` behavior, you can specify
+    ``"unittest:TestLoader"`` as your ``test_loader`` argument instead.  This
+    will prevent automatic scanning of submodules and subpackages.
+
+    The module and class you specify here may be contained in another package,
+    as long as you use the ``tests_require`` option to ensure that the package
+    containing the loader class is available when the ``test`` command is run.
+
+``eager_resources``
+    A list of strings naming resources that should be extracted together, if
+    any of them is needed, or if any C extensions included in the project are
+    imported.  This argument is only useful if the project will be installed as
+    a zipfile, and there is a need to have all of the listed resources be
+    extracted to the filesystem *as a unit*.  Resources listed here
+    should be '/'-separated paths, relative to the source root, so to list a
+    resource ``foo.png`` in package ``bar.baz``, you would include the string
+    ``bar/baz/foo.png`` in this argument.
+
+    If you only need to obtain resources one at a time, or you don't have any C
+    extensions that access other files in the project (such as data files or
+    shared libraries), you probably do NOT need this argument and shouldn't
+    mess with it.  For more details on how this argument works, see the section
+    below on `Automatic Resource Extraction`_.
+
+``use_2to3``
+    Convert the source code from Python 2 to Python 3 with 2to3 during the
+    build process. See :doc:`python3` for more details.
+
+``convert_2to3_doctests``
+    List of doctest source files that need to be converted with 2to3.
+    See :doc:`python3` for more details.
+
+``use_2to3_fixers``
+    A list of modules to search for additional fixers to be used during
+    the 2to3 conversion. See :doc:`python3` for more details.
+
+``project_urls``
+    An arbitrary map of URL names to hyperlinks, allowing more extensible
+    documentation of where various resources can be found than the simple
+    ``url`` and ``download_url`` options provide.
+
+
+Using ``find_packages()``
+-------------------------
+
+For simple projects, it's usually easy enough to manually add packages to
+the ``packages`` argument of ``setup()``.  However, for very large projects
+(Twisted, PEAK, Zope, Chandler, etc.), it can be a big burden to keep the
+package list updated.  That's what ``setuptools.find_packages()`` is for.
+
+``find_packages()`` takes a source directory and two lists of package name
+patterns to exclude and include.  If omitted, the source directory defaults to
+the same
+directory as the setup script.  Some projects use a ``src`` or ``lib``
+directory as the root of their source tree, and those projects would of course
+use ``"src"`` or ``"lib"`` as the first argument to ``find_packages()``.  (And
+such projects also need something like ``package_dir={'':'src'}`` in their
+``setup()`` arguments, but that's just a normal distutils thing.)
+
+Anyway, ``find_packages()`` walks the target directory, filtering by inclusion
+patterns, and finds Python packages (any directory). Packages are only
+recognized if they include an ``__init__.py`` file. Finally, exclusion 
+patterns are applied to remove matching packages.
+
+Inclusion and exclusion patterns are package names, optionally including
+wildcards.  For
+example, ``find_packages(exclude=["*.tests"])`` will exclude all packages whose
+last name part is ``tests``.   Or, ``find_packages(exclude=["*.tests",
+"*.tests.*"])`` will also exclude any subpackages of packages named ``tests``,
+but it still won't exclude a top-level ``tests`` package or the children
+thereof.  In fact, if you really want no ``tests`` packages at all, you'll need
+something like this::
+
+    find_packages(exclude=["*.tests", "*.tests.*", "tests.*", "tests"])
+
+in order to cover all the bases.  Really, the exclusion patterns are intended
+to cover simpler use cases than this, like excluding a single, specified
+package and its subpackages.
+
+Regardless of the parameters, the ``find_packages()``
+function returns a list of package names suitable for use as the ``packages``
+argument to ``setup()``, and so is usually the easiest way to set that
+argument in your setup script.  Especially since it frees you from having to
+remember to modify your setup script whenever your project grows additional
+top-level packages or subpackages.
+
+
+Automatic Script Creation
+=========================
+
+Packaging and installing scripts can be a bit awkward with the distutils.  For
+one thing, there's no easy way to have a script's filename match local
+conventions on both Windows and POSIX platforms.  For another, you often have
+to create a separate file just for the "main" script, when your actual "main"
+is a function in a module somewhere.  And even in Python 2.4, using the ``-m``
+option only works for actual ``.py`` files that aren't installed in a package.
+
+``setuptools`` fixes all of these problems by automatically generating scripts
+for you with the correct extension, and on Windows it will even create an
+``.exe`` file so that users don't have to change their ``PATHEXT`` settings.
+The way to use this feature is to define "entry points" in your setup script
+that indicate what function the generated script should import and run.  For
+example, to create two console scripts called ``foo`` and ``bar``, and a GUI
+script called ``baz``, you might do something like this::
+
+    setup(
+        # other arguments here...
+        entry_points={
+            'console_scripts': [
+                'foo = my_package.some_module:main_func',
+                'bar = other_module:some_func',
+            ],
+            'gui_scripts': [
+                'baz = my_package_gui:start_func',
+            ]
+        }
+    )
+
+When this project is installed on non-Windows platforms (using "setup.py
+install", "setup.py develop", or by using EasyInstall), a set of ``foo``,
+``bar``, and ``baz`` scripts will be installed that import ``main_func`` and
+``some_func`` from the specified modules.  The functions you specify are called
+with no arguments, and their return value is passed to ``sys.exit()``, so you
+can return an errorlevel or message to print to stderr.
+
+On Windows, a set of ``foo.exe``, ``bar.exe``, and ``baz.exe`` launchers are
+created, alongside a set of ``foo.py``, ``bar.py``, and ``baz.pyw`` files.  The
+``.exe`` wrappers find and execute the right version of Python to run the
+``.py`` or ``.pyw`` file.
+
+You may define as many "console script" and "gui script" entry points as you
+like, and each one can optionally specify "extras" that it depends on, that
+will be added to ``sys.path`` when the script is run.  For more information on
+"extras", see the section below on `Declaring Extras`_.  For more information
+on "entry points" in general, see the section below on `Dynamic Discovery of
+Services and Plugins`_.
+
+
+"Eggsecutable" Scripts
+----------------------
+
+Occasionally, there are situations where it's desirable to make an ``.egg``
+file directly executable.  You can do this by including an entry point such
+as the following::
+
+    setup(
+        # other arguments here...
+        entry_points={
+            'setuptools.installation': [
+                'eggsecutable = my_package.some_module:main_func',
+            ]
+        }
+    )
+
+Any eggs built from the above setup script will include a short executable
+prelude that imports and calls ``main_func()`` from ``my_package.some_module``.
+The prelude can be run on Unix-like platforms (including Mac and Linux) by
+invoking the egg with ``/bin/sh``, or by enabling execute permissions on the
+``.egg`` file.  For the executable prelude to run, the appropriate version of
+Python must be available via the ``PATH`` environment variable, under its
+"long" name.  That is, if the egg is built for Python 2.3, there must be a
+``python2.3`` executable present in a directory on ``PATH``.
+
+This feature is primarily intended to support ez_setup the installation of
+setuptools itself on non-Windows platforms, but may also be useful for other
+projects as well.
+
+IMPORTANT NOTE: Eggs with an "eggsecutable" header cannot be renamed, or
+invoked via symlinks.  They *must* be invoked using their original filename, in
+order to ensure that, once running, ``pkg_resources`` will know what project
+and version is in use.  The header script will check this and exit with an
+error if the ``.egg`` file has been renamed or is invoked via a symlink that
+changes its base name.
+
+
+Declaring Dependencies
+======================
+
+``setuptools`` supports automatically installing dependencies when a package is
+installed, and including information about dependencies in Python Eggs (so that
+package management tools like EasyInstall can use the information).
+
+``setuptools`` and ``pkg_resources`` use a common syntax for specifying a
+project's required dependencies.  This syntax consists of a project's PyPI
+name, optionally followed by a comma-separated list of "extras" in square
+brackets, optionally followed by a comma-separated list of version
+specifiers.  A version specifier is one of the operators ``<``, ``>``, ``<=``,
+``>=``, ``==`` or ``!=``, followed by a version identifier.  Tokens may be
+separated by whitespace, but any whitespace or nonstandard characters within a
+project name or version identifier must be replaced with ``-``.
+
+Version specifiers for a given project are internally sorted into ascending
+version order, and used to establish what ranges of versions are acceptable.
+Adjacent redundant conditions are also consolidated (e.g. ``">1, >2"`` becomes
+``">2"``, and ``"<2,<3"`` becomes ``"<2"``). ``"!="`` versions are excised from
+the ranges they fall within.  A project's version is then checked for
+membership in the resulting ranges. (Note that providing conflicting conditions
+for the same version (e.g. "<2,>=2" or "==2,!=2") is meaningless and may
+therefore produce bizarre results.)
+
+Here are some example requirement specifiers::
+
+    docutils >= 0.3
+
+    # comment lines and \ continuations are allowed in requirement strings
+    BazSpam ==1.1, ==1.2, ==1.3, ==1.4, ==1.5, \
+        ==1.6, ==1.7  # and so are line-end comments
+
+    PEAK[FastCGI, reST]>=0.5a4
+
+    setuptools==0.5a7
+
+The simplest way to include requirement specifiers is to use the
+``install_requires`` argument to ``setup()``.  It takes a string or list of
+strings containing requirement specifiers.  If you include more than one
+requirement in a string, each requirement must begin on a new line.
+
+This has three effects:
+
+1. When your project is installed, either by using EasyInstall, ``setup.py
+   install``, or ``setup.py develop``, all of the dependencies not already
+   installed will be located (via PyPI), downloaded, built (if necessary),
+   and installed.
+
+2. Any scripts in your project will be installed with wrappers that verify
+   the availability of the specified dependencies at runtime, and ensure that
+   the correct versions are added to ``sys.path`` (e.g. if multiple versions
+   have been installed).
+
+3. Python Egg distributions will include a metadata file listing the
+   dependencies.
+
+Note, by the way, that if you declare your dependencies in ``setup.py``, you do
+*not* need to use the ``require()`` function in your scripts or modules, as
+long as you either install the project or use ``setup.py develop`` to do
+development work on it.  (See `"Development Mode"`_ below for more details on
+using ``setup.py develop``.)
+
+
+Dependencies that aren't in PyPI
+--------------------------------
+
+If your project depends on packages that aren't registered in PyPI, you may
+still be able to depend on them, as long as they are available for download
+as:
+
+- an egg, in the standard distutils ``sdist`` format,
+- a single ``.py`` file, or
+- a VCS repository (Subversion, Mercurial, or Git).
+
+You just need to add some URLs to the ``dependency_links`` argument to
+``setup()``.
+
+The URLs must be either:
+
+1. direct download URLs,
+2. the URLs of web pages that contain direct download links, or
+3. the repository's URL
+
+In general, it's better to link to web pages, because it is usually less
+complex to update a web page than to release a new version of your project.
+You can also use a SourceForge ``showfiles.php`` link in the case where a
+package you depend on is distributed via SourceForge.
+
+If you depend on a package that's distributed as a single ``.py`` file, you
+must include an ``"#egg=project-version"`` suffix to the URL, to give a project
+name and version number.  (Be sure to escape any dashes in the name or version
+by replacing them with underscores.)  EasyInstall will recognize this suffix
+and automatically create a trivial ``setup.py`` to wrap the single ``.py`` file
+as an egg.
+
+In the case of a VCS checkout, you should also append ``#egg=project-version``
+in order to identify for what package that checkout should be used. You can
+append ``@REV`` to the URL's path (before the fragment) to specify a revision.
