6 files changed, 940 insertions, 940 deletions

diff --git a/doc/source/add_argument.rst b/doc/source/add_argument.rst
index 8d6b35c..bc7a2a3 100644
--- a/doc/source/add_argument.rst
+++ b/doc/source/add_argument.rst
@@ -1,421 +1,421 @@
-The add_argument() method

-=========================

-

-.. method:: add_argument(name or flags..., [action], [nargs], [const], [default], [type], [choices], [required], [help], [metavar], [dest])

-

-   Define how a single command line argument should be parsed. Each parameter has its own more detailed description below, but in short they are:

-   

-   * `name or flags`_ - Either a name or a list of option strings, e.g. ``foo`` or ``-f, --foo``

-   * action_ - The basic type of action to be taken when this argument is encountered at the command-line.

-   * nargs_ - The number of command-line arguments that should be consumed.

-   * const_ - A constant value required by some action_ and nargs_ selections.

-   * default_ - The value produced if the argument is absent from the command-line.

-   * type_ - The type to which the command-line arg should be converted.

-   * choices_ - A container of the allowable values for the argument.

-   * required_ - Whether or not the command-line option may be omitted (optionals only).

-   * help_ - A brief description of what the argument does.

-   * metavar_ - A name for the argument in usage messages.

-   * dest_ - The name of the attribute to be added to the object returned by :meth:`parse_args`.

-   

-   The following sections describe how each of these are used.

-

-name or flags

--------------

-

-The :meth:`add_argument` method needs to know whether you're expecting an optional argument, e.g. ``-f`` or ``--foo``, or a positional argument, e.g. a list of filenames. The first arguments passed to :meth:`add_argument` must therefore be either a series of flags, or a simple argument name. For example, an optional argument could be created like::

-

-  >>> parser.add_argument('-f', '--foo')

-

-while a positional argument could be created like::

-

-  >>> parser.add_argument('bar')

-

-When :meth:`parse_args` is called, optional arguments will be identified by the ``-`` prefix, and the remaining arguments will be assumed to be positional::

-

-  >>> parser = argparse.ArgumentParser(prog='PROG')

-  >>> parser.add_argument('-f', '--foo')

-  >>> parser.add_argument('bar')

-  >>> parser.parse_args(['BAR'])

-  Namespace(bar='BAR', foo=None)

-  >>> parser.parse_args(['BAR', '--foo', 'FOO'])

-  Namespace(bar='BAR', foo='FOO')

-  >>> parser.parse_args(['--foo', 'FOO'])

-  usage: PROG [-h] [-f FOO] bar

-  PROG: error: too few arguments

-

-action

-------

-

-:class:`ArgumentParser` objects associate command-line args with actions.  These actions can do just about anything with the command-line args associated with them, though most actions simply add an attribute to the object returned by :meth:`parse_args`.  When you specify a new argument using the :meth:`add_argument` method, you can indicate how the command-line args should be handled by specifying the ``action`` keyword argument. The supported actions are:

-

-* ``'store'`` - This just stores the argument's value. This is the default action. For example::

-

-    >>> parser = argparse.ArgumentParser()

-    >>> parser.add_argument('--foo')

-    >>> parser.parse_args('--foo 1'.split())

-    Namespace(foo='1')

-

-* ``'store_const'`` - This stores the value specified by the const_ keyword argument. Note that the const_ keyword argument defaults to ``None``, so you'll almost always need to provide a value for it. The ``'store_const'`` action is most commonly used with optional arguments that specify some sort of flag.  For example::

-

-    >>> parser = argparse.ArgumentParser()

-    >>> parser.add_argument('--foo', action='store_const', const=42)

-    >>> parser.parse_args('--foo'.split())

-    Namespace(foo=42)

-

-* ``'store_true'`` and ``'store_false'`` - These store the values ``True`` and ``False`` respectively.  These are basically special cases of ``'store_const'``.  For example::

-

-    >>> parser = argparse.ArgumentParser()

-    >>> parser.add_argument('--foo', action='store_true')

-    >>> parser.add_argument('--bar', action='store_false')

-    >>> parser.parse_args('--foo --bar'.split())

-    Namespace(bar=False, foo=True)

-

-* ``'append'`` - This stores a list, and appends each argument value to the list.  This is useful when you want to allow an option to be specified multiple times.  Example usage::

-

-    >>> parser = argparse.ArgumentParser()

-    >>> parser.add_argument('--foo', action='append')

-    >>> parser.parse_args('--foo 1 --foo 2'.split())

-    Namespace(foo=['1', '2'])

-

-* ``'append_const'`` - This stores a list, and appends the value specified by the const_ keyword argument to the list.  Note that the const_ keyword argument defaults to ``None``, so you'll almost always need to provide a value for it.  The ``'append_const'`` action is typically useful when you want multiple arguments to store constants to the same list, for example::

-

-    >>> parser = argparse.ArgumentParser()

-    >>> parser.add_argument('--str', dest='types', action='append_const', const=str)

-    >>> parser.add_argument('--int', dest='types', action='append_const', const=int)

-    >>> parser.parse_args('--str --int'.split())

-    Namespace(types=[<type 'str'>, <type 'int'>])

-

-You can also specify an arbitrary action by passing an object that implements the Action API.  The easiest way to do this is to extend ``argparse.Action``, supplying an appropriate ``__call__`` method.  The ``__call__`` method accepts four parameters:

-

-* ``parser`` - The ArgumentParser object which contains this action.

-* ``namespace`` - The namespace object that will be returned by :meth:`parse_args`. Most actions add an attribute to this object.

-* ``values`` - The associated command-line args, with any type-conversions applied.  (Type-conversions are specified with the type_ keyword argument to :meth:`add_argument`.

-* ``option_string`` - The option string that was used to invoke this action. The ``option_string`` argument is optional, and will be absent if the action is associated with a positional argument.

-

-So for example::

-

-  >>> class FooAction(argparse.Action):

-  ...     def __call__(self, parser, namespace, values, option_string=None):

-  ...     print '%r %r %r' % (namespace, values, option_string)

-  ...     setattr(namespace, self.dest, values)

-  ...     

-  >>> parser = argparse.ArgumentParser()

-  >>> parser.add_argument('--foo', action=FooAction)

-  >>> parser.add_argument('bar', action=FooAction)

-  >>> args = parser.parse_args('1 --foo 2'.split())

-  Namespace(bar=None, foo=None) '1' None

-  Namespace(bar='1', foo=None) '2' '--foo'

-  >>> args

-  Namespace(bar='1', foo='2')

-

-

-nargs

------

-

-ArgumentParser objects usually associate a single command-line argument with a single action to be taken.  In the situations where you'd like to associate a different number of command-line arguments with a single action, you can use the ``nargs`` keyword argument to :meth:`add_argument`. The supported values are:

-

-* N (an integer). N args from the command-line will be gathered together into a list.  For example::

-

-    >>> parser = argparse.ArgumentParser()

-    >>> parser.add_argument('--foo', nargs=2)

-    >>> parser.add_argument('bar', nargs=1)

-    >>> parser.parse_args('c --foo a b'.split())

-    Namespace(bar=['c'], foo=['a', 'b'])

-

-  Note that ``nargs=1`` produces a list of one item.  This is different from the default, in which the item is produced by itself.