+Additionally, you can also force the VCS being used by prepending the URL with
+a certain prefix. Currently available are:
+
+-  ``svn+URL`` for Subversion,
+-  ``git+URL`` for Git, and
+-  ``hg+URL`` for Mercurial
+
+A more complete example would be:
+
+    ``vcs+proto://host/path@revision#egg=project-version``
+
+Be careful with the version. It should match the one inside the project files.
+If you want to disregard the version, you have to omit it both in the
+``requires`` and in the URL's fragment.
+
+This will do a checkout (or a clone, in Git and Mercurial parlance) to a
+temporary folder and run ``setup.py bdist_egg``.
+
+The ``dependency_links`` option takes the form of a list of URL strings.  For
+example, the below will cause EasyInstall to search the specified page for
+eggs or source distributions, if the package's dependencies aren't already
+installed::
+
+    setup(
+        ...
+        dependency_links=[
+            "http://peak.telecommunity.com/snapshots/"
+        ],
+    )
+
+
+.. _Declaring Extras:
+
+
+Declaring "Extras" (optional features with their own dependencies)
+------------------------------------------------------------------
+
+Sometimes a project has "recommended" dependencies, that are not required for
+all uses of the project.  For example, a project might offer optional PDF
+output if ReportLab is installed, and reStructuredText support if docutils is
+installed.  These optional features are called "extras", and setuptools allows
+you to define their requirements as well.  In this way, other projects that
+require these optional features can force the additional requirements to be
+installed, by naming the desired extras in their ``install_requires``.
+
+For example, let's say that Project A offers optional PDF and reST support::
+
+    setup(
+        name="Project-A",
+        ...
+        extras_require={
+            'PDF':  ["ReportLab>=1.2", "RXP"],
+            'reST': ["docutils>=0.3"],
+        }
+    )
+
+As you can see, the ``extras_require`` argument takes a dictionary mapping
+names of "extra" features, to strings or lists of strings describing those
+features' requirements.  These requirements will *not* be automatically
+installed unless another package depends on them (directly or indirectly) by
+including the desired "extras" in square brackets after the associated project
+name.  (Or if the extras were listed in a requirement spec on the EasyInstall
+command line.)
+
+Extras can be used by a project's `entry points`_ to specify dynamic
+dependencies.  For example, if Project A includes a "rst2pdf" script, it might
+declare it like this, so that the "PDF" requirements are only resolved if the
+"rst2pdf" script is run::
+
+    setup(
+        name="Project-A",
+        ...
+        entry_points={
+            'console_scripts': [
+                'rst2pdf = project_a.tools.pdfgen [PDF]',
+                'rst2html = project_a.tools.htmlgen',
+                # more script entry points ...
+            ],
+        }
+    )
+
+Projects can also use another project's extras when specifying dependencies.
+For example, if project B needs "project A" with PDF support installed, it
+might declare the dependency like this::
+
+    setup(
+        name="Project-B",
+        install_requires=["Project-A[PDF]"],
+        ...
+    )
+
+This will cause ReportLab to be installed along with project A, if project B is
+installed -- even if project A was already installed.  In this way, a project
+can encapsulate groups of optional "downstream dependencies" under a feature
+name, so that packages that depend on it don't have to know what the downstream
+dependencies are.  If a later version of Project A builds in PDF support and
+no longer needs ReportLab, or if it ends up needing other dependencies besides
+ReportLab in order to provide PDF support, Project B's setup information does
+not need to change, but the right packages will still be installed if needed.
+
+Note, by the way, that if a project ends up not needing any other packages to
+support a feature, it should keep an empty requirements list for that feature
+in its ``extras_require`` argument, so that packages depending on that feature
+don't break (due to an invalid feature name).  For example, if Project A above
+builds in PDF support and no longer needs ReportLab, it could change its
+setup to this::
+
+    setup(
+        name="Project-A",
+        ...
+        extras_require={
+            'PDF':  [],
+            'reST': ["docutils>=0.3"],
+        }
+    )
+
+so that Package B doesn't have to remove the ``[PDF]`` from its requirement
+specifier.
+
+
+.. _Platform Specific Dependencies:
+
+
+Declaring platform specific dependencies
+----------------------------------------
+
+Sometimes a project might require a dependency to run on a specific platform.
+This could to a package that back ports a module so that it can be used in
+older python versions.  Or it could be a package that is required to run on a
+specific operating system.  This will allow a project to work on multiple
+different platforms without installing dependencies that are not required for
+a platform that is installing the project.
+
+For example, here is a project that uses the ``enum`` module and ``pywin32``::
+
+    setup(
+        name="Project",
+        ...
+        install_requires=[
+            'enum34;python_version<"3.4"',
+            'pywin32 >= 1.0;platform_system=="Windows"'
+        ]
+    )
+
+Since the ``enum`` module was added in Python 3.4, it should only be installed
+if the python version is earlier.  Since ``pywin32`` will only be used on
+windows, it should only be installed when the operating system is Windows.
+Specifying version requirements for the dependencies is supported as normal.
+
+The environmental markers that may be used for testing platform types are
+detailed in `PEP 508`_.
+
+.. _PEP 508: https://www.python.org/dev/peps/pep-0508/
+
+Including Data Files
+====================
+
+The distutils have traditionally allowed installation of "data files", which
+are placed in a platform-specific location.  However, the most common use case
+for data files distributed with a package is for use *by* the package, usually
+by including the data files in the package directory.
+
+Setuptools offers three ways to specify data files to be included in your
+packages.  First, you can simply use the ``include_package_data`` keyword,
+e.g.::
+
+    from setuptools import setup, find_packages
+    setup(
+        ...
+        include_package_data=True
+    )
+
+This tells setuptools to install any data files it finds in your packages.
+The data files must be specified via the distutils' ``MANIFEST.in`` file.
+(They can also be tracked by a revision control system, using an appropriate
+plugin.  See the section below on `Adding Support for Revision Control
+Systems`_ for information on how to write such plugins.)
+
+If you want finer-grained control over what files are included (for example,
+if you have documentation files in your package directories and want to exclude
+them from installation), then you can also use the ``package_data`` keyword,
+e.g.::
+
+    from setuptools import setup, find_packages
+    setup(
+        ...
+        package_data={
+            # If any package contains *.txt or *.rst files, include them:
+            '': ['*.txt', '*.rst'],
+            # And include any *.msg files found in the 'hello' package, too:
+            'hello': ['*.msg'],
+        }
+    )
+
+The ``package_data`` argument is a dictionary that maps from package names to
+lists of glob patterns.  The globs may include subdirectory names, if the data
+files are contained in a subdirectory of the package.  For example, if the
+package tree looks like this::
+
+    setup.py
+    src/
+        mypkg/
+            __init__.py
+            mypkg.txt
+            data/
+                somefile.dat
+                otherdata.dat
+
+The setuptools setup file might look like this::
+
+    from setuptools import setup, find_packages
+    setup(
+        ...
+        packages=find_packages('src'),  # include all packages under src
+        package_dir={'':'src'},   # tell distutils packages are under src
+
+        package_data={
+            # If any package contains *.txt files, include them:
+            '': ['*.txt'],
+            # And include any *.dat files found in the 'data' subdirectory
+            # of the 'mypkg' package, also:
+            'mypkg': ['data/*.dat'],
+        }
+    )
+
+Notice that if you list patterns in ``package_data`` under the empty string,
+these patterns are used to find files in every package, even ones that also
+have their own patterns listed.  Thus, in the above example, the ``mypkg.txt``
+file gets included even though it's not listed in the patterns for ``mypkg``.
+
+Also notice that if you use paths, you *must* use a forward slash (``/``) as
+the path separator, even if you are on Windows.  Setuptools automatically
+converts slashes to appropriate platform-specific separators at build time.
+
+If datafiles are contained in a subdirectory of a package that isn't a package
+itself (no ``__init__.py``), then the subdirectory names (or ``*``) are required
+in the ``package_data`` argument (as shown above with ``'data/*.dat'``).
+
+When building an ``sdist``, the datafiles are also drawn from the
+``package_name.egg-info/SOURCES.txt`` file, so make sure that this is removed if
+the ``setup.py`` ``package_data`` list is updated before calling ``setup.py``.
+
+(Note: although the ``package_data`` argument was previously only available in
+``setuptools``, it was also added to the Python ``distutils`` package as of
+Python 2.4; there is `some documentation for the feature`__ available on the
+python.org website.  If using the setuptools-specific ``include_package_data``
+argument, files specified by ``package_data`` will *not* be automatically
+added to the manifest unless they are listed in the MANIFEST.in file.)
+
+__ http://docs.python.org/dist/node11.html
+
+Sometimes, the ``include_package_data`` or ``package_data`` options alone
+aren't sufficient to precisely define what files you want included.  For
+example, you may want to include package README files in your revision control
+system and source distributions, but exclude them from being installed.  So,
+setuptools offers an ``exclude_package_data`` option as well, that allows you
+to do things like this::
+
+    from setuptools import setup, find_packages
+    setup(
+        ...
+        packages=find_packages('src'),  # include all packages under src
+        package_dir={'':'src'},   # tell distutils packages are under src
+
+        include_package_data=True,    # include everything in source control
+
+        # ...but exclude README.txt from all packages
+        exclude_package_data={'': ['README.txt']},
+    )
+
+The ``exclude_package_data`` option is a dictionary mapping package names to
+lists of wildcard patterns, just like the ``package_data`` option.  And, just
+as with that option, a key of ``''`` will apply the given pattern(s) to all
+packages.  However, any files that match these patterns will be *excluded*
+from installation, even if they were listed in ``package_data`` or were
+included as a result of using ``include_package_data``.
+
+In summary, the three options allow you to:
+
+``include_package_data``
+    Accept all data files and directories matched by ``MANIFEST.in``.
+
+``package_data``
+    Specify additional patterns to match files that may or may
+    not be matched by ``MANIFEST.in`` or found in source control.
+
+``exclude_package_data``
+    Specify patterns for data files and directories that should *not* be
+    included when a package is installed, even if they would otherwise have
+    been included due to the use of the preceding options.
+
+NOTE: Due to the way the distutils build process works, a data file that you
+include in your project and then stop including may be "orphaned" in your
+project's build directories, requiring you to run ``setup.py clean --all`` to
+fully remove them.  This may also be important for your users and contributors
+if they track intermediate revisions of your project using Subversion; be sure
+to let them know when you make changes that remove files from inclusion so they
+can run ``setup.py clean --all``.
+
+
+Accessing Data Files at Runtime
+-------------------------------
+
+Typically, existing programs manipulate a package's ``__file__`` attribute in
+order to find the location of data files.  However, this manipulation isn't
+compatible with PEP 302-based import hooks, including importing from zip files
+and Python Eggs.  It is strongly recommended that, if you are using data files,
+you should use the :ref:`ResourceManager API` of ``pkg_resources`` to access
+them.  The ``pkg_resources`` module is distributed as part of setuptools, so if
+you're using setuptools to distribute your package, there is no reason not to
+use its resource management API.  See also `Accessing Package Resources`_ for
+a quick example of converting code that uses ``__file__`` to use
+``pkg_resources`` instead.
+
+.. _Accessing Package Resources: http://peak.telecommunity.com/DevCenter/PythonEggs#accessing-package-resources
+
+
+Non-Package Data Files
+----------------------
+
+The ``distutils`` normally install general "data files" to a platform-specific
+location (e.g. ``/usr/share``).  This feature intended to be used for things
+like documentation, example configuration files, and the like.  ``setuptools``
+does not install these data files in a separate location, however.  They are
+bundled inside the egg file or directory, alongside the Python modules and
+packages.  The data files can also be accessed using the :ref:`ResourceManager
+API`, by specifying a ``Requirement`` instead of a package name::
+
+    from pkg_resources import Requirement, resource_filename
+    filename = resource_filename(Requirement.parse("MyProject"),"sample.conf")
+
+The above code will obtain the filename of the "sample.conf" file in the data
+root of the "MyProject" distribution.
+
+Note, by the way, that this encapsulation of data files means that you can't
+actually install data files to some arbitrary location on a user's machine;
+this is a feature, not a bug.  You can always include a script in your
+distribution that extracts and copies your the documentation or data files to
+a user-specified location, at their discretion.  If you put related data files
+in a single directory, you can use ``resource_filename()`` with the directory
+name to get a filesystem directory that then can be copied with the ``shutil``
+module.  (Even if your package is installed as a zipfile, calling
+``resource_filename()`` on a directory will return an actual filesystem
+directory, whose contents will be that entire subtree of your distribution.)
+
+(Of course, if you're writing a new package, you can just as easily place your
+data files or directories inside one of your packages, rather than using the
+distutils' approach.  However, if you're updating an existing application, it
+may be simpler not to change the way it currently specifies these data files.)
+
+
+Automatic Resource Extraction
+-----------------------------
+
+If you are using tools that expect your resources to be "real" files, or your
+project includes non-extension native libraries or other files that your C
+extensions expect to be able to access, you may need to list those files in
+the ``eager_resources`` argument to ``setup()``, so that the files will be
+extracted together, whenever a C extension in the project is imported.
+
+This is especially important if your project includes shared libraries *other*
+than distutils-built C extensions, and those shared libraries use file
+extensions other than ``.dll``, ``.so``, or ``.dylib``, which are the
+extensions that setuptools 0.6a8 and higher automatically detects as shared
+libraries and adds to the ``native_libs.txt`` file for you.  Any shared
+libraries whose names do not end with one of those extensions should be listed
+as ``eager_resources``, because they need to be present in the filesystem when
+he C extensions that link to them are used.
+
+The ``pkg_resources`` runtime for compressed packages will automatically
+extract *all* C extensions and ``eager_resources`` at the same time, whenever
+*any* C extension or eager resource is requested via the ``resource_filename()``
+API.  (C extensions are imported using ``resource_filename()`` internally.)
+This ensures that C extensions will see all of the "real" files that they
+expect to see.
+
+Note also that you can list directory resource names in ``eager_resources`` as
+well, in which case the directory's contents (including subdirectories) will be
+extracted whenever any C extension or eager resource is requested.
+
+Please note that if you're not sure whether you need to use this argument, you
+don't!  It's really intended to support projects with lots of non-Python
+dependencies and as a last resort for crufty projects that can't otherwise
+handle being compressed.  If your package is pure Python, Python plus data
+files, or Python plus C, you really don't need this.  You've got to be using
+either C or an external program that needs "real" files in your project before
+there's any possibility of ``eager_resources`` being relevant to your project.
+
+
+Extensible Applications and Frameworks
+======================================
+
+
+.. _Entry Points:
+
+Dynamic Discovery of Services and Plugins
+-----------------------------------------
+
+``setuptools`` supports creating libraries that "plug in" to extensible
+applications and frameworks, by letting you register "entry points" in your
+project that can be imported by the application or framework.
+
+For example, suppose that a blogging tool wants to support plugins
+that provide translation for various file types to the blog's output format.
+The framework might define an "entry point group" called ``blogtool.parsers``,
+and then allow plugins to register entry points for the file extensions they
+support.
+
+This would allow people to create distributions that contain one or more
+parsers for different file types, and then the blogging tool would be able to
+find the parsers at runtime by looking up an entry point for the file
+extension (or mime type, or however it wants to).
+
+Note that if the blogging tool includes parsers for certain file formats, it
+can register these as entry points in its own setup script, which means it
+doesn't have to special-case its built-in formats.  They can just be treated
+the same as any other plugin's entry points would be.
+
+If you're creating a project that plugs in to an existing application or
+framework, you'll need to know what entry points or entry point groups are
+defined by that application or framework.  Then, you can register entry points
+in your setup script.  Here are a few examples of ways you might register an
+``.rst`` file parser entry point in the ``blogtool.parsers`` entry point group,
+for our hypothetical blogging tool::
+
+    setup(
+        # ...
+        entry_points={'blogtool.parsers': '.rst = some_module:SomeClass'}
+    )
+
+    setup(
+        # ...
+        entry_points={'blogtool.parsers': ['.rst = some_module:a_func']}
+    )
+
+    setup(
+        # ...
+        entry_points="""
+            [blogtool.parsers]
+            .rst = some.nested.module:SomeClass.some_classmethod [reST]
+        """,
+        extras_require=dict(reST="Docutils>=0.3.5")
+    )
+
+The ``entry_points`` argument to ``setup()`` accepts either a string with
+``.ini``-style sections, or a dictionary mapping entry point group names to
+either strings or lists of strings containing entry point specifiers.  An
+entry point specifier consists of a name and value, separated by an ``=``
+sign.  The value consists of a dotted module name, optionally followed by a
+``:`` and a dotted identifier naming an object within the module.  It can
+also include a bracketed list of "extras" that are required for the entry
+point to be used.  When the invoking application or framework requests loading
+of an entry point, any requirements implied by the associated extras will be
+passed to ``pkg_resources.require()``, so that an appropriate error message
+can be displayed if the needed package(s) are missing.  (Of course, the
+invoking app or framework can ignore such errors if it wants to make an entry
+point optional if a requirement isn't installed.)
+
+
+Defining Additional Metadata
+----------------------------
+
+Some extensible applications and frameworks may need to define their own kinds
+of metadata to include in eggs, which they can then access using the
+``pkg_resources`` metadata APIs.  Ordinarily, this is done by having plugin
+developers include additional files in their ``ProjectName.egg-info``
+directory.  However, since it can be tedious to create such files by hand, you
+may want to create a distutils extension that will create the necessary files
+from arguments to ``setup()``, in much the same way that ``setuptools`` does
+for many of the ``setup()`` arguments it adds.  See the section below on
+`Creating distutils Extensions`_ for more details, especially the subsection on
+`Adding new EGG-INFO Files`_.
+
+
+"Development Mode"
+==================
+
+Under normal circumstances, the ``distutils`` assume that you are going to
+build a distribution of your project, not use it in its "raw" or "unbuilt"
+form.  If you were to use the ``distutils`` that way, you would have to rebuild
+and reinstall your project every time you made a change to it during
+development.
+
+Another problem that sometimes comes up with the ``distutils`` is that you may
+need to do development on two related projects at the same time.  You may need
+to put both projects' packages in the same directory to run them, but need to
+keep them separate for revision control purposes.  How can you do this?
+
+Setuptools allows you to deploy your projects for use in a common directory or
+staging area, but without copying any files.  Thus, you can edit each project's
+code in its checkout directory, and only need to run build commands when you
+change a project's C extensions or similarly compiled files.  You can even
+deploy a project into another project's checkout directory, if that's your
+preferred way of working (as opposed to using a common independent staging area
+or the site-packages directory).
+
+To do this, use the ``setup.py develop`` command.  It works very similarly to
+``setup.py install`` or the EasyInstall tool, except that it doesn't actually
+install anything.  Instead, it creates a special ``.egg-link`` file in the
+deployment directory, that links to your project's source code.  And, if your
+deployment directory is Python's ``site-packages`` directory, it will also
+update the ``easy-install.pth`` file to include your project's source code,
+thereby making it available on ``sys.path`` for all programs using that Python
+installation.
+
+If you have enabled the ``use_2to3`` flag, then of course the ``.egg-link``
+will not link directly to your source code when run under Python 3, since
+that source code would be made for Python 2 and not work under Python 3.
+Instead the ``setup.py develop`` will build Python 3 code under the ``build``
+directory, and link there. This means that after doing code changes you will
+have to run ``setup.py build`` before these changes are picked up by your
+Python 3 installation.
+
+In addition, the ``develop`` command creates wrapper scripts in the target
+script directory that will run your in-development scripts after ensuring that
+all your ``install_requires`` packages are available on ``sys.path``.
+
+You can deploy the same project to multiple staging areas, e.g. if you have
+multiple projects on the same machine that are sharing the same project you're
+doing development work.
+
+When you're done with a given development task, you can remove the project
+source from a staging area using ``setup.py develop --uninstall``, specifying
+the desired staging area if it's not the default.
+
+There are several options to control the precise behavior of the ``develop``
+command; see the section on the `develop`_ command below for more details.
+
+Note that you can also apply setuptools commands to non-setuptools projects,
+using commands like this::
+
+   python -c "import setuptools; execfile('setup.py')" develop
+
+That is, you can simply list the normal setup commands and options following
+the quoted part.
+
+
+Distributing a ``setuptools``-based project
+===========================================
+
+Using ``setuptools``...  Without bundling it!
+---------------------------------------------
+
+.. warning:: **ez_setup** is deprecated in favor of PIP with **PEP-518** support.
+
+Your users might not have ``setuptools`` installed on their machines, or even
+if they do, it might not be the right version.  Fixing this is easy; just
+download `ez_setup.py`_, and put it in the same directory as your ``setup.py``
+script.  (Be sure to add it to your revision control system, too.)  Then add
+these two lines to the very top of your setup script, before the script imports
+anything from setuptools:
+
+.. code-block:: python
+
+    import ez_setup
+    ez_setup.use_setuptools()
+
+That's it.  The ``ez_setup`` module will automatically download a matching
+version of ``setuptools`` from PyPI, if it isn't present on the target system.
+Whenever you install an updated version of setuptools, you should also update
+your projects' ``ez_setup.py`` files, so that a matching version gets installed
+on the target machine(s).
+
+By the way, setuptools supports the new PyPI "upload" command, so you can use
+``setup.py sdist upload`` or ``setup.py bdist_egg upload`` to upload your
+source or egg distributions respectively.  Your project's current version must
+be registered with PyPI first, of course; you can use ``setup.py register`` to
+do that.  Or you can do it all in one step, e.g. ``setup.py register sdist
+bdist_egg upload`` will register the package, build source and egg
+distributions, and then upload them both to PyPI, where they'll be easily
+found by other projects that depend on them.
+
+(By the way, if you need to distribute a specific version of ``setuptools``,
+you can specify the exact version and base download URL as parameters to the
+``use_setuptools()`` function.  See the function's docstring for details.)
+
+
+What Your Users Should Know
+---------------------------
+
+In general, a setuptools-based project looks just like any distutils-based
+project -- as long as your users have an internet connection and are installing
+to ``site-packages``, that is.  But for some users, these conditions don't
+apply, and they may become frustrated if this is their first encounter with
+a setuptools-based project.  To keep these users happy, you should review the
+following topics in your project's installation instructions, if they are
+relevant to your project and your target audience isn't already familiar with
+setuptools and ``easy_install``.
+
+Network Access
+    If your project is using ``ez_setup``, you should inform users of the
+    need to either have network access, or to preinstall the correct version of
+    setuptools using the `EasyInstall installation instructions`_.  Those
+    instructions also have tips for dealing with firewalls as well as how to
+    manually download and install setuptools.
+
+Custom Installation Locations
+    You should inform your users that if they are installing your project to
+    somewhere other than the main ``site-packages`` directory, they should
+    first install setuptools using the instructions for `Custom Installation
+    Locations`_, before installing your project.
+
+Your Project's Dependencies
+    If your project depends on other projects that may need to be downloaded
+    from PyPI or elsewhere, you should list them in your installation
+    instructions, or tell users how to find out what they are.  While most
+    users will not need this information, any users who don't have unrestricted
+    internet access may have to find, download, and install the other projects
+    manually.  (Note, however, that they must still install those projects
+    using ``easy_install``, or your project will not know they are installed,
+    and your setup script will try to download them again.)