-

-* ``'?'``. One arg will be consumed from the command-line if possible, and produced as a single item.  If no command-line arg is present, the value from default_ will be produced.  Note that for optional arguments, there is an additional case - the option string is present but not followed by a command-line arg.  In this case the value from const_ will be produced.  Some examples to illustrate this::

-

-    >>> parser = argparse.ArgumentParser()

-    >>> parser.add_argument('--foo', nargs='?', const='c', default='d')

-    >>> parser.add_argument('bar', nargs='?', default='d')

-    >>> parser.parse_args('XX --foo YY'.split())

-    Namespace(bar='XX', foo='YY')

-    >>> parser.parse_args('XX --foo'.split())

-    Namespace(bar='XX', foo='c')

-    >>> parser.parse_args(''.split())

-    Namespace(bar='d', foo='d')

-

-  One of the more common uses of ``nargs='?'`` is to allow optional input and output files::

-

-    >>> parser = argparse.ArgumentParser()

-    >>> parser.add_argument('infile', nargs='?', type=argparse.FileType('r'), default=sys.stdin)

-    >>> parser.add_argument('outfile', nargs='?', type=argparse.FileType('w'), default=sys.stdout)

-    >>> parser.parse_args(['input.txt', 'output.txt'])

-    Namespace(infile=<open file 'input.txt', mode 'r' at 0x...>, outfile=<open file 'output.txt', mode 'w' at 0x...>)

-    >>> parser.parse_args([])

-    Namespace(infile=<open file '<stdin>', mode 'r' at 0x...>, outfile=<open file '<stdout>', mode 'w' at 0x...>)

-

-* ``'*'``. All command-line args present are gathered into a list. Note that it generally doesn't make much sense to have more than one positional argument with ``nargs='*'``, but multiple optional arguments with ``nargs='*'`` is possible.  For example::

-

-    >>> parser = argparse.ArgumentParser()

-    >>> parser.add_argument('--foo', nargs='*')

-    >>> parser.add_argument('--bar', nargs='*')

-    >>> parser.add_argument('baz', nargs='*')

-    >>> parser.parse_args('a b --foo x y --bar 1 2'.split())

-    Namespace(bar=['1', '2'], baz=['a', 'b'], foo=['x', 'y'])

-

-* ``'+'``. Just like ``'*'``, all command-line args present are gathered into a list.  Additionally, an error message will be generated if there wasn't at least one command-line arg present.  For example::

-

-    >>> parser = argparse.ArgumentParser(prog='PROG')

-    >>> parser.add_argument('foo', nargs='+')

-    >>> parser.parse_args('a b'.split())

-    Namespace(foo=['a', 'b'])

-    >>> parser.parse_args(''.split())

-    usage: PROG [-h] foo [foo ...]

-    PROG: error: too few arguments

-

-If the ``nargs`` keyword argument is not provided, the number of args consumed is determined by the action_. Generally this means a single command-line arg will be consumed and a single item (not a list) will be produced.

-

-

-const

------

-

-The ``const`` argument of :meth:`add_argument` is used to hold constant values that are not read from the command line but are required for the various ArgumentParser actions.  The two most common uses of it are:

-

-* When :meth:`add_argument` is called with ``action='store_const'`` or ``action='append_const'``.  These actions add the ``const`` value to one of the attributes of the object returned by :meth:`parse_args`.  See the action_ description for examples.

-

-* When :meth:`add_argument` is called with option strings (like ``-f`` or ``--foo``) and ``nargs='?'``. This creates an optional argument that can be followed by zero or one command-line args.  When parsing the command-line, if the option string is encountered with no command-line arg following it, the value of ``const`` will be assumed instead. See the nargs_ description for examples.

-

-The ``const`` keyword argument defaults to ``None``.

-

-

-default

--------

-

-All optional arguments and some positional arguments may be omitted at the command-line.  The ``default`` keyword argument of :meth:`add_argument`, whose value defaults to ``None``, specifies what value should be used if the command-line arg is not present.  For optional arguments, the ``default`` value is used when the option string was not present at the command line::

-

-  >>> parser = argparse.ArgumentParser()

-  >>> parser.add_argument('--foo', default=42)

-  >>> parser.parse_args('--foo 2'.split())

-  Namespace(foo='2')

-  >>> parser.parse_args(''.split())

-  Namespace(foo=42)

-

-For positional arguments with nargs_ ``='?'`` or ``'*'``, the ``default`` value is used when no command-line arg was present::

-

-  >>> parser = argparse.ArgumentParser()

-  >>> parser.add_argument('foo', nargs='?', default=42)

-  >>> parser.parse_args('a'.split())

-  Namespace(foo='a')

-  >>> parser.parse_args(''.split())

-  Namespace(foo=42)

-

-

-If you don't want to see an attribute when an option was not present at the command line, you can supply ``default=argparse.SUPPRESS``::

-

-  >>> parser = argparse.ArgumentParser()

-  >>> parser.add_argument('--foo', default=argparse.SUPPRESS)

-  >>> parser.parse_args([])

-  Namespace()

-  >>> parser.parse_args(['--foo', '1'])

-  Namespace(foo='1')

-

-

-type

-----

-

-By default, ArgumentParser objects read command-line args in as simple strings. However, quite often the command-line string should instead be interpreted as another type, e.g. ``float``, ``int`` or ``file``. The ``type`` keyword argument of :meth:`add_argument` allows any necessary type-checking and type-conversions to be performed.  Many common builtin types can be used directly as the value of the ``type`` argument::

-

-  >>> parser = argparse.ArgumentParser()

-  >>> parser.add_argument('foo', type=int)

-  >>> parser.add_argument('bar', type=file)

-  >>> parser.parse_args('2 temp.txt'.split())

-  Namespace(bar=<open file 'temp.txt', mode 'r' at 0x...>, foo=2)

-

-To ease the use of various types of files, the argparse module provides the factory FileType which takes the ``mode=`` and ``bufsize=`` arguments of the ``file`` object. For example, ``FileType('w')`` can be used to create a writable file::

-

-  >>> parser = argparse.ArgumentParser()

-  >>> parser.add_argument('bar', type=argparse.FileType('w'))

-  >>> parser.parse_args(['out.txt'])

-  Namespace(bar=<open file 'out.txt', mode 'w' at 0x...>)

-

-If you need to do some special type-checking or type-conversions, you can provide your own types by passing to ``type=`` a callable that takes a single string argument and returns the type-converted value::

-

-  >>> def perfect_square(string):

-  ...     value = int(string)

-  ...     sqrt = math.sqrt(value)

-  ...     if sqrt != int(sqrt):

-  ...     raise TypeError()

-  ...     return value

-  ...    

-  >>> parser = argparse.ArgumentParser(prog='PROG')

-  >>> parser.add_argument('foo', type=perfect_square)

-  >>> parser.parse_args('9'.split())

-  Namespace(foo=9)

-  >>> parser.parse_args('7'.split())

-  usage: PROG [-h] foo

-  PROG: error: argument foo: invalid perfect_square value: '7'

-

-Note that if your type-checking function is just checking for a particular set of values, it may be more convenient to use the choices_ keyword argument::

-

-  >>> parser = argparse.ArgumentParser(prog='PROG')

-  >>> parser.add_argument('foo', type=int, choices=xrange(5, 10))

-  >>> parser.parse_args('7'.split())

-  Namespace(foo=7)

-  >>> parser.parse_args('11'.split())

-  usage: PROG [-h] {5,6,7,8,9}

-  PROG: error: argument foo: invalid choice: 11 (choose from 5, 6, 7, 8, 9)

-

-See the choices_ section for more details.

-

-

-choices

--------

-

-Some command-line args should be selected from a restricted set of values. ArgumentParser objects can be told about such sets of values by passing a container object as the ``choices`` keyword argument to :meth:`add_argument`. When the command-line is parsed with :meth:`parse_args`, arg values will be checked, and an error message will be displayed if the arg was not one of the acceptable values::

-

-  >>> parser = argparse.ArgumentParser(prog='PROG')

-  >>> parser.add_argument('foo', choices='abc')

-  >>> parser.parse_args('c'.split())

-  Namespace(foo='c')

-  >>> parser.parse_args('X'.split())

-  usage: PROG [-h] {a,b,c}

-  PROG: error: argument foo: invalid choice: 'X' (choose from 'a', 'b', 'c')

-

-Note that inclusion in the ``choices`` container is checked after any type_ conversions have been performed, so the type of the objects in the ``choices`` container should match the type_ specified::

-

-  >>> parser = argparse.ArgumentParser(prog='PROG')

-  >>> parser.add_argument('foo', type=complex, choices=[1, 1j])

-  >>> parser.parse_args('1j'.split())

-  Namespace(foo=1j)

-  >>> parser.parse_args('-- -4'.split())

-  usage: PROG [-h] {1,1j}

-  PROG: error: argument foo: invalid choice: (-4+0j) (choose from 1, 1j)

-

-Any object that supports the ``in`` operator can be passed as the ``choices`` value, so ``dict`` objects, ``set`` objects, custom containers, etc. are all supported.

-

-

-required

---------

-

-In general, the argparse module assumes that flags like ``-f`` and ``--bar`` indicate *optional* arguments, which can always be omitted at the command-line. To change this behavior, i.e. to make an option *required*, the value ``True`` should be specified for the ``required=`` keyword argument to :meth:`add_argument`::

-

-  >>> parser = argparse.ArgumentParser()

-  >>> parser.add_argument('--foo', required=True)

-  >>> parser.parse_args(['--foo', 'BAR'])

-  Namespace(foo='BAR')

-  >>> parser.parse_args([])

-  usage: argparse.py [-h] [--foo FOO]

-  argparse.py: error: option --foo is required

-

-As the example shows, if an option is marked as ``required``, :meth:`parse_args` will report an error if that option is not present at the command line.

-

-**Warning:** Required options are generally considered bad form - normal users expect *options* to be *optional*. You should avoid the use of required options whenever possible.

-

-

-help

-----

-

-A great command-line interface isn't worth anything if your users can't figure out which option does what.  So for the end-users, ``help`` is probably the most important argument to include in your :meth:`add_argument` calls.  The ``help`` value should be a string containing a brief description of what the argument specifies.  When a user requests help (usually by using ``-h`` or ``--help`` at the command-line), these ``help`` descriptions will be displayed with each argument::

-

-  >>> parser = argparse.ArgumentParser(prog='frobble')

-  >>> parser.add_argument('--foo', action='store_true',

-  ...         help='foo the bars before frobbling')

-  >>> parser.add_argument('bar', nargs='+',

-  ...         help='one of the bars to be frobbled')

-  >>> parser.parse_args('-h'.split())

-  usage: frobble [-h] [--foo] bar [bar ...]

-  

-  positional arguments:

-    bar     one of the bars to be frobbled

-  

-  optional arguments:

-    -h, --help  show this help message and exit

-    --foo   foo the bars before frobbling

-

-The ``help`` strings can include various format specifiers to avoid repetition of things like the program name or the argument default_.  The available specifiers include the program name, ``%(prog)s`` and most keyword arguments to :meth:`add_argument`, e.g. ``%(default)s``, ``%(type)s``, etc.::

-

-  >>> parser = argparse.ArgumentParser(prog='frobble')

-  >>> parser.add_argument('bar', nargs='?', type=int, default=42,

-  ...         help='the bar to %(prog)s (default: %(default)s)')

-  >>> parser.print_help()

-  usage: frobble [-h] [bar]

-  

-  positional arguments:

-    bar     the bar to frobble (default: 42)

-  

-  optional arguments:

-    -h, --help  show this help message and exit

-

-

-metavar

--------

-

-When ArgumentParser objects generate help messages, they need some way to refer to each expected argument. By default, ArgumentParser objects use the dest_ value as the "name" of each object.  By default, for positional argument actions, the dest_ value is used directly, and for optional argument actions, the dest_ value is uppercased.  So if we have a single positional argument with ``dest='bar'``, that argument will be referred to as ``bar``.  And if we have a single optional argument ``--foo`` that should be followed by a single command-line arg, that arg will be referred to as ``FOO``.  You can see this behavior in the example below::

-

-  >>> parser = argparse.ArgumentParser()

-  >>> parser.add_argument('--foo')

-  >>> parser.add_argument('bar')

-  >>> parser.parse_args('X --foo Y'.split())

-  Namespace(bar='X', foo='Y')

-  >>> parser.print_help()

-  usage:  [-h] [--foo FOO] bar

-  

-  positional arguments:

-    bar

-  

-  optional arguments:

-    -h, --help  show this help message and exit

-    --foo FOO

-

-If you would like to provide a different name for your argument in help messages, you can supply a value for the ``metavar`` keyword argument to :meth:`add_argument`::

-

-  >>> parser = argparse.ArgumentParser()

-  >>> parser.add_argument('--foo', metavar='YYY')

-  >>> parser.add_argument('bar', metavar='XXX')

-  >>> parser.parse_args('X --foo Y'.split())

-  Namespace(bar='X', foo='Y')

-  >>> parser.print_help()

-  usage:  [-h] [--foo YYY] XXX

-  

-  positional arguments:

-    XXX

-  

-  optional arguments:

-    -h, --help  show this help message and exit

-    --foo YYY

-

-Note that ``metavar`` only changes the *displayed* name - the name of the attribute on the :meth:`parse_args` object is still determined by the dest_ value.

-

-Different values of ``nargs`` may cause the metavar to be used multiple times.

-If you'd like to specify a different display name for each of the arguments, you can provide a tuple to ``metavar``::

-

-  >>> parser = argparse.ArgumentParser(prog='PROG')

-  >>> parser.add_argument('-x', nargs=2)

-  >>> parser.add_argument('--foo', nargs=2, metavar=('bar', 'baz'))

-  >>> parser.print_help()

-  usage: PROG [-h] [-x X X] [--foo bar baz]

-

-  optional arguments:

-    -h, --help     show this help message and exit

-    -x X X

-    --foo bar baz

-

-

-dest

-----

-

-Most ArgumentParser actions add some value as an attribute of the object returned by :meth:`parse_args`. The name of this attribute is determined by the ``dest`` keyword argument of :meth:`add_argument`. For positional argument actions, ``dest`` is normally supplied as the first argument to :meth:`add_argument`::

-

-  >>> parser = argparse.ArgumentParser()

-  >>> parser.add_argument('bar')

-  >>> parser.parse_args('XXX'.split())

-  Namespace(bar='XXX')

-

-For optional argument actions, the value of ``dest`` is normally inferred from the option strings. ArgumentParser objects generate the value of ``dest`` by taking the first long option string and stripping away the initial ``'--'`` string.  If no long option strings were supplied, ``dest`` will be derived from the first short option string by stripping the initial ``'-'`` character.  Any internal ``'-'`` characters will be converted to ``'_'`` characters to make sure the string is a valid attribute name. The examples below illustrate this behavior::

-

-  >>> parser = argparse.ArgumentParser()

-  >>> parser.add_argument('-f', '--foo-bar', '--foo')

-  >>> parser.add_argument('-x', '-y')

-  >>> parser.parse_args('-f 1 -x 2'.split())

-  Namespace(foo_bar='1', x='2')

-  >>> parser.parse_args('--foo 1 -y 2'.split())

-  Namespace(foo_bar='1', x='2')

-

-If you would like to use a different attribute name from the one automatically inferred by the ArgumentParser, you can supply it with an explicit ``dest`` parameter::

-

-  >>> parser = argparse.ArgumentParser()

-  >>> parser.add_argument('--foo', dest='bar')

-  >>> parser.parse_args('--foo XXX'.split())

-  Namespace(bar='XXX')