+
+    If you want to be especially friendly to users with limited network access,
+    you may wish to build eggs for your project and its dependencies, making
+    them all available for download from your site, or at least create a page
+    with links to all of the needed eggs.  In this way, users with limited
+    network access can manually download all the eggs to a single directory,
+    then use the ``-f`` option of ``easy_install`` to specify the directory
+    to find eggs in.  Users who have full network access can just use ``-f``
+    with the URL of your download page, and ``easy_install`` will find all the
+    needed eggs using your links directly.  This is also useful when your
+    target audience isn't able to compile packages (e.g. most Windows users)
+    and your package or some of its dependencies include C code.
+
+Revision Control System Users and Co-Developers
+    Users and co-developers who are tracking your in-development code using
+    a revision control system should probably read this manual's sections
+    regarding such development.  Alternately, you may wish to create a
+    quick-reference guide containing the tips from this manual that apply to
+    your particular situation.  For example, if you recommend that people use
+    ``setup.py develop`` when tracking your in-development code, you should let
+    them know that this needs to be run after every update or commit.
+
+    Similarly, if you remove modules or data files from your project, you
+    should remind them to run ``setup.py clean --all`` and delete any obsolete
+    ``.pyc`` or ``.pyo``.  (This tip applies to the distutils in general, not
+    just setuptools, but not everybody knows about them; be kind to your users
+    by spelling out your project's best practices rather than leaving them
+    guessing.)
+
+Creating System Packages
+    Some users want to manage all Python packages using a single package
+    manager, and sometimes that package manager isn't ``easy_install``!
+    Setuptools currently supports ``bdist_rpm``, ``bdist_wininst``, and
+    ``bdist_dumb`` formats for system packaging.  If a user has a locally-
+    installed "bdist" packaging tool that internally uses the distutils
+    ``install`` command, it should be able to work with ``setuptools``.  Some
+    examples of "bdist" formats that this should work with include the
+    ``bdist_nsi`` and ``bdist_msi`` formats for Windows.
+
+    However, packaging tools that build binary distributions by running
+    ``setup.py install`` on the command line or as a subprocess will require
+    modification to work with setuptools.  They should use the
+    ``--single-version-externally-managed`` option to the ``install`` command,
+    combined with the standard ``--root`` or ``--record`` options.
+    See the `install command`_ documentation below for more details.  The
+    ``bdist_deb`` command is an example of a command that currently requires
+    this kind of patching to work with setuptools.
+
+    If you or your users have a problem building a usable system package for
+    your project, please report the problem via the mailing list so that
+    either the "bdist" tool in question or setuptools can be modified to
+    resolve the issue.
+
+
+Setting the ``zip_safe`` flag
+-----------------------------
+
+For some use cases (such as bundling as part of a larger application), Python
+packages may be run directly from a zip file.
+Not all packages, however, are capable of running in compressed form, because
+they may expect to be able to access either source code or data files as
+normal operating system files.  So, ``setuptools`` can install your project
+as a zipfile or a directory, and its default choice is determined by the
+project's ``zip_safe`` flag.
+
+You can pass a True or False value for the ``zip_safe`` argument to the
+``setup()`` function, or you can omit it.  If you omit it, the ``bdist_egg``
+command will analyze your project's contents to see if it can detect any
+conditions that would prevent it from working in a zipfile.  It will output
+notices to the console about any such conditions that it finds.
+
+Currently, this analysis is extremely conservative: it will consider the
+project unsafe if it contains any C extensions or datafiles whatsoever.  This
+does *not* mean that the project can't or won't work as a zipfile!  It just
+means that the ``bdist_egg`` authors aren't yet comfortable asserting that
+the project *will* work.  If the project contains no C or data files, and does
+no ``__file__`` or ``__path__`` introspection or source code manipulation, then
+there is an extremely solid chance the project will work when installed as a
+zipfile.  (And if the project uses ``pkg_resources`` for all its data file
+access, then C extensions and other data files shouldn't be a problem at all.
+See the `Accessing Data Files at Runtime`_ section above for more information.)
+
+However, if ``bdist_egg`` can't be *sure* that your package will work, but
+you've checked over all the warnings it issued, and you are either satisfied it
+*will* work (or if you want to try it for yourself), then you should set
+``zip_safe`` to ``True`` in your ``setup()`` call.  If it turns out that it
+doesn't work, you can always change it to ``False``, which will force
+``setuptools`` to install your project as a directory rather than as a zipfile.
+
+Of course, the end-user can still override either decision, if they are using
+EasyInstall to install your package.  And, if you want to override for testing
+purposes, you can just run ``setup.py easy_install --zip-ok .`` or ``setup.py
+easy_install --always-unzip .`` in your project directory. to install the
+package as a zipfile or directory, respectively.
+
+In the future, as we gain more experience with different packages and become
+more satisfied with the robustness of the ``pkg_resources`` runtime, the
+"zip safety" analysis may become less conservative.  However, we strongly
+recommend that you determine for yourself whether your project functions
+correctly when installed as a zipfile, correct any problems if you can, and
+then make an explicit declaration of ``True`` or ``False`` for the ``zip_safe``
+flag, so that it will not be necessary for ``bdist_egg`` or ``EasyInstall`` to
+try to guess whether your project can work as a zipfile.
+
+
+Namespace Packages
+------------------
+
+Sometimes, a large package is more useful if distributed as a collection of
+smaller eggs.  However, Python does not normally allow the contents of a
+package to be retrieved from more than one location.  "Namespace packages"
+are a solution for this problem.  When you declare a package to be a namespace
+package, it means that the package has no meaningful contents in its
+``__init__.py``, and that it is merely a container for modules and subpackages.
+
+The ``pkg_resources`` runtime will then automatically ensure that the contents
+of namespace packages that are spread over multiple eggs or directories are
+combined into a single "virtual" package.
+
+The ``namespace_packages`` argument to ``setup()`` lets you declare your
+project's namespace packages, so that they will be included in your project's
+metadata.  The argument should list the namespace packages that the egg
+participates in.  For example, the ZopeInterface project might do this::
+
+    setup(
+        # ...
+        namespace_packages=['zope']
+    )
+
+because it contains a ``zope.interface`` package that lives in the ``zope``
+namespace package.  Similarly, a project for a standalone ``zope.publisher``
+would also declare the ``zope`` namespace package.  When these projects are
+installed and used, Python will see them both as part of a "virtual" ``zope``
+package, even though they will be installed in different locations.
+
+Namespace packages don't have to be top-level packages.  For example, Zope 3's
+``zope.app`` package is a namespace package, and in the future PEAK's
+``peak.util`` package will be too.
+
+Note, by the way, that your project's source tree must include the namespace
+packages' ``__init__.py`` files (and the ``__init__.py`` of any parent
+packages), in a normal Python package layout.  These ``__init__.py`` files
+*must* contain the line::
+
+    __import__('pkg_resources').declare_namespace(__name__)
+
+This code ensures that the namespace package machinery is operating and that
+the current package is registered as a namespace package.
+
+You must NOT include any other code and data in a namespace package's
+``__init__.py``.  Even though it may appear to work during development, or when
+projects are installed as ``.egg`` files, it will not work when the projects
+are installed using "system" packaging tools -- in such cases the
+``__init__.py`` files will not be installed, let alone executed.
+
+You must include the ``declare_namespace()``  line in the ``__init__.py`` of
+*every* project that has contents for the namespace package in question, in
+order to ensure that the namespace will be declared regardless of which
+project's copy of ``__init__.py`` is loaded first.  If the first loaded
+``__init__.py`` doesn't declare it, it will never *be* declared, because no
+other copies will ever be loaded!
+
+
+TRANSITIONAL NOTE
+~~~~~~~~~~~~~~~~~
+
+Setuptools automatically calls ``declare_namespace()`` for you at runtime,
+but future versions may *not*.  This is because the automatic declaration
+feature has some negative side effects, such as needing to import all namespace
+packages during the initialization of the ``pkg_resources`` runtime, and also
+the need for ``pkg_resources`` to be explicitly imported before any namespace
+packages work at all.  In some future releases, you'll be responsible
+for including your own declaration lines, and the automatic declaration feature
+will be dropped to get rid of the negative side effects.
+
+During the remainder of the current development cycle, therefore, setuptools
+will warn you about missing ``declare_namespace()`` calls in your
+``__init__.py`` files, and you should correct these as soon as possible
+before the compatibility support is removed.
+Namespace packages without declaration lines will not work
+correctly once a user has upgraded to a later version, so it's important that
+you make this change now in order to avoid having your code break in the field.
+Our apologies for the inconvenience, and thank you for your patience.
+
+
+
+Tagging and "Daily Build" or "Snapshot" Releases
+------------------------------------------------
+
+When a set of related projects are under development, it may be important to
+track finer-grained version increments than you would normally use for e.g.
+"stable" releases.  While stable releases might be measured in dotted numbers
+with alpha/beta/etc. status codes, development versions of a project often
+need to be tracked by revision or build number or even build date.  This is
+especially true when projects in development need to refer to one another, and
+therefore may literally need an up-to-the-minute version of something!
+
+To support these scenarios, ``setuptools`` allows you to "tag" your source and
+egg distributions by adding one or more of the following to the project's
+"official" version identifier:
+
+* A manually-specified pre-release tag, such as "build" or "dev", or a
+  manually-specified post-release tag, such as a build or revision number
+  (``--tag-build=STRING, -bSTRING``)
+
+* An 8-character representation of the build date (``--tag-date, -d``), as
+  a postrelease tag
+
+You can add these tags by adding ``egg_info`` and the desired options to
+the command line ahead of the ``sdist`` or ``bdist`` commands that you want
+to generate a daily build or snapshot for.  See the section below on the
+`egg_info`_ command for more details.
+
+(Also, before you release your project, be sure to see the section above on
+`Specifying Your Project's Version`_ for more information about how pre- and
+post-release tags affect how setuptools and EasyInstall interpret version
+numbers.  This is important in order to make sure that dependency processing
+tools will know which versions of your project are newer than others.)
+
+Finally, if you are creating builds frequently, and either building them in a
+downloadable location or are copying them to a distribution server, you should
+probably also check out the `rotate`_ command, which lets you automatically
+delete all but the N most-recently-modified distributions matching a glob
+pattern.  So, you can use a command line like::
+
+    setup.py egg_info -rbDEV bdist_egg rotate -m.egg -k3
+
+to build an egg whose version info includes 'DEV-rNNNN' (where NNNN is the
+most recent Subversion revision that affected the source tree), and then
+delete any egg files from the distribution directory except for the three
+that were built most recently.
+
+If you have to manage automated builds for multiple packages, each with
+different tagging and rotation policies, you may also want to check out the
+`alias`_ command, which would let each package define an alias like ``daily``
+that would perform the necessary tag, build, and rotate commands.  Then, a
+simpler script or cron job could just run ``setup.py daily`` in each project
+directory.  (And, you could also define sitewide or per-user default versions
+of the ``daily`` alias, so that projects that didn't define their own would
+use the appropriate defaults.)
+
+
+Generating Source Distributions
+-------------------------------
+
+``setuptools`` enhances the distutils' default algorithm for source file
+selection with pluggable endpoints for looking up files to include. If you are
+using a revision control system, and your source distributions only need to
+include files that you're tracking in revision control, use a corresponding
+plugin instead of writing a ``MANIFEST.in`` file. See the section below on
+`Adding Support for Revision Control Systems`_ for information on plugins.
+
+If you need to include automatically generated files, or files that are kept in
+an unsupported revision control system, you'll need to create a ``MANIFEST.in``
+file to specify any files that the default file location algorithm doesn't
+catch.  See the distutils documentation for more information on the format of
+the ``MANIFEST.in`` file.
+
+But, be sure to ignore any part of the distutils documentation that deals with
+``MANIFEST`` or how it's generated from ``MANIFEST.in``; setuptools shields you
+from these issues and doesn't work the same way in any case.  Unlike the
+distutils, setuptools regenerates the source distribution manifest file
+every time you build a source distribution, and it builds it inside the
+project's ``.egg-info`` directory, out of the way of your main project
+directory.  You therefore need not worry about whether it is up-to-date or not.