+The add_argument() method
+=========================
+
+.. method:: add_argument(name or flags..., [action], [nargs], [const], [default], [type], [choices], [required], [help], [metavar], [dest])
+
+   Define how a single command line argument should be parsed. Each parameter has its own more detailed description below, but in short they are:
+   
+   * `name or flags`_ - Either a name or a list of option strings, e.g. ``foo`` or ``-f, --foo``
+   * action_ - The basic type of action to be taken when this argument is encountered at the command-line.
+   * nargs_ - The number of command-line arguments that should be consumed.
+   * const_ - A constant value required by some action_ and nargs_ selections.
+   * default_ - The value produced if the argument is absent from the command-line.
+   * type_ - The type to which the command-line arg should be converted.
+   * choices_ - A container of the allowable values for the argument.
+   * required_ - Whether or not the command-line option may be omitted (optionals only).
+   * help_ - A brief description of what the argument does.
+   * metavar_ - A name for the argument in usage messages.
+   * dest_ - The name of the attribute to be added to the object returned by :meth:`parse_args`.
+   
+   The following sections describe how each of these are used.
+
+name or flags
+-------------
+
+The :meth:`add_argument` method needs to know whether you're expecting an optional argument, e.g. ``-f`` or ``--foo``, or a positional argument, e.g. a list of filenames. The first arguments passed to :meth:`add_argument` must therefore be either a series of flags, or a simple argument name. For example, an optional argument could be created like::
+
+  >>> parser.add_argument('-f', '--foo')
+
+while a positional argument could be created like::
+
+  >>> parser.add_argument('bar')
+
+When :meth:`parse_args` is called, optional arguments will be identified by the ``-`` prefix, and the remaining arguments will be assumed to be positional::
+
+  >>> parser = argparse.ArgumentParser(prog='PROG')
+  >>> parser.add_argument('-f', '--foo')
+  >>> parser.add_argument('bar')
+  >>> parser.parse_args(['BAR'])
+  Namespace(bar='BAR', foo=None)
+  >>> parser.parse_args(['BAR', '--foo', 'FOO'])
+  Namespace(bar='BAR', foo='FOO')
+  >>> parser.parse_args(['--foo', 'FOO'])
+  usage: PROG [-h] [-f FOO] bar
+  PROG: error: too few arguments
+
+action
+------
+
+:class:`ArgumentParser` objects associate command-line args with actions.  These actions can do just about anything with the command-line args associated with them, though most actions simply add an attribute to the object returned by :meth:`parse_args`.  When you specify a new argument using the :meth:`add_argument` method, you can indicate how the command-line args should be handled by specifying the ``action`` keyword argument. The supported actions are:
+
+* ``'store'`` - This just stores the argument's value. This is the default action. For example::
+
+    >>> parser = argparse.ArgumentParser()
+    >>> parser.add_argument('--foo')
+    >>> parser.parse_args('--foo 1'.split())
+    Namespace(foo='1')
+
+* ``'store_const'`` - This stores the value specified by the const_ keyword argument. Note that the const_ keyword argument defaults to ``None``, so you'll almost always need to provide a value for it. The ``'store_const'`` action is most commonly used with optional arguments that specify some sort of flag.  For example::
+
+    >>> parser = argparse.ArgumentParser()
+    >>> parser.add_argument('--foo', action='store_const', const=42)
+    >>> parser.parse_args('--foo'.split())
+    Namespace(foo=42)
+
+* ``'store_true'`` and ``'store_false'`` - These store the values ``True`` and ``False`` respectively.  These are basically special cases of ``'store_const'``.  For example::
+
+    >>> parser = argparse.ArgumentParser()
+    >>> parser.add_argument('--foo', action='store_true')
+    >>> parser.add_argument('--bar', action='store_false')
+    >>> parser.parse_args('--foo --bar'.split())
+    Namespace(bar=False, foo=True)
+
+* ``'append'`` - This stores a list, and appends each argument value to the list.  This is useful when you want to allow an option to be specified multiple times.  Example usage::
+
+    >>> parser = argparse.ArgumentParser()
+    >>> parser.add_argument('--foo', action='append')
+    >>> parser.parse_args('--foo 1 --foo 2'.split())
+    Namespace(foo=['1', '2'])
+
+* ``'append_const'`` - This stores a list, and appends the value specified by the const_ keyword argument to the list.  Note that the const_ keyword argument defaults to ``None``, so you'll almost always need to provide a value for it.  The ``'append_const'`` action is typically useful when you want multiple arguments to store constants to the same list, for example::
+
+    >>> parser = argparse.ArgumentParser()
+    >>> parser.add_argument('--str', dest='types', action='append_const', const=str)
+    >>> parser.add_argument('--int', dest='types', action='append_const', const=int)
+    >>> parser.parse_args('--str --int'.split())
+    Namespace(types=[<type 'str'>, <type 'int'>])
+
+You can also specify an arbitrary action by passing an object that implements the Action API.  The easiest way to do this is to extend ``argparse.Action``, supplying an appropriate ``__call__`` method.  The ``__call__`` method accepts four parameters:
+
+* ``parser`` - The ArgumentParser object which contains this action.
+* ``namespace`` - The namespace object that will be returned by :meth:`parse_args`. Most actions add an attribute to this object.
+* ``values`` - The associated command-line args, with any type-conversions applied.  (Type-conversions are specified with the type_ keyword argument to :meth:`add_argument`.
+* ``option_string`` - The option string that was used to invoke this action. The ``option_string`` argument is optional, and will be absent if the action is associated with a positional argument.
+
+So for example::
+
+  >>> class FooAction(argparse.Action):
+  ...     def __call__(self, parser, namespace, values, option_string=None):
+  ...     print '%r %r %r' % (namespace, values, option_string)
+  ...     setattr(namespace, self.dest, values)
+  ...     
+  >>> parser = argparse.ArgumentParser()
+  >>> parser.add_argument('--foo', action=FooAction)
+  >>> parser.add_argument('bar', action=FooAction)
+  >>> args = parser.parse_args('1 --foo 2'.split())
+  Namespace(bar=None, foo=None) '1' None
+  Namespace(bar='1', foo=None) '2' '--foo'
+  >>> args
+  Namespace(bar='1', foo='2')
+
+
+nargs
+-----
+
+ArgumentParser objects usually associate a single command-line argument with a single action to be taken.  In the situations where you'd like to associate a different number of command-line arguments with a single action, you can use the ``nargs`` keyword argument to :meth:`add_argument`. The supported values are:
+
+* N (an integer). N args from the command-line will be gathered together into a list.  For example::
+
+    >>> parser = argparse.ArgumentParser()
+    >>> parser.add_argument('--foo', nargs=2)
+    >>> parser.add_argument('bar', nargs=1)
+    >>> parser.parse_args('c --foo a b'.split())
+    Namespace(bar=['c'], foo=['a', 'b'])
+
+  Note that ``nargs=1`` produces a list of one item.  This is different from the default, in which the item is produced by itself.
+
+* ``'?'``. One arg will be consumed from the command-line if possible, and produced as a single item.  If no command-line arg is present, the value from default_ will be produced.  Note that for optional arguments, there is an additional case - the option string is present but not followed by a command-line arg.  In this case the value from const_ will be produced.  Some examples to illustrate this::
+
+    >>> parser = argparse.ArgumentParser()
+    >>> parser.add_argument('--foo', nargs='?', const='c', default='d')
+    >>> parser.add_argument('bar', nargs='?', default='d')
+    >>> parser.parse_args('XX --foo YY'.split())
+    Namespace(bar='XX', foo='YY')
+    >>> parser.parse_args('XX --foo'.split())
+    Namespace(bar='XX', foo='c')
+    >>> parser.parse_args(''.split())
+    Namespace(bar='d', foo='d')
+
+  One of the more common uses of ``nargs='?'`` is to allow optional input and output files::
+
+    >>> parser = argparse.ArgumentParser()
+    >>> parser.add_argument('infile', nargs='?', type=argparse.FileType('r'), default=sys.stdin)
+    >>> parser.add_argument('outfile', nargs='?', type=argparse.FileType('w'), default=sys.stdout)
+    >>> parser.parse_args(['input.txt', 'output.txt'])
+    Namespace(infile=<open file 'input.txt', mode 'r' at 0x...>, outfile=<open file 'output.txt', mode 'w' at 0x...>)
+    >>> parser.parse_args([])
+    Namespace(infile=<open file '<stdin>', mode 'r' at 0x...>, outfile=<open file '<stdout>', mode 'w' at 0x...>)
+
+* ``'*'``. All command-line args present are gathered into a list. Note that it generally doesn't make much sense to have more than one positional argument with ``nargs='*'``, but multiple optional arguments with ``nargs='*'`` is possible.  For example::
+
+    >>> parser = argparse.ArgumentParser()
+    >>> parser.add_argument('--foo', nargs='*')
+    >>> parser.add_argument('--bar', nargs='*')
+    >>> parser.add_argument('baz', nargs='*')
+    >>> parser.parse_args('a b --foo x y --bar 1 2'.split())
+    Namespace(bar=['1', '2'], baz=['a', 'b'], foo=['x', 'y'])
+
+* ``'+'``. Just like ``'*'``, all command-line args present are gathered into a list.  Additionally, an error message will be generated if there wasn't at least one command-line arg present.  For example::
+
+    >>> parser = argparse.ArgumentParser(prog='PROG')
+    >>> parser.add_argument('foo', nargs='+')
+    >>> parser.parse_args('a b'.split())
+    Namespace(foo=['a', 'b'])
+    >>> parser.parse_args(''.split())
+    usage: PROG [-h] foo [foo ...]
+    PROG: error: too few arguments
+
+If the ``nargs`` keyword argument is not provided, the number of args consumed is determined by the action_. Generally this means a single command-line arg will be consumed and a single item (not a list) will be produced.
+
+
+const
+-----
+
+The ``const`` argument of :meth:`add_argument` is used to hold constant values that are not read from the command line but are required for the various ArgumentParser actions.  The two most common uses of it are:
+
+* When :meth:`add_argument` is called with ``action='store_const'`` or ``action='append_const'``.  These actions add the ``const`` value to one of the attributes of the object returned by :meth:`parse_args`.  See the action_ description for examples.
+
+* When :meth:`add_argument` is called with option strings (like ``-f`` or ``--foo``) and ``nargs='?'``. This creates an optional argument that can be followed by zero or one command-line args.  When parsing the command-line, if the option string is encountered with no command-line arg following it, the value of ``const`` will be assumed instead. See the nargs_ description for examples.
+
+The ``const`` keyword argument defaults to ``None``.
+
+
+default
+-------
+
+All optional arguments and some positional arguments may be omitted at the command-line.  The ``default`` keyword argument of :meth:`add_argument`, whose value defaults to ``None``, specifies what value should be used if the command-line arg is not present.  For optional arguments, the ``default`` value is used when the option string was not present at the command line::
+
+  >>> parser = argparse.ArgumentParser()
+  >>> parser.add_argument('--foo', default=42)
+  >>> parser.parse_args('--foo 2'.split())
+  Namespace(foo='2')
+  >>> parser.parse_args(''.split())
+  Namespace(foo=42)
+
+For positional arguments with nargs_ ``='?'`` or ``'*'``, the ``default`` value is used when no command-line arg was present::
+
+  >>> parser = argparse.ArgumentParser()
+  >>> parser.add_argument('foo', nargs='?', default=42)
+  >>> parser.parse_args('a'.split())
+  Namespace(foo='a')
+  >>> parser.parse_args(''.split())
+  Namespace(foo=42)
+
+
+If you don't want to see an attribute when an option was not present at the command line, you can supply ``default=argparse.SUPPRESS``::
+
+  >>> parser = argparse.ArgumentParser()
+  >>> parser.add_argument('--foo', default=argparse.SUPPRESS)
+  >>> parser.parse_args([])
+  Namespace()
+  >>> parser.parse_args(['--foo', '1'])
+  Namespace(foo='1')
+
+
+type
+----
+
+By default, ArgumentParser objects read command-line args in as simple strings. However, quite often the command-line string should instead be interpreted as another type, e.g. ``float``, ``int`` or ``file``. The ``type`` keyword argument of :meth:`add_argument` allows any necessary type-checking and type-conversions to be performed.  Many common builtin types can be used directly as the value of the ``type`` argument::
+
+  >>> parser = argparse.ArgumentParser()
+  >>> parser.add_argument('foo', type=int)
+  >>> parser.add_argument('bar', type=file)
+  >>> parser.parse_args('2 temp.txt'.split())
+  Namespace(bar=<open file 'temp.txt', mode 'r' at 0x...>, foo=2)
+
+To ease the use of various types of files, the argparse module provides the factory FileType which takes the ``mode=`` and ``bufsize=`` arguments of the ``file`` object. For example, ``FileType('w')`` can be used to create a writable file::
+
+  >>> parser = argparse.ArgumentParser()
+  >>> parser.add_argument('bar', type=argparse.FileType('w'))
+  >>> parser.parse_args(['out.txt'])
+  Namespace(bar=<open file 'out.txt', mode 'w' at 0x...>)
+
+If you need to do some special type-checking or type-conversions, you can provide your own types by passing to ``type=`` a callable that takes a single string argument and returns the type-converted value::
+
+  >>> def perfect_square(string):
+  ...     value = int(string)
+  ...     sqrt = math.sqrt(value)
+  ...     if sqrt != int(sqrt):
+  ...     raise TypeError()
+  ...     return value
+  ...    
+  >>> parser = argparse.ArgumentParser(prog='PROG')
+  >>> parser.add_argument('foo', type=perfect_square)
+  >>> parser.parse_args('9'.split())
+  Namespace(foo=9)
+  >>> parser.parse_args('7'.split())
+  usage: PROG [-h] foo
+  PROG: error: argument foo: invalid perfect_square value: '7'
+
+Note that if your type-checking function is just checking for a particular set of values, it may be more convenient to use the choices_ keyword argument::
+
+  >>> parser = argparse.ArgumentParser(prog='PROG')
+  >>> parser.add_argument('foo', type=int, choices=xrange(5, 10))
+  >>> parser.parse_args('7'.split())
+  Namespace(foo=7)
+  >>> parser.parse_args('11'.split())
+  usage: PROG [-h] {5,6,7,8,9}
+  PROG: error: argument foo: invalid choice: 11 (choose from 5, 6, 7, 8, 9)
+
+See the choices_ section for more details.
+
+
+choices
+-------
+
+Some command-line args should be selected from a restricted set of values. ArgumentParser objects can be told about such sets of values by passing a container object as the ``choices`` keyword argument to :meth:`add_argument`. When the command-line is parsed with :meth:`parse_args`, arg values will be checked, and an error message will be displayed if the arg was not one of the acceptable values::
+
+  >>> parser = argparse.ArgumentParser(prog='PROG')
+  >>> parser.add_argument('foo', choices='abc')
+  >>> parser.parse_args('c'.split())
+  Namespace(foo='c')
+  >>> parser.parse_args('X'.split())
+  usage: PROG [-h] {a,b,c}
+  PROG: error: argument foo: invalid choice: 'X' (choose from 'a', 'b', 'c')
+
+Note that inclusion in the ``choices`` container is checked after any type_ conversions have been performed, so the type of the objects in the ``choices`` container should match the type_ specified::
+
+  >>> parser = argparse.ArgumentParser(prog='PROG')
+  >>> parser.add_argument('foo', type=complex, choices=[1, 1j])
+  >>> parser.parse_args('1j'.split())
+  Namespace(foo=1j)
+  >>> parser.parse_args('-- -4'.split())
+  usage: PROG [-h] {1,1j}
+  PROG: error: argument foo: invalid choice: (-4+0j) (choose from 1, 1j)
+
+Any object that supports the ``in`` operator can be passed as the ``choices`` value, so ``dict`` objects, ``set`` objects, custom containers, etc. are all supported.
+
+
+required
+--------
+
+In general, the argparse module assumes that flags like ``-f`` and ``--bar`` indicate *optional* arguments, which can always be omitted at the command-line. To change this behavior, i.e. to make an option *required*, the value ``True`` should be specified for the ``required=`` keyword argument to :meth:`add_argument`::
+
+  >>> parser = argparse.ArgumentParser()
+  >>> parser.add_argument('--foo', required=True)
+  >>> parser.parse_args(['--foo', 'BAR'])
+  Namespace(foo='BAR')
+  >>> parser.parse_args([])
+  usage: argparse.py [-h] [--foo FOO]
+  argparse.py: error: option --foo is required
+
+As the example shows, if an option is marked as ``required``, :meth:`parse_args` will report an error if that option is not present at the command line.
+
+**Warning:** Required options are generally considered bad form - normal users expect *options* to be *optional*. You should avoid the use of required options whenever possible.
+
+
+help
+----
+
+A great command-line interface isn't worth anything if your users can't figure out which option does what.  So for the end-users, ``help`` is probably the most important argument to include in your :meth:`add_argument` calls.  The ``help`` value should be a string containing a brief description of what the argument specifies.  When a user requests help (usually by using ``-h`` or ``--help`` at the command-line), these ``help`` descriptions will be displayed with each argument::
+
+  >>> parser = argparse.ArgumentParser(prog='frobble')
+  >>> parser.add_argument('--foo', action='store_true',
+  ...         help='foo the bars before frobbling')
+  >>> parser.add_argument('bar', nargs='+',
+  ...         help='one of the bars to be frobbled')
+  >>> parser.parse_args('-h'.split())
+  usage: frobble [-h] [--foo] bar [bar ...]
+  
+  positional arguments:
+    bar     one of the bars to be frobbled
+  
+  optional arguments:
+    -h, --help  show this help message and exit
+    --foo   foo the bars before frobbling
+
+The ``help`` strings can include various format specifiers to avoid repetition of things like the program name or the argument default_.  The available specifiers include the program name, ``%(prog)s`` and most keyword arguments to :meth:`add_argument`, e.g. ``%(default)s``, ``%(type)s``, etc.::
+
+  >>> parser = argparse.ArgumentParser(prog='frobble')
+  >>> parser.add_argument('bar', nargs='?', type=int, default=42,
+  ...         help='the bar to %(prog)s (default: %(default)s)')
+  >>> parser.print_help()
+  usage: frobble [-h] [bar]
+  
+  positional arguments:
+    bar     the bar to frobble (default: 42)
+  
+  optional arguments:
+    -h, --help  show this help message and exit
+
+
+metavar
+-------
+
+When ArgumentParser objects generate help messages, they need some way to refer to each expected argument. By default, ArgumentParser objects use the dest_ value as the "name" of each object.  By default, for positional argument actions, the dest_ value is used directly, and for optional argument actions, the dest_ value is uppercased.  So if we have a single positional argument with ``dest='bar'``, that argument will be referred to as ``bar``.  And if we have a single optional argument ``--foo`` that should be followed by a single command-line arg, that arg will be referred to as ``FOO``.  You can see this behavior in the example below::
+
+  >>> parser = argparse.ArgumentParser()
+  >>> parser.add_argument('--foo')
+  >>> parser.add_argument('bar')
+  >>> parser.parse_args('X --foo Y'.split())
+  Namespace(bar='X', foo='Y')
+  >>> parser.print_help()
+  usage:  [-h] [--foo FOO] bar
+  
+  positional arguments:
+    bar
+  
+  optional arguments:
+    -h, --help  show this help message and exit
+    --foo FOO
+
+If you would like to provide a different name for your argument in help messages, you can supply a value for the ``metavar`` keyword argument to :meth:`add_argument`::
+
+  >>> parser = argparse.ArgumentParser()
+  >>> parser.add_argument('--foo', metavar='YYY')
+  >>> parser.add_argument('bar', metavar='XXX')
+  >>> parser.parse_args('X --foo Y'.split())
+  Namespace(bar='X', foo='Y')
+  >>> parser.print_help()
+  usage:  [-h] [--foo YYY] XXX
+  
+  positional arguments:
+    XXX
+  
+  optional arguments:
+    -h, --help  show this help message and exit
+    --foo YYY
+
+Note that ``metavar`` only changes the *displayed* name - the name of the attribute on the :meth:`parse_args` object is still determined by the dest_ value.
+
+Different values of ``nargs`` may cause the metavar to be used multiple times.
+If you'd like to specify a different display name for each of the arguments, you can provide a tuple to ``metavar``::
+
+  >>> parser = argparse.ArgumentParser(prog='PROG')
+  >>> parser.add_argument('-x', nargs=2)
+  >>> parser.add_argument('--foo', nargs=2, metavar=('bar', 'baz'))
+  >>> parser.print_help()
+  usage: PROG [-h] [-x X X] [--foo bar baz]
+
+  optional arguments:
+    -h, --help     show this help message and exit
+    -x X X
+    --foo bar baz
+
+
+dest
+----
+
+Most ArgumentParser actions add some value as an attribute of the object returned by :meth:`parse_args`. The name of this attribute is determined by the ``dest`` keyword argument of :meth:`add_argument`. For positional argument actions, ``dest`` is normally supplied as the first argument to :meth:`add_argument`::
+
+  >>> parser = argparse.ArgumentParser()
+  >>> parser.add_argument('bar')
+  >>> parser.parse_args('XXX'.split())
+  Namespace(bar='XXX')
+
+For optional argument actions, the value of ``dest`` is normally inferred from the option strings. ArgumentParser objects generate the value of ``dest`` by taking the first long option string and stripping away the initial ``'--'`` string.  If no long option strings were supplied, ``dest`` will be derived from the first short option string by stripping the initial ``'-'`` character.  Any internal ``'-'`` characters will be converted to ``'_'`` characters to make sure the string is a valid attribute name. The examples below illustrate this behavior::
+
+  >>> parser = argparse.ArgumentParser()
+  >>> parser.add_argument('-f', '--foo-bar', '--foo')
+  >>> parser.add_argument('-x', '-y')
+  >>> parser.parse_args('-f 1 -x 2'.split())
+  Namespace(foo_bar='1', x='2')
+  >>> parser.parse_args('--foo 1 -y 2'.split())
+  Namespace(foo_bar='1', x='2')
+
+If you would like to use a different attribute name from the one automatically inferred by the ArgumentParser, you can supply it with an explicit ``dest`` parameter::
+
+  >>> parser = argparse.ArgumentParser()
+  >>> parser.add_argument('--foo', dest='bar')
+  >>> parser.parse_args('--foo XXX'.split())
+  Namespace(bar='XXX')
diff --git a/doc/source/api-docs.rst b/doc/source/api-docs.rst
index f438244..d275a1c 100644
--- a/doc/source/api-docs.rst
+++ b/doc/source/api-docs.rst
@@ -1,11 +1,11 @@
-API documentation