+
+Indeed, because setuptools' approach to determining the contents of a source
+distribution is so much simpler, its ``sdist`` command omits nearly all of
+the options that the distutils' more complex ``sdist`` process requires.  For
+all practical purposes, you'll probably use only the ``--formats`` option, if
+you use any option at all.
+
+
+Making your package available for EasyInstall
+---------------------------------------------
+
+If you use the ``register`` command (``setup.py register``) to register your
+package with PyPI, that's most of the battle right there.  (See the
+`docs for the register command`_ for more details.)
+
+.. _docs for the register command: http://docs.python.org/dist/package-index.html
+
+If you also use the `upload`_ command to upload actual distributions of your
+package, that's even better, because EasyInstall will be able to find and
+download them directly from your project's PyPI page.
+
+However, there may be reasons why you don't want to upload distributions to
+PyPI, and just want your existing distributions (or perhaps a Subversion
+checkout) to be used instead.
+
+So here's what you need to do before running the ``register`` command.  There
+are three ``setup()`` arguments that affect EasyInstall:
+
+``url`` and ``download_url``
+   These become links on your project's PyPI page.  EasyInstall will examine
+   them to see if they link to a package ("primary links"), or whether they are
+   HTML pages.  If they're HTML pages, EasyInstall scans all HREF's on the
+   page for primary links
+
+``long_description``
+   EasyInstall will check any URLs contained in this argument to see if they
+   are primary links.
+
+A URL is considered a "primary link" if it is a link to a .tar.gz, .tgz, .zip,
+.egg, .egg.zip, .tar.bz2, or .exe file, or if it has an ``#egg=project`` or
+``#egg=project-version`` fragment identifier attached to it.  EasyInstall
+attempts to determine a project name and optional version number from the text
+of a primary link *without* downloading it.  When it has found all the primary
+links, EasyInstall will select the best match based on requested version,
+platform compatibility, and other criteria.
+
+So, if your ``url`` or ``download_url`` point either directly to a downloadable
+source distribution, or to HTML page(s) that have direct links to such, then
+EasyInstall will be able to locate downloads automatically.  If you want to
+make Subversion checkouts available, then you should create links with either
+``#egg=project`` or ``#egg=project-version`` added to the URL.  You should
+replace ``project`` and ``version`` with the values they would have in an egg
+filename.  (Be sure to actually generate an egg and then use the initial part
+of the filename, rather than trying to guess what the escaped form of the
+project name and version number will be.)
+
+Note that Subversion checkout links are of lower precedence than other kinds
+of distributions, so EasyInstall will not select a Subversion checkout for
+downloading unless it has a version included in the ``#egg=`` suffix, and
+it's a higher version than EasyInstall has seen in any other links for your
+project.
+
+As a result, it's a common practice to use mark checkout URLs with a version of
+"dev" (i.e., ``#egg=projectname-dev``), so that users can do something like
+this::
+
+    easy_install --editable projectname==dev
+
+in order to check out the in-development version of ``projectname``.
+
+
+Making "Official" (Non-Snapshot) Releases
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+When you make an official release, creating source or binary distributions,
+you will need to override the tag settings from ``setup.cfg``, so that you
+don't end up registering versions like ``foobar-0.7a1.dev-r34832``.  This is
+easy to do if you are developing on the trunk and using tags or branches for
+your releases - just make the change to ``setup.cfg`` after branching or
+tagging the release, so the trunk will still produce development snapshots.
+
+Alternately, if you are not branching for releases, you can override the
+default version options on the command line, using something like::
+
+    python setup.py egg_info -Db "" sdist bdist_egg register upload
+
+The first part of this command (``egg_info -Db ""``) will override the
+configured tag information, before creating source and binary eggs, registering
+the project with PyPI, and uploading the files.  Thus, these commands will use
+the plain version from your ``setup.py``, without adding the build designation
+string.
+
+Of course, if you will be doing this a lot, you may wish to create a personal
+alias for this operation, e.g.::
+
+    python setup.py alias -u release egg_info -Db ""
+
+You can then use it like this::
+
+    python setup.py release sdist bdist_egg register upload
+
+Or of course you can create more elaborate aliases that do all of the above.
+See the sections below on the `egg_info`_ and `alias`_ commands for more ideas.
+
+
+
+Distributing Extensions compiled with Pyrex
+-------------------------------------------
+
+``setuptools`` includes transparent support for building Pyrex extensions, as
+long as you define your extensions using ``setuptools.Extension``, *not*
+``distutils.Extension``.  You must also not import anything from Pyrex in
+your setup script.
+
+If you follow these rules, you can safely list ``.pyx`` files as the source
+of your ``Extension`` objects in the setup script.  ``setuptools`` will detect
+at build time whether Pyrex is installed or not.  If it is, then ``setuptools``
+will use it.  If not, then ``setuptools`` will silently change the
+``Extension`` objects to refer to the ``.c`` counterparts of the ``.pyx``
+files, so that the normal distutils C compilation process will occur.
+
+Of course, for this to work, your source distributions must include the C
+code generated by Pyrex, as well as your original ``.pyx`` files.  This means
+that you will probably want to include current ``.c`` files in your revision
+control system, rebuilding them whenever you check changes in for the ``.pyx``
+source files.  This will ensure that people tracking your project in a revision
+control system will be able to build it even if they don't have Pyrex
+installed, and that your source releases will be similarly usable with or
+without Pyrex.
+
+
+-----------------
+Command Reference
+-----------------
+
+.. _alias:
+
+``alias`` - Define shortcuts for commonly used commands
+=======================================================
+
+Sometimes, you need to use the same commands over and over, but you can't
+necessarily set them as defaults.  For example, if you produce both development
+snapshot releases and "stable" releases of a project, you may want to put
+the distributions in different places, or use different ``egg_info`` tagging
+options, etc.  In these cases, it doesn't make sense to set the options in
+a distutils configuration file, because the values of the options changed based
+on what you're trying to do.
+
+Setuptools therefore allows you to define "aliases" - shortcut names for
+an arbitrary string of commands and options, using ``setup.py alias aliasname
+expansion``, where aliasname is the name of the new alias, and the remainder of
+the command line supplies its expansion.  For example, this command defines
+a sitewide alias called "daily", that sets various ``egg_info`` tagging
+options::
+
+    setup.py alias --global-config daily egg_info --tag-build=development
+
+Once the alias is defined, it can then be used with other setup commands,
+e.g.::
+
+    setup.py daily bdist_egg        # generate a daily-build .egg file
+    setup.py daily sdist            # generate a daily-build source distro
+    setup.py daily sdist bdist_egg  # generate both
+
+The above commands are interpreted as if the word ``daily`` were replaced with
+``egg_info --tag-build=development``.
+
+Note that setuptools will expand each alias *at most once* in a given command
+line.  This serves two purposes.  First, if you accidentally create an alias
+loop, it will have no effect; you'll instead get an error message about an
+unknown command.  Second, it allows you to define an alias for a command, that
+uses that command.  For example, this (project-local) alias::
+
+    setup.py alias bdist_egg bdist_egg rotate -k1 -m.egg
+
+redefines the ``bdist_egg`` command so that it always runs the ``rotate``
+command afterwards to delete all but the newest egg file.  It doesn't loop
+indefinitely on ``bdist_egg`` because the alias is only expanded once when
+used.
+
+You can remove a defined alias with the ``--remove`` (or ``-r``) option, e.g.::
+
+    setup.py alias --global-config --remove daily
+
+would delete the "daily" alias we defined above.
+
+Aliases can be defined on a project-specific, per-user, or sitewide basis.  The
+default is to define or remove a project-specific alias, but you can use any of
+the `configuration file options`_ (listed under the `saveopts`_ command, below)
+to determine which distutils configuration file an aliases will be added to
+(or removed from).
+
+Note that if you omit the "expansion" argument to the ``alias`` command,
+you'll get output showing that alias' current definition (and what
+configuration file it's defined in).  If you omit the alias name as well,
+you'll get a listing of all current aliases along with their configuration
+file locations.
+
+
+``bdist_egg`` - Create a Python Egg for the project
+===================================================
+
+This command generates a Python Egg (``.egg`` file) for the project.  Python
+Eggs are the preferred binary distribution format for EasyInstall, because they
+are cross-platform (for "pure" packages), directly importable, and contain
+project metadata including scripts and information about the project's
+dependencies.  They can be simply downloaded and added to ``sys.path``
+directly, or they can be placed in a directory on ``sys.path`` and then
+automatically discovered by the egg runtime system.
+
+This command runs the `egg_info`_ command (if it hasn't already run) to update
+the project's metadata (``.egg-info``) directory.  If you have added any extra
+metadata files to the ``.egg-info`` directory, those files will be included in
+the new egg file's metadata directory, for use by the egg runtime system or by
+any applications or frameworks that use that metadata.
+
+You won't usually need to specify any special options for this command; just
+use ``bdist_egg`` and you're done.  But there are a few options that may
+be occasionally useful:
+
+``--dist-dir=DIR, -d DIR``
+    Set the directory where the ``.egg`` file will be placed.  If you don't
+    supply this, then the ``--dist-dir`` setting of the ``bdist`` command
+    will be used, which is usually a directory named ``dist`` in the project
+    directory.
+
+``--plat-name=PLATFORM, -p PLATFORM``
+    Set the platform name string that will be embedded in the egg's filename
+    (assuming the egg contains C extensions).  This can be used to override
+    the distutils default platform name with something more meaningful.  Keep
+    in mind, however, that the egg runtime system expects to see eggs with
+    distutils platform names, so it may ignore or reject eggs with non-standard
+    platform names.  Similarly, the EasyInstall program may ignore them when
+    searching web pages for download links.  However, if you are
+    cross-compiling or doing some other unusual things, you might find a use
+    for this option.
+
+``--exclude-source-files``
+    Don't include any modules' ``.py`` files in the egg, just compiled Python,
+    C, and data files.  (Note that this doesn't affect any ``.py`` files in the
+    EGG-INFO directory or its subdirectories, since for example there may be
+    scripts with a ``.py`` extension which must still be retained.)  We don't
+    recommend that you use this option except for packages that are being
+    bundled for proprietary end-user applications, or for "embedded" scenarios
+    where space is at an absolute premium.  On the other hand, if your package
+    is going to be installed and used in compressed form, you might as well
+    exclude the source because Python's ``traceback`` module doesn't currently
+    understand how to display zipped source code anyway, or how to deal with
+    files that are in a different place from where their code was compiled.
+
+There are also some options you will probably never need, but which are there
+because they were copied from similar ``bdist`` commands used as an example for
+creating this one.  They may be useful for testing and debugging, however,
+which is why we kept them:
+
+``--keep-temp, -k``
+    Keep the contents of the ``--bdist-dir`` tree around after creating the
+    ``.egg`` file.
+
+``--bdist-dir=DIR, -b DIR``
+    Set the temporary directory for creating the distribution.  The entire
+    contents of this directory are zipped to create the ``.egg`` file, after
+    running various installation commands to copy the package's modules, data,
+    and extensions here.
+
+``--skip-build``
+    Skip doing any "build" commands; just go straight to the
+    install-and-compress phases.
+
+
+.. _develop:
+
+``develop`` - Deploy the project source in "Development Mode"
+=============================================================
+
+This command allows you to deploy your project's source for use in one or more
+"staging areas" where it will be available for importing.  This deployment is
+done in such a way that changes to the project source are immediately available
+in the staging area(s), without needing to run a build or install step after
+each change.