------------------

-

-.. toctree::

-    :maxdepth: 2

-

-    ArgumentParser

-    add_argument

-    parse_args

-    other-methods

+API documentation
+-----------------
+
+.. toctree::
+    :maxdepth: 2
+
+    ArgumentParser
+    add_argument
+    parse_args
+    other-methods
     other-utilities
\ No newline at end of file
diff --git a/doc/source/other-methods.rst b/doc/source/other-methods.rst
index 7d9f33e..9f523eb 100644
--- a/doc/source/other-methods.rst
+++ b/doc/source/other-methods.rst
@@ -1,271 +1,271 @@
-Other methods

-=============

-

-Partial parsing

----------------

-

-.. method:: parse_known_args([args], [namespace])

-

-Sometimes a script may only parse a few of the command line arguments, passing the remaining arguments on to another script or program.

-In these cases, the :meth:`parse_known_args` method can be useful.

-It works much like :meth:`parse_args` except that it does not produce an error when extra arguments are present.

-Instead, it returns a two item tuple containing the populated namespace and the list of remaining argument strings.

-::

-

-  >>> parser = argparse.ArgumentParser()

-  >>> parser.add_argument('--foo', action='store_true')

-  >>> parser.add_argument('bar')

-  >>> parser.parse_known_args(['--foo', '--badger', 'BAR', 'spam'])

-  (Namespace(bar='BAR', foo=True), ['--badger', 'spam'])

-

-

-Printing help

--------------

-

-In most typical applications, :meth:`parse_args` will take care of formatting and printing any usage or error messages. However, should you want to format or print these on your own, several methods are available:

-

-.. method:: print_usage([file]):

-

-   Print a brief description of how the :class:`ArgumentParser` should be invoked on the command line.  If ``file`` is not present, ``sys.stderr`` is assumed.

-

-.. method:: print_help([file]):

-

-   Print a help message, including the program usage and information about the arguments registered with the :class:`ArgumentParser`. If ``file`` is not present, ``sys.stderr`` is assumed.

-   

-There are also variants of these methods that simply return a string instead of printing it:

-

-.. method:: format_usage():

-

-   Return a string containing a brief description of how the :class:`ArgumentParser` should be invoked on the command line.

-

-.. method:: format_help():

-

-   Return a string containing a help message, including the program usage and information about the arguments registered with the :class:`ArgumentParser`.

-   

-

-

-Parser defaults

----------------

-

-.. method:: set_defaults(**kwargs)

-   

-   Most of the time, the attributes of the object returned by :meth:`parse_args` will be fully determined by inspecting the command-line args and the argument actions described in your :meth:`add_argument` calls.  However, sometimes it may be useful to add some additional attributes that are determined without any inspection of the command-line.  The :meth:`set_defaults` method allows you to do this::

-   

-     >>> parser = argparse.ArgumentParser()

-     >>> parser.add_argument('foo', type=int)

-     >>> parser.set_defaults(bar=42, baz='badger')

-     >>> parser.parse_args(['736'])

-     Namespace(bar=42, baz='badger', foo=736)

-   

-   Note that parser-level defaults always override argument-level defaults. So if you set a parser-level default for a name that matches an argument, the old argument default will no longer be used::

-   

-     >>> parser = argparse.ArgumentParser()

-     >>> parser.add_argument('--foo', default='bar')

-     >>> parser.set_defaults(foo='spam')

-     >>> parser.parse_args([])

-     Namespace(foo='spam')

-   

-   Parser-level defaults can be particularly useful when you're working with multiple parsers.  See the :meth:`add_subparsers` method for an example of this type.

-

-

-Sub-commands

-------------

-

-.. method:: add_subparsers()

-

-   A lot of programs split up their functionality into a number of sub-commands, for example, the ``svn`` program can invoke sub-commands like ``svn checkout``, ``svn update``, ``svn commit``, etc.  Splitting up functionality this way can be a particularly good idea when a program performs several different functions which require different kinds of command-line arguments.  ArgumentParser objects support the creation of such sub-commands with the :meth:`add_subparsers` method.  The :meth:`add_subparsers` method is normally called with no arguments and returns an special action object.  This object has a single method, ``add_parser``, which takes a command name and any ArgumentParser constructor arguments, and returns an ArgumentParser object that can be modified as usual.

-   

-   Some example usage::

-   

-     >>> # create the top-level parser

-     >>> parser = argparse.ArgumentParser(prog='PROG')

-     >>> parser.add_argument('--foo', action='store_true', help='foo help')

-     >>> subparsers = parser.add_subparsers(help='sub-command help')

-     >>>

-     >>> # create the parser for the "a" command

-     >>> parser_a = subparsers.add_parser('a', help='a help')

-     >>> parser_a.add_argument('bar', type=int, help='bar help')

-     >>>

-     >>> # create the parser for the "b" command

-     >>> parser_b = subparsers.add_parser('b', help='b help')

-     >>> parser_b.add_argument('--baz', choices='XYZ', help='baz help')

-     >>>

-     >>> # parse some arg lists

-     >>> parser.parse_args(['a', '12'])

-     Namespace(bar=12, foo=False)

-     >>> parser.parse_args(['--foo', 'b', '--baz', 'Z'])

-     Namespace(baz='Z', foo=True)

-   

-   Note that the object returned by :meth:`parse_args` will only contain attributes for the main parser and the subparser that was selected by the command line (and not any other subparsers).  So in the example above, when the ``"a"`` command is specified, only the ``foo`` and ``bar`` attributes are present, and when the ``"b"`` command is specified, only the ``foo`` and ``baz`` attributes are present.