+
+The ``develop`` command works by creating an ``.egg-link`` file (named for the
+project) in the given staging area.  If the staging area is Python's
+``site-packages`` directory, it also updates an ``easy-install.pth`` file so
+that the project is on ``sys.path`` by default for all programs run using that
+Python installation.
+
+The ``develop`` command also installs wrapper scripts in the staging area (or
+a separate directory, as specified) that will ensure the project's dependencies
+are available on ``sys.path`` before running the project's source scripts.
+And, it ensures that any missing project dependencies are available in the
+staging area, by downloading and installing them if necessary.
+
+Last, but not least, the ``develop`` command invokes the ``build_ext -i``
+command to ensure any C extensions in the project have been built and are
+up-to-date, and the ``egg_info`` command to ensure the project's metadata is
+updated (so that the runtime and wrappers know what the project's dependencies
+are).  If you make any changes to the project's setup script or C extensions,
+you should rerun the ``develop`` command against all relevant staging areas to
+keep the project's scripts, metadata and extensions up-to-date.  Most other
+kinds of changes to your project should not require any build operations or
+rerunning ``develop``, but keep in mind that even minor changes to the setup
+script (e.g. changing an entry point definition) require you to re-run the
+``develop`` or ``test`` commands to keep the distribution updated.
+
+Here are some of the options that the ``develop`` command accepts.  Note that
+they affect the project's dependencies as well as the project itself, so if you
+have dependencies that need to be installed and you use ``--exclude-scripts``
+(for example), the dependencies' scripts will not be installed either!  For
+this reason, you may want to use EasyInstall to install the project's
+dependencies before using the ``develop`` command, if you need finer control
+over the installation options for dependencies.
+
+``--uninstall, -u``
+    Un-deploy the current project.  You may use the ``--install-dir`` or ``-d``
+    option to designate the staging area.  The created ``.egg-link`` file will
+    be removed, if present and it is still pointing to the project directory.
+    The project directory will be removed from ``easy-install.pth`` if the
+    staging area is Python's ``site-packages`` directory.
+
+    Note that this option currently does *not* uninstall script wrappers!  You
+    must uninstall them yourself, or overwrite them by using EasyInstall to
+    activate a different version of the package.  You can also avoid installing
+    script wrappers in the first place, if you use the ``--exclude-scripts``
+    (aka ``-x``) option when you run ``develop`` to deploy the project.
+
+``--multi-version, -m``
+    "Multi-version" mode. Specifying this option prevents ``develop`` from
+    adding an ``easy-install.pth`` entry for the project(s) being deployed, and
+    if an entry for any version of a project already exists, the entry will be
+    removed upon successful deployment.  In multi-version mode, no specific
+    version of the package is available for importing, unless you use
+    ``pkg_resources.require()`` to put it on ``sys.path``, or you are running
+    a wrapper script generated by ``setuptools`` or EasyInstall.  (In which
+    case the wrapper script calls ``require()`` for you.)
+
+    Note that if you install to a directory other than ``site-packages``,
+    this option is automatically in effect, because ``.pth`` files can only be
+    used in ``site-packages`` (at least in Python 2.3 and 2.4). So, if you use
+    the ``--install-dir`` or ``-d`` option (or they are set via configuration
+    file(s)) your project and its dependencies will be deployed in multi-
+    version mode.
+
+``--install-dir=DIR, -d DIR``
+    Set the installation directory (staging area).  If this option is not
+    directly specified on the command line or in a distutils configuration
+    file, the distutils default installation location is used.  Normally, this
+    will be the ``site-packages`` directory, but if you are using distutils
+    configuration files, setting things like ``prefix`` or ``install_lib``,
+    then those settings are taken into account when computing the default
+    staging area.
+
+``--script-dir=DIR, -s DIR``
+    Set the script installation directory.  If you don't supply this option
+    (via the command line or a configuration file), but you *have* supplied
+    an ``--install-dir`` (via command line or config file), then this option
+    defaults to the same directory, so that the scripts will be able to find
+    their associated package installation.  Otherwise, this setting defaults
+    to the location where the distutils would normally install scripts, taking
+    any distutils configuration file settings into account.
+
+``--exclude-scripts, -x``
+    Don't deploy script wrappers.  This is useful if you don't want to disturb
+    existing versions of the scripts in the staging area.
+
+``--always-copy, -a``
+    Copy all needed distributions to the staging area, even if they
+    are already present in another directory on ``sys.path``.  By default, if
+    a requirement can be met using a distribution that is already available in
+    a directory on ``sys.path``, it will not be copied to the staging area.
+
+``--egg-path=DIR``
+    Force the generated ``.egg-link`` file to use a specified relative path
+    to the source directory.  This can be useful in circumstances where your
+    installation directory is being shared by code running under multiple
+    platforms (e.g. Mac and Windows) which have different absolute locations
+    for the code under development, but the same *relative* locations with
+    respect to the installation directory.  If you use this option when
+    installing, you must supply the same relative path when uninstalling.
+
+In addition to the above options, the ``develop`` command also accepts all of
+the same options accepted by ``easy_install``.  If you've configured any
+``easy_install`` settings in your ``setup.cfg`` (or other distutils config
+files), the ``develop`` command will use them as defaults, unless you override
+them in a ``[develop]`` section or on the command line.
+
+
+``easy_install`` - Find and install packages
+============================================
+
+This command runs the `EasyInstall tool
+<easy_install.html>`_ for you.  It is exactly
+equivalent to running the ``easy_install`` command.  All command line arguments
+following this command are consumed and not processed further by the distutils,
+so this must be the last command listed on the command line.  Please see
+the EasyInstall documentation for the options reference and usage examples.
+Normally, there is no reason to use this command via the command line, as you
+can just use ``easy_install`` directly.  It's only listed here so that you know
+it's a distutils command, which means that you can:
+
+* create command aliases that use it,
+* create distutils extensions that invoke it as a subcommand, and
+* configure options for it in your ``setup.cfg`` or other distutils config
+  files.
+
+
+.. _egg_info:
+
+``egg_info`` - Create egg metadata and set build tags
+=====================================================
+
+This command performs two operations: it updates a project's ``.egg-info``
+metadata directory (used by the ``bdist_egg``, ``develop``, and ``test``
+commands), and it allows you to temporarily change a project's version string,
+to support "daily builds" or "snapshot" releases.  It is run automatically by
+the ``sdist``, ``bdist_egg``, ``develop``, ``register``, and ``test`` commands
+in order to update the project's metadata, but you can also specify it
+explicitly in order to temporarily change the project's version string while
+executing other commands.  (It also generates the``.egg-info/SOURCES.txt``
+manifest file, which is used when you are building source distributions.)
+
+In addition to writing the core egg metadata defined by ``setuptools`` and
+required by ``pkg_resources``, this command can be extended to write other
+metadata files as well, by defining entry points in the ``egg_info.writers``
+group.  See the section on `Adding new EGG-INFO Files`_ below for more details.
+Note that using additional metadata writers may require you to include a
+``setup_requires`` argument to ``setup()`` in order to ensure that the desired
+writers are available on ``sys.path``.
+
+
+Release Tagging Options
+-----------------------
+
+The following options can be used to modify the project's version string for
+all remaining commands on the setup command line.  The options are processed
+in the order shown, so if you use more than one, the requested tags will be
+added in the following order:
+
+``--tag-build=NAME, -b NAME``
+    Append NAME to the project's version string.  Due to the way setuptools
+    processes "pre-release" version suffixes beginning with the letters "a"
+    through "e" (like "alpha", "beta", and "candidate"), you will usually want
+    to use a tag like ".build" or ".dev", as this will cause the version number
+    to be considered *lower* than the project's default version.  (If you
+    want to make the version number *higher* than the default version, you can
+    always leave off --tag-build and then use one or both of the following
+    options.)
+
+    If you have a default build tag set in your ``setup.cfg``, you can suppress
+    it on the command line using ``-b ""`` or ``--tag-build=""`` as an argument
+    to the ``egg_info`` command.
+
+``--tag-date, -d``
+    Add a date stamp of the form "-YYYYMMDD" (e.g. "-20050528") to the
+    project's version number.
+
+``--no-date, -D``
+    Don't include a date stamp in the version number.  This option is included
+    so you can override a default setting in ``setup.cfg``.
+
+
+(Note: Because these options modify the version number used for source and
+binary distributions of your project, you should first make sure that you know
+how the resulting version numbers will be interpreted by automated tools
+like EasyInstall.  See the section above on `Specifying Your Project's
+Version`_ for an explanation of pre- and post-release tags, as well as tips on
+how to choose and verify a versioning scheme for your your project.)
+
+For advanced uses, there is one other option that can be set, to change the
+location of the project's ``.egg-info`` directory.  Commands that need to find
+the project's source directory or metadata should get it from this setting:
+
+
+Other ``egg_info`` Options
+--------------------------
+
+``--egg-base=SOURCEDIR, -e SOURCEDIR``
+    Specify the directory that should contain the .egg-info directory.  This
+    should normally be the root of your project's source tree (which is not
+    necessarily the same as your project directory; some projects use a ``src``
+    or ``lib`` subdirectory as the source root).  You should not normally need
+    to specify this directory, as it is normally determined from the
+    ``package_dir`` argument to the ``setup()`` function, if any.  If there is
+    no ``package_dir`` set, this option defaults to the current directory.
+
+
+``egg_info`` Examples
+---------------------
+
+Creating a dated "nightly build" snapshot egg::
+
+    python setup.py egg_info --tag-date --tag-build=DEV bdist_egg
+
+Creating and uploading a release with no version tags, even if some default
+tags are specified in ``setup.cfg``::
+
+    python setup.py egg_info -RDb "" sdist bdist_egg register upload
+
+(Notice that ``egg_info`` must always appear on the command line *before* any
+commands that you want the version changes to apply to.)
+
+
+.. _install command:
+
+``install`` - Run ``easy_install`` or old-style installation
+============================================================
+
+The setuptools ``install`` command is basically a shortcut to run the
+``easy_install`` command on the current project.  However, for convenience
+in creating "system packages" of setuptools-based projects, you can also
+use this option:
+
+``--single-version-externally-managed``
+    This boolean option tells the ``install`` command to perform an "old style"
+    installation, with the addition of an ``.egg-info`` directory so that the
+    installed project will still have its metadata available and operate
+    normally.  If you use this option, you *must* also specify the ``--root``
+    or ``--record`` options (or both), because otherwise you will have no way
+    to identify and remove the installed files.
+
+This option is automatically in effect when ``install`` is invoked by another
+distutils command, so that commands like ``bdist_wininst`` and ``bdist_rpm``
+will create system packages of eggs.  It is also automatically in effect if
+you specify the ``--root`` option.
+
+
+``install_egg_info`` - Install an ``.egg-info`` directory in ``site-packages``
+==============================================================================
+
+Setuptools runs this command as part of ``install`` operations that use the
+``--single-version-externally-managed`` options.  You should not invoke it
+directly; it is documented here for completeness and so that distutils
+extensions such as system package builders can make use of it.  This command
+has only one option:
+
+``--install-dir=DIR, -d DIR``
+    The parent directory where the ``.egg-info`` directory will be placed.
+    Defaults to the same as the ``--install-dir`` option specified for the
+    ``install_lib`` command, which is usually the system ``site-packages``
+    directory.
+
+This command assumes that the ``egg_info`` command has been given valid options
+via the command line or ``setup.cfg``, as it will invoke the ``egg_info``
+command and use its options to locate the project's source ``.egg-info``
+directory.
+
+
+.. _rotate:
+
+``rotate`` - Delete outdated distribution files
+===============================================
+
+As you develop new versions of your project, your distribution (``dist``)
+directory will gradually fill up with older source and/or binary distribution
+files.  The ``rotate`` command lets you automatically clean these up, keeping
+only the N most-recently modified files matching a given pattern.