-   

-   Similarly, when a help message is requested from a subparser, only the help for that particular parser will be printed. The help message will not include parent parser or sibling parser messages. (You can however supply a help message for each subparser command by suppling the ``help=`` argument to ``add_parser`` as above.)

-   

-   ::

-   

-     >>> parser.parse_args(['--help'])

-     usage: PROG [-h] [--foo] {a,b} ...

-     

-     positional arguments:

-       {a,b}   sub-command help

-     a     a help

-     b     b help

-     

-     optional arguments:

-       -h, --help  show this help message and exit

-       --foo   foo help

-     

-     >>> parser.parse_args(['a', '--help'])

-     usage: PROG a [-h] bar

-     

-     positional arguments:

-       bar     bar help

-     

-     optional arguments:

-       -h, --help  show this help message and exit

-     

-     >>> parser.parse_args(['b', '--help'])

-     usage: PROG b [-h] [--baz {X,Y,Z}]

-     

-     optional arguments:

-       -h, --help     show this help message and exit

-       --baz {X,Y,Z}  baz help

-

-   The :meth:`add_subparsers` method also supports ``title`` and ``description`` keyword arguments.  When either is present, the subparser's commands will appear in their own group in the help output.  For example::

-   

-     >>> parser = argparse.ArgumentParser()

-     >>> subparsers = parser.add_subparsers(title='subcommands',

-     ...                                    description='valid subcommands',

-     ...                                    help='additional help')

-     >>> subparsers.add_parser('foo')

-     >>> subparsers.add_parser('bar')

-     >>> parser.parse_args(['-h'])

-     usage:  [-h] {foo,bar} ...

-     

-     optional arguments:

-       -h, --help  show this help message and exit

-     

-     subcommands:

-       valid subcommands

-     

-       {foo,bar}   additional help

-     

-

-   One particularly effective way of handling sub-commands is to combine the use of the :meth:`add_subparsers` method with calls to :meth:`set_defaults` so that each subparser knows which Python function it should execute.  For example::

-   

-     >>> # sub-command functions

-     >>> def foo(args):

-     ...     print args.x * args.y

-     ...

-     >>> def bar(args):

-     ...     print '((%s))' % args.z

-     ...

-     >>> # create the top-level parser

-     >>> parser = argparse.ArgumentParser()

-     >>> subparsers = parser.add_subparsers()

-     >>>

-     >>> # create the parser for the "foo" command

-     >>> parser_foo = subparsers.add_parser('foo')

-     >>> parser_foo.add_argument('-x', type=int, default=1)

-     >>> parser_foo.add_argument('y', type=float)

-     >>> parser_foo.set_defaults(func=foo)

-     >>>

-     >>> # create the parser for the "bar" command

-     >>> parser_bar = subparsers.add_parser('bar')

-     >>> parser_bar.add_argument('z')

-     >>> parser_bar.set_defaults(func=bar)

-     >>>

-     >>> # parse the args and call whatever function was selected

-     >>> args = parser.parse_args('foo 1 -x 2'.split())

-     >>> args.func(args)

-     2.0

-     >>>

-     >>> # parse the args and call whatever function was selected

-     >>> args = parser.parse_args('bar XYZYX'.split())

-     >>> args.func(args)

-     ((XYZYX))

-   

-   This way, you can let :meth:`parse_args` do all the work for you, and then just call the appropriate function after the argument parsing is complete. Associating functions with actions like this is typically the easiest way to handle the different actions for each of your subparsers. However, if you find it necessary to check the name of the subparser that was invoked, you can always provide a ``dest`` keyword argument to the :meth:`add_subparsers` call::

-   

-     >>> parser = argparse.ArgumentParser()

-     >>> subparsers = parser.add_subparsers(dest='subparser_name')

-     >>> subparser1 = subparsers.add_parser('1')

-     >>> subparser1.add_argument('-x')

-     >>> subparser2 = subparsers.add_parser('2')

-     >>> subparser2.add_argument('y')

-     >>> parser.parse_args(['2', 'frobble'])

-     Namespace(subparser_name='2', y='frobble')

-

-

-Argument groups

----------------

-

-.. method:: add_argument_group([title], [description])

-

-   By default, ArgumentParser objects group command-line arguments into "positional arguments" and "optional arguments" when displaying help messages. When there is a better conceptual grouping of arguments than this default one, appropriate groups can be created using the :meth:`add_argument_group` method::

-   

-     >>> parser = argparse.ArgumentParser(prog='PROG', add_help=False)

-     >>> group = parser.add_argument_group('group')

-     >>> group.add_argument('--foo', help='foo help')

-     >>> group.add_argument('bar', help='bar help')

-     >>> parser.print_help()

-     usage: PROG [--foo FOO] bar

-     

-     group:

-       bar    bar help

-       --foo FOO  foo help

-   

-   The :meth:`add_argument_group` method returns an argument group object which has an :meth:`add_argument` method just like a regular ArgumentParser objects. When an argument is added to the group, the parser treats it just like a normal argument, but displays the argument in a separate group for help messages. The :meth:`add_argument_group` method accepts ``title`` and ``description`` arguments which can be used to customize this display::

-   

-     >>> parser = argparse.ArgumentParser(prog='PROG', add_help=False)

-     >>> group1 = parser.add_argument_group('group1', 'group1 description')

-     >>> group1.add_argument('foo', help='foo help')

-     >>> group2 = parser.add_argument_group('group2', 'group2 description')

-     >>> group2.add_argument('--bar', help='bar help')

-     >>> parser.print_help()

-     usage: PROG [--bar BAR] foo

-     

-     group1:

-       group1 description

-     

-       foo    foo help

-     

-     group2:

-       group2 description

-     

-       --bar BAR  bar help

-   

-   Note that any arguments not in your user defined groups will end up back in the usual "positional arguments" and "optional arguments" sections.

-

-

-Mutual exclusion

-----------------

-   

-.. method:: add_mutually_exclusive_group([required=False])

-

-   Sometimes, you need to make sure that only one of a couple different options is specified on the command line. You can create groups of such mutually exclusive arguments using the :meth:`add_mutually_exclusive_group` method. When :func:`parse_args` is called, argparse will make sure that only one of the arguments in the mutually exclusive group was present on the command line::

-   

-     >>> parser = argparse.ArgumentParser(prog='PROG')

-     >>> group = parser.add_mutually_exclusive_group()

-     >>> group.add_argument('--foo', action='store_true')

-     >>> group.add_argument('--bar', action='store_false')

-     >>> parser.parse_args(['--foo'])

-     Namespace(bar=True, foo=True)

-     >>> parser.parse_args(['--bar'])

-     Namespace(bar=False, foo=False)

-     >>> parser.parse_args(['--foo', '--bar'])

-     usage: PROG [-h] [--foo | --bar]

-     PROG: error: argument --bar: not allowed with argument --foo

-   

-   The :meth:`add_mutually_exclusive_group` method also accepts a ``required`` argument, to indicate that at least one of the mutually exclusive arguments is required::

-   

-     >>> parser = argparse.ArgumentParser(prog='PROG')

-     >>> group = parser.add_mutually_exclusive_group(required=True)

-     >>> group.add_argument('--foo', action='store_true')

-     >>> group.add_argument('--bar', action='store_false')

-     >>> parser.parse_args([])

-     usage: PROG [-h] (--foo | --bar)

-     PROG: error: one of the arguments --foo --bar is required

-   

-   Note that currently mutually exclusive argument groups do not support the ``title`` and ``description`` arguments of :meth:`add_argument_group`. This may change in the future however, so you are *strongly* recommended to specify ``required`` as a keyword argument if you use it.