+
+``--match=PATTERNLIST, -m PATTERNLIST``
+    Comma-separated list of glob patterns to match.  This option is *required*.
+    The project name and ``-*`` is prepended to the supplied patterns, in order
+    to match only distributions belonging to the current project (in case you
+    have a shared distribution directory for multiple projects).  Typically,
+    you will use a glob pattern like ``.zip`` or ``.egg`` to match files of
+    the specified type.  Note that each supplied pattern is treated as a
+    distinct group of files for purposes of selecting files to delete.
+
+``--keep=COUNT, -k COUNT``
+    Number of matching distributions to keep.  For each group of files
+    identified by a pattern specified with the ``--match`` option, delete all
+    but the COUNT most-recently-modified files in that group.  This option is
+    *required*.
+
+``--dist-dir=DIR, -d DIR``
+    Directory where the distributions are.  This defaults to the value of the
+    ``bdist`` command's ``--dist-dir`` option, which will usually be the
+    project's ``dist`` subdirectory.
+
+**Example 1**: Delete all .tar.gz files from the distribution directory, except
+for the 3 most recently modified ones::
+
+    setup.py rotate --match=.tar.gz --keep=3
+
+**Example 2**: Delete all Python 2.3 or Python 2.4 eggs from the distribution
+directory, except the most recently modified one for each Python version::
+
+    setup.py rotate --match=-py2.3*.egg,-py2.4*.egg --keep=1
+
+
+.. _saveopts:
+
+``saveopts`` - Save used options to a configuration file
+========================================================
+
+Finding and editing ``distutils`` configuration files can be a pain, especially
+since you also have to translate the configuration options from command-line
+form to the proper configuration file format.  You can avoid these hassles by
+using the ``saveopts`` command.  Just add it to the command line to save the
+options you used.  For example, this command builds the project using
+the ``mingw32`` C compiler, then saves the --compiler setting as the default
+for future builds (even those run implicitly by the ``install`` command)::
+
+    setup.py build --compiler=mingw32 saveopts
+
+The ``saveopts`` command saves all options for every command specified on the
+command line to the project's local ``setup.cfg`` file, unless you use one of
+the `configuration file options`_ to change where the options are saved.  For
+example, this command does the same as above, but saves the compiler setting
+to the site-wide (global) distutils configuration::
+
+    setup.py build --compiler=mingw32 saveopts -g
+
+Note that it doesn't matter where you place the ``saveopts`` command on the
+command line; it will still save all the options specified for all commands.
+For example, this is another valid way to spell the last example::
+
+    setup.py saveopts -g build --compiler=mingw32
+
+Note, however, that all of the commands specified are always run, regardless of
+where ``saveopts`` is placed on the command line.
+
+
+Configuration File Options
+--------------------------
+
+Normally, settings such as options and aliases are saved to the project's
+local ``setup.cfg`` file.  But you can override this and save them to the
+global or per-user configuration files, or to a manually-specified filename.
+
+``--global-config, -g``
+    Save settings to the global ``distutils.cfg`` file inside the ``distutils``
+    package directory.  You must have write access to that directory to use
+    this option.  You also can't combine this option with ``-u`` or ``-f``.
+
+``--user-config, -u``
+    Save settings to the current user's ``~/.pydistutils.cfg`` (POSIX) or
+    ``$HOME/pydistutils.cfg`` (Windows) file.  You can't combine this option
+    with ``-g`` or ``-f``.
+
+``--filename=FILENAME, -f FILENAME``
+    Save settings to the specified configuration file to use.  You can't
+    combine this option with ``-g`` or ``-u``.  Note that if you specify a
+    non-standard filename, the ``distutils`` and ``setuptools`` will not
+    use the file's contents.  This option is mainly included for use in
+    testing.
+
+These options are used by other ``setuptools`` commands that modify
+configuration files, such as the `alias`_ and `setopt`_ commands.
+
+
+.. _setopt:
+
+``setopt`` - Set a distutils or setuptools option in a config file
+==================================================================
+
+This command is mainly for use by scripts, but it can also be used as a quick
+and dirty way to change a distutils configuration option without having to
+remember what file the options are in and then open an editor.
+
+**Example 1**.  Set the default C compiler to ``mingw32`` (using long option
+names)::
+
+    setup.py setopt --command=build --option=compiler --set-value=mingw32
+
+**Example 2**.  Remove any setting for the distutils default package
+installation directory (short option names)::
+
+    setup.py setopt -c install -o install_lib -r
+
+
+Options for the ``setopt`` command:
+
+``--command=COMMAND, -c COMMAND``
+    Command to set the option for.  This option is required.
+
+``--option=OPTION, -o OPTION``
+    The name of the option to set.  This option is required.
+
+``--set-value=VALUE, -s VALUE``
+    The value to set the option to.  Not needed if ``-r`` or ``--remove`` is
+    set.
+
+``--remove, -r``
+    Remove (unset) the option, instead of setting it.
+
+In addition to the above options, you may use any of the `configuration file
+options`_ (listed under the `saveopts`_ command, above) to determine which
+distutils configuration file the option will be added to (or removed from).
+
+
+.. _test:
+
+``test`` - Build package and run a unittest suite
+=================================================
+
+When doing test-driven development, or running automated builds that need
+testing before they are deployed for downloading or use, it's often useful
+to be able to run a project's unit tests without actually deploying the project
+anywhere, even using the ``develop`` command.  The ``test`` command runs a
+project's unit tests without actually deploying it, by temporarily putting the
+project's source on ``sys.path``, after first running ``build_ext -i`` and
+``egg_info`` to ensure that any C extensions and project metadata are
+up-to-date.
+
+To use this command, your project's tests must be wrapped in a ``unittest``
+test suite by either a function, a ``TestCase`` class or method, or a module
+or package containing ``TestCase`` classes.  If the named suite is a module,
+and the module has an ``additional_tests()`` function, it is called and the
+result (which must be a ``unittest.TestSuite``) is added to the tests to be
+run.  If the named suite is a package, any submodules and subpackages are
+recursively added to the overall test suite.  (Note: if your project specifies
+a ``test_loader``, the rules for processing the chosen ``test_suite`` may
+differ; see the `test_loader`_ documentation for more details.)
+
+Note that many test systems including ``doctest`` support wrapping their
+non-``unittest`` tests in ``TestSuite`` objects.  So, if you are using a test
+package that does not support this, we suggest you encourage its developers to
+implement test suite support, as this is a convenient and standard way to
+aggregate a collection of tests to be run under a common test harness.
+
+By default, tests will be run in the "verbose" mode of the ``unittest``
+package's text test runner, but you can get the "quiet" mode (just dots) if
+you supply the ``-q`` or ``--quiet`` option, either as a global option to
+the setup script (e.g. ``setup.py -q test``) or as an option for the ``test``
+command itself (e.g. ``setup.py test -q``).  There is one other option
+available:
+
+``--test-suite=NAME, -s NAME``
+    Specify the test suite (or module, class, or method) to be run
+    (e.g. ``some_module.test_suite``).  The default for this option can be
+    set by giving a ``test_suite`` argument to the ``setup()`` function, e.g.::
+
+        setup(
+            # ...
+            test_suite="my_package.tests.test_all"
+        )
+
+    If you did not set a ``test_suite`` in your ``setup()`` call, and do not
+    provide a ``--test-suite`` option, an error will occur.
+
+
+.. _upload:
+
+``upload`` - Upload source and/or egg distributions to PyPI
+===========================================================
+
+The ``upload`` command is implemented and `documented
+<https://docs.python.org/3.1/distutils/uploading.html>`_
+in distutils.
+
+Setuptools augments the ``upload`` command with support
+for `keyring <https://pypi.org/project/keyring/>`_,
+allowing the password to be stored in a secure
+location and not in plaintext in the .pypirc file. To use
+keyring, first install keyring and set the password for
+the relevant repository, e.g.::
+
+    python -m keyring set <repository> <username>
+    Password for '<username>' in '<repository>': ********
+
+Then, in .pypirc, set the repository configuration as normal,
+but omit the password. Thereafter, uploads will use the
+password from the keyring.
+
+New in 20.1: Added keyring support.
+
+
+-----------------------------------------
+Configuring setup() using setup.cfg files
+-----------------------------------------
+
+.. note:: New in 30.3.0 (8 Dec 2016).
+
+.. important::
+    A ``setup.py`` file containing a ``setup()`` function call is still
+    required even if your configuration resides in ``setup.cfg``.
+
+``Setuptools`` allows using configuration files (usually :file:`setup.cfg`)
+to define a package’s metadata and other options that are normally supplied
+to the ``setup()`` function.
+
+This approach not only allows automation scenarios but also reduces
+boilerplate code in some cases.
+
+.. note::
+
+    This implementation has limited compatibility with the distutils2-like
+    ``setup.cfg`` sections used by the ``pbr`` and ``d2to1`` packages.
+
+    Namely: only metadata-related keys from ``metadata`` section are supported
+    (except for ``description-file``); keys from ``files``, ``entry_points``
+    and ``backwards_compat`` are not supported.
+
+
+.. code-block:: ini
+
+    [metadata]
+    name = my_package
+    version = attr: src.VERSION
+    description = My package description
+    long_description = file: README.rst, CHANGELOG.rst, LICENSE.rst
+    keywords = one, two
+    license = BSD 3-Clause License
+    classifiers =
+        Framework :: Django
+        Programming Language :: Python :: 3
+        Programming Language :: Python :: 3.5
+
+    [options]
+    zip_safe = False
+    include_package_data = True
+    packages = find:
+    scripts =
+      bin/first.py
+      bin/second.py
+
+    [options.package_data]
+    * = *.txt, *.rst
+    hello = *.msg
+
+    [options.extras_require]
+    pdf = ReportLab>=1.2; RXP
+    rest = docutils>=0.3; pack ==1.1, ==1.3
+
+    [options.packages.find]
+    exclude =
+        src.subpackage1
+        src.subpackage2
+
+
+Metadata and options are set in the config sections of the same name.
+
+* Keys are the same as the keyword arguments one provides to the ``setup()``
+  function.
+
+* Complex values can be written comma-separated or placed one per line
+  in *dangling* config values. The following are equivalent:
+
+  .. code-block:: ini
+
+      [metadata]
+      keywords = one, two
+
+      [metadata]
+      keywords =
+        one
+        two
+
+* In some cases, complex values can be provided in dedicated subsections for
+  clarity.
+
+* Some keys allow ``file:``, ``attr:``, and ``find:`` directives in order to
+  cover common usecases.
+
+* Unknown keys are ignored.
+
+
+Specifying values
+=================
+
+Some values are treated as simple strings, some allow more logic.
+
+Type names used below:
+
+* ``str`` - simple string
+* ``list-comma`` - dangling list or string of comma-separated values
+* ``list-semi`` - dangling list or string of semicolon-separated values
+* ``bool`` - ``True`` is 1, yes, true
+* ``dict`` - list-comma where keys are separated from values by ``=``
+* ``section`` - values are read from a dedicated (sub)section
+
+
+Special directives:
+
+* ``attr:`` - Value is read from a module attribute.  ``attr:`` supports
+  callables and iterables; unsupported types are cast using ``str()``.
+* ``file:`` - Value is read from a list of files and then concatenated
+
+
+.. note::
+    The ``file:`` directive is sandboxed and won't reach anything outside
+    the directory containing ``setup.py``.
+
+
+Metadata
+--------
+
+.. note::
+    The aliases given below are supported for compatibility reasons,
+    but their use is not advised.
+
+==============================  =================  =====
+Key                             Aliases            Type
+==============================  =================  =====
+name                                               str
+version                                            attr:, str
+url                             home-page          str
+download_url                    download-url       str
+project_urls                                       dict
+author                                             str
+author_email                    author-email       str
+maintainer                                         str
+maintainer_email                maintainer-email   str
+classifiers                     classifier         file:, list-comma
+license                                            file:, str
+description                     summary            file:, str
+long_description                long-description   file:, str
+long_description_content_type                      str
+keywords                                           list-comma
+platforms                       platform           list-comma
+provides                                           list-comma
+requires                                           list-comma
+obsoletes                                          list-comma
+==============================  =================  =====
+
+
+Options
+-------
+
+=======================  =====
+Key                      Type
+=======================  =====
+zip_safe                 bool
+setup_requires           list-semi
+install_requires         list-semi
+extras_require           section
+python_requires          str
+entry_points             file:, section
+use_2to3                 bool
+use_2to3_fixers          list-comma
+use_2to3_exclude_fixers  list-comma
+convert_2to3_doctests    list-comma
+scripts                  list-comma
+eager_resources          list-comma
+dependency_links         list-comma
+tests_require            list-semi
+include_package_data     bool
+packages                 find:, list-comma
+package_dir              dict
+package_data             section
+exclude_package_data     section
+namespace_packages       list-comma
+py_modules               list-comma
+=======================  =====
+
+.. note::
+
+    **packages** - The ``find:`` directive can be further configured
+    in a dedicated subsection ``options.packages.find``. This subsection
+    accepts the same keys as the `setuptools.find` function:
+    ``where``, ``include``, and ``exclude``.
+
+
+Configuration API
+=================
+
+Some automation tools may wish to access data from a configuration file.
+
+``Setuptools`` exposes a ``read_configuration()`` function for
+parsing ``metadata`` and ``options`` sections into a dictionary.
+
+
+.. code-block:: python
+
+    from setuptools.config import read_configuration
+
+    conf_dict = read_configuration('/home/user/dev/package/setup.cfg')
+
+
+By default, ``read_configuration()`` will read only the file provided
+in the first argument. To include values from other configuration files
+which could be in various places, set the ``find_others`` keyword argument
+to ``True``.
+
+If you have only a configuration file but not the whole package, you can still
+try to get data out of it with the help of the ``ignore_option_errors`` keyword
+argument. When it is set to ``True``, all options with errors possibly produced
+by directives, such as ``attr:`` and others, will be silently ignored.
+As a consequence, the resulting dictionary will include no such options.
+
+
+--------------------------------
+Extending and Reusing Setuptools
+--------------------------------
+
+Creating ``distutils`` Extensions
+=================================
+
+It can be hard to add new commands or setup arguments to the distutils.  But
+the ``setuptools`` package makes it a bit easier, by allowing you to distribute
+a distutils extension as a separate project, and then have projects that need
+the extension just refer to it in their ``setup_requires`` argument.
+
+With ``setuptools``, your distutils extension projects can hook in new
+commands and ``setup()`` arguments just by defining "entry points".  These
+are mappings from command or argument names to a specification of where to
+import a handler from.  (See the section on `Dynamic Discovery of Services and
+Plugins`_ above for some more background on entry points.)
+
+
+Adding Commands
+---------------
+
+You can add new ``setup`` commands by defining entry points in the
+``distutils.commands`` group.  For example, if you wanted to add a ``foo``
+command, you might add something like this to your distutils extension
+project's setup script::
+
+    setup(
+        # ...
+        entry_points={
+            "distutils.commands": [
+                "foo = mypackage.some_module:foo",
+            ],
+        },
+    )
+
+(Assuming, of course, that the ``foo`` class in ``mypackage.some_module`` is
+a ``setuptools.Command`` subclass.)
+
+Once a project containing such entry points has been activated on ``sys.path``,
+(e.g. by running "install" or "develop" with a site-packages installation
+directory) the command(s) will be available to any ``setuptools``-based setup
+scripts.  It is not necessary to use the ``--command-packages`` option or
+to monkeypatch the ``distutils.command`` package to install your commands;
+``setuptools`` automatically adds a wrapper to the distutils to search for
+entry points in the active distributions on ``sys.path``.  In fact, this is
+how setuptools' own commands are installed: the setuptools project's setup
+script defines entry points for them!
+
+
+Adding ``setup()`` Arguments
+----------------------------
+
+Sometimes, your commands may need additional arguments to the ``setup()``
+call.  You can enable this by defining entry points in the
+``distutils.setup_keywords`` group.  For example, if you wanted a ``setup()``
+argument called ``bar_baz``, you might add something like this to your
+distutils extension project's setup script::
+
+    setup(
+        # ...
+        entry_points={
+            "distutils.commands": [
+                "foo = mypackage.some_module:foo",
+            ],
+            "distutils.setup_keywords": [
+                "bar_baz = mypackage.some_module:validate_bar_baz",
+            ],
+        },
+    )
+
+The idea here is that the entry point defines a function that will be called
+to validate the ``setup()`` argument, if it's supplied.  The ``Distribution``
+object will have the initial value of the attribute set to ``None``, and the
+validation function will only be called if the ``setup()`` call sets it to
+a non-None value.  Here's an example validation function::
+
+    def assert_bool(dist, attr, value):
+        """Verify that value is True, False, 0, or 1"""
+        if bool(value) != value:
+            raise DistutilsSetupError(
+                "%r must be a boolean value (got %r)" % (attr,value)
+            )
+
+Your function should accept three arguments: the ``Distribution`` object,
+the attribute name, and the attribute value.  It should raise a
+``DistutilsSetupError`` (from the ``distutils.errors`` module) if the argument
+is invalid.  Remember, your function will only be called with non-None values,
+and the default value of arguments defined this way is always None.  So, your
+commands should always be prepared for the possibility that the attribute will
+be ``None`` when they access it later.
+
+If more than one active distribution defines an entry point for the same
+``setup()`` argument, *all* of them will be called.  This allows multiple
+distutils extensions to define a common argument, as long as they agree on
+what values of that argument are valid.
+
+Also note that as with commands, it is not necessary to subclass or monkeypatch
+the distutils ``Distribution`` class in order to add your arguments; it is
+sufficient to define the entry points in your extension, as long as any setup
+script using your extension lists your project in its ``setup_requires``
+argument.
+
+
+Adding new EGG-INFO Files
+-------------------------
+
+Some extensible applications or frameworks may want to allow third parties to
+develop plugins with application or framework-specific metadata included in
+the plugins' EGG-INFO directory, for easy access via the ``pkg_resources``
+metadata API.  The easiest way to allow this is to create a distutils extension
+to be used from the plugin projects' setup scripts (via ``setup_requires``)
+that defines a new setup keyword, and then uses that data to write an EGG-INFO
+file when the ``egg_info`` command is run.
+
+The ``egg_info`` command looks for extension points in an ``egg_info.writers``
+group, and calls them to write the files.  Here's a simple example of a
+distutils extension defining a setup argument ``foo_bar``, which is a list of
+lines that will be written to ``foo_bar.txt`` in the EGG-INFO directory of any
+project that uses the argument::
+
+    setup(
+        # ...
+        entry_points={
+            "distutils.setup_keywords": [
+                "foo_bar = setuptools.dist:assert_string_list",
+            ],
+            "egg_info.writers": [
+                "foo_bar.txt = setuptools.command.egg_info:write_arg",
+            ],
+        },
+    )
+
+This simple example makes use of two utility functions defined by setuptools
+for its own use: a routine to validate that a setup keyword is a sequence of
+strings, and another one that looks up a setup argument and writes it to
+a file.  Here's what the writer utility looks like::
+
+    def write_arg(cmd, basename, filename):
+        argname = os.path.splitext(basename)[0]
+        value = getattr(cmd.distribution, argname, None)
+        if value is not None:
+            value = '\n'.join(value) + '\n'
+        cmd.write_or_delete_file(argname, filename, value)
+
+As you can see, ``egg_info.writers`` entry points must be a function taking
+three arguments: a ``egg_info`` command instance, the basename of the file to
+write (e.g. ``foo_bar.txt``), and the actual full filename that should be
+written to.
+
+In general, writer functions should honor the command object's ``dry_run``
+setting when writing files, and use the ``distutils.log`` object to do any
+console output.  The easiest way to conform to this requirement is to use
+the ``cmd`` object's ``write_file()``, ``delete_file()``, and
+``write_or_delete_file()`` methods exclusively for your file operations.  See
+those methods' docstrings for more details.
+
+
+Adding Support for Revision Control Systems
+-------------------------------------------------
+
+If the files you want to include in the source distribution are tracked using
+Git, Mercurial or SVN, you can use the following packages to achieve that:
+
+- Git and Mercurial: `setuptools_scm <https://pypi.org/project/setuptools_scm/>`_
+- SVN: `setuptools_svn <https://pypi.org/project/setuptools_svn/>`_
+
+If you would like to create a plugin for ``setuptools`` to find files tracked
+by another revision control system, you can do so by adding an entry point to
+the ``setuptools.file_finders`` group.  The entry point should be a function
+accepting a single directory name, and should yield all the filenames within
+that directory (and any subdirectories thereof) that are under revision
+control.
+
+For example, if you were going to create a plugin for a revision control system
+called "foobar", you would write a function something like this:
+
+.. code-block:: python
+
+    def find_files_for_foobar(dirname):
+        # loop to yield paths that start with `dirname`
+
+And you would register it in a setup script using something like this::
+
+    entry_points={
+        "setuptools.file_finders": [
+            "foobar = my_foobar_module:find_files_for_foobar",
+        ]
+    }
+
+Then, anyone who wants to use your plugin can simply install it, and their
+local setuptools installation will be able to find the necessary files.
+
+It is not necessary to distribute source control plugins with projects that
+simply use the other source control system, or to specify the plugins in
+``setup_requires``.  When you create a source distribution with the ``sdist``
+command, setuptools automatically records what files were found in the
+``SOURCES.txt`` file.  That way, recipients of source distributions don't need
+to have revision control at all.  However, if someone is working on a package
+by checking out with that system, they will need the same plugin(s) that the
+original author is using.
+
+A few important points for writing revision control file finders:
+
+* Your finder function MUST return relative paths, created by appending to the
+  passed-in directory name.  Absolute paths are NOT allowed, nor are relative
+  paths that reference a parent directory of the passed-in directory.
+
+* Your finder function MUST accept an empty string as the directory name,
+  meaning the current directory.  You MUST NOT convert this to a dot; just
+  yield relative paths.  So, yielding a subdirectory named ``some/dir`` under
+  the current directory should NOT be rendered as ``./some/dir`` or
+  ``/somewhere/some/dir``, but *always* as simply ``some/dir``
+
+* Your finder function SHOULD NOT raise any errors, and SHOULD deal gracefully
+  with the absence of needed programs (i.e., ones belonging to the revision
+  control system itself.  It *may*, however, use ``distutils.log.warn()`` to
+  inform the user of the missing program(s).
+
+
+Subclassing ``Command``
+-----------------------
+
+Sorry, this section isn't written yet, and neither is a lot of what's below
+this point.
+
+XXX
+
+
+Reusing ``setuptools`` Code
+===========================
+
+``ez_setup``
+------------
+
+XXX
+
+
+``setuptools.archive_util``
+---------------------------
+
+XXX
+
+
+``setuptools.sandbox``
+----------------------
+
+XXX
+
+
+``setuptools.package_index``
+----------------------------
+
+XXX
+
+
+Mailing List and Bug Tracker
+============================
+
+Please use the `distutils-sig mailing list`_ for questions and discussion about
+setuptools, and the `setuptools bug tracker`_ ONLY for issues you have
+confirmed via the list are actual bugs, and which you have reduced to a minimal
+set of steps to reproduce.
+
+.. _distutils-sig mailing list: http://mail.python.org/pipermail/distutils-sig/
+.. _setuptools bug tracker: https://github.com/pypa/setuptools/