-

-

+Other methods
+=============
+
+Partial parsing
+---------------
+
+.. method:: parse_known_args([args], [namespace])
+
+Sometimes a script may only parse a few of the command line arguments, passing the remaining arguments on to another script or program.
+In these cases, the :meth:`parse_known_args` method can be useful.
+It works much like :meth:`parse_args` except that it does not produce an error when extra arguments are present.
+Instead, it returns a two item tuple containing the populated namespace and the list of remaining argument strings.
+::
+
+  >>> parser = argparse.ArgumentParser()
+  >>> parser.add_argument('--foo', action='store_true')
+  >>> parser.add_argument('bar')
+  >>> parser.parse_known_args(['--foo', '--badger', 'BAR', 'spam'])
+  (Namespace(bar='BAR', foo=True), ['--badger', 'spam'])
+
+
+Printing help
+-------------
+
+In most typical applications, :meth:`parse_args` will take care of formatting and printing any usage or error messages. However, should you want to format or print these on your own, several methods are available:
+
+.. method:: print_usage([file]):
+
+   Print a brief description of how the :class:`ArgumentParser` should be invoked on the command line.  If ``file`` is not present, ``sys.stderr`` is assumed.
+
+.. method:: print_help([file]):
+
+   Print a help message, including the program usage and information about the arguments registered with the :class:`ArgumentParser`. If ``file`` is not present, ``sys.stderr`` is assumed.
+   
+There are also variants of these methods that simply return a string instead of printing it:
+
+.. method:: format_usage():
+
+   Return a string containing a brief description of how the :class:`ArgumentParser` should be invoked on the command line.
+
+.. method:: format_help():
+
+   Return a string containing a help message, including the program usage and information about the arguments registered with the :class:`ArgumentParser`.
+   
+
+
+Parser defaults
+---------------
+
+.. method:: set_defaults(**kwargs)
+   
+   Most of the time, the attributes of the object returned by :meth:`parse_args` will be fully determined by inspecting the command-line args and the argument actions described in your :meth:`add_argument` calls.  However, sometimes it may be useful to add some additional attributes that are determined without any inspection of the command-line.  The :meth:`set_defaults` method allows you to do this::
+   
+     >>> parser = argparse.ArgumentParser()
+     >>> parser.add_argument('foo', type=int)
+     >>> parser.set_defaults(bar=42, baz='badger')
+     >>> parser.parse_args(['736'])
+     Namespace(bar=42, baz='badger', foo=736)
+   
+   Note that parser-level defaults always override argument-level defaults. So if you set a parser-level default for a name that matches an argument, the old argument default will no longer be used::
+   
+     >>> parser = argparse.ArgumentParser()
+     >>> parser.add_argument('--foo', default='bar')
+     >>> parser.set_defaults(foo='spam')
+     >>> parser.parse_args([])
+     Namespace(foo='spam')
+   
+   Parser-level defaults can be particularly useful when you're working with multiple parsers.  See the :meth:`add_subparsers` method for an example of this type.
+
+
+Sub-commands
+------------
+
+.. method:: add_subparsers()
+
+   A lot of programs split up their functionality into a number of sub-commands, for example, the ``svn`` program can invoke sub-commands like ``svn checkout``, ``svn update``, ``svn commit``, etc.  Splitting up functionality this way can be a particularly good idea when a program performs several different functions which require different kinds of command-line arguments.  ArgumentParser objects support the creation of such sub-commands with the :meth:`add_subparsers` method.  The :meth:`add_subparsers` method is normally called with no arguments and returns an special action object.  This object has a single method, ``add_parser``, which takes a command name and any ArgumentParser constructor arguments, and returns an ArgumentParser object that can be modified as usual.
+   
+   Some example usage::
+   
+     >>> # create the top-level parser
+     >>> parser = argparse.ArgumentParser(prog='PROG')
+     >>> parser.add_argument('--foo', action='store_true', help='foo help')
+     >>> subparsers = parser.add_subparsers(help='sub-command help')
+     >>>
+     >>> # create the parser for the "a" command
+     >>> parser_a = subparsers.add_parser('a', help='a help')
+     >>> parser_a.add_argument('bar', type=int, help='bar help')
+     >>>
+     >>> # create the parser for the "b" command
+     >>> parser_b = subparsers.add_parser('b', help='b help')
+     >>> parser_b.add_argument('--baz', choices='XYZ', help='baz help')
+     >>>
+     >>> # parse some arg lists
+     >>> parser.parse_args(['a', '12'])
+     Namespace(bar=12, foo=False)
+     >>> parser.parse_args(['--foo', 'b', '--baz', 'Z'])
+     Namespace(baz='Z', foo=True)
+   
+   Note that the object returned by :meth:`parse_args` will only contain attributes for the main parser and the subparser that was selected by the command line (and not any other subparsers).  So in the example above, when the ``"a"`` command is specified, only the ``foo`` and ``bar`` attributes are present, and when the ``"b"`` command is specified, only the ``foo`` and ``baz`` attributes are present.
+   
+   Similarly, when a help message is requested from a subparser, only the help for that particular parser will be printed. The help message will not include parent parser or sibling parser messages. (You can however supply a help message for each subparser command by suppling the ``help=`` argument to ``add_parser`` as above.)
+   
+   ::
+   
+     >>> parser.parse_args(['--help'])
+     usage: PROG [-h] [--foo] {a,b} ...
+     
+     positional arguments:
+       {a,b}   sub-command help
+     a     a help
+     b     b help
+     
+     optional arguments:
+       -h, --help  show this help message and exit
+       --foo   foo help
+     
+     >>> parser.parse_args(['a', '--help'])
+     usage: PROG a [-h] bar
+     
+     positional arguments:
+       bar     bar help
+     
+     optional arguments:
+       -h, --help  show this help message and exit
+     
+     >>> parser.parse_args(['b', '--help'])
+     usage: PROG b [-h] [--baz {X,Y,Z}]
+     
+     optional arguments:
+       -h, --help     show this help message and exit
+       --baz {X,Y,Z}  baz help
+
+   The :meth:`add_subparsers` method also supports ``title`` and ``description`` keyword arguments.  When either is present, the subparser's commands will appear in their own group in the help output.  For example::
+   
+     >>> parser = argparse.ArgumentParser()
+     >>> subparsers = parser.add_subparsers(title='subcommands',
+     ...                                    description='valid subcommands',
+     ...                                    help='additional help')
+     >>> subparsers.add_parser('foo')
+     >>> subparsers.add_parser('bar')
+     >>> parser.parse_args(['-h'])
+     usage:  [-h] {foo,bar} ...
+     
+     optional arguments:
+       -h, --help  show this help message and exit
+     
+     subcommands:
+       valid subcommands
+     
+       {foo,bar}   additional help
+     
+
+   One particularly effective way of handling sub-commands is to combine the use of the :meth:`add_subparsers` method with calls to :meth:`set_defaults` so that each subparser knows which Python function it should execute.  For example::
+   
+     >>> # sub-command functions
+     >>> def foo(args):
+     ...     print args.x * args.y
+     ...
+     >>> def bar(args):
+     ...     print '((%s))' % args.z
+     ...
+     >>> # create the top-level parser
+     >>> parser = argparse.ArgumentParser()
+     >>> subparsers = parser.add_subparsers()
+     >>>
+     >>> # create the parser for the "foo" command
+     >>> parser_foo = subparsers.add_parser('foo')
+     >>> parser_foo.add_argument('-x', type=int, default=1)
+     >>> parser_foo.add_argument('y', type=float)
+     >>> parser_foo.set_defaults(func=foo)
+     >>>
+     >>> # create the parser for the "bar" command
+     >>> parser_bar = subparsers.add_parser('bar')
+     >>> parser_bar.add_argument('z')
+     >>> parser_bar.set_defaults(func=bar)
+     >>>
+     >>> # parse the args and call whatever function was selected
+     >>> args = parser.parse_args('foo 1 -x 2'.split())
+     >>> args.func(args)
+     2.0
+     >>>
+     >>> # parse the args and call whatever function was selected
+     >>> args = parser.parse_args('bar XYZYX'.split())
+     >>> args.func(args)
+     ((XYZYX))
+   
+   This way, you can let :meth:`parse_args` do all the work for you, and then just call the appropriate function after the argument parsing is complete. Associating functions with actions like this is typically the easiest way to handle the different actions for each of your subparsers. However, if you find it necessary to check the name of the subparser that was invoked, you can always provide a ``dest`` keyword argument to the :meth:`add_subparsers` call::
+   
+     >>> parser = argparse.ArgumentParser()
+     >>> subparsers = parser.add_subparsers(dest='subparser_name')
+     >>> subparser1 = subparsers.add_parser('1')
+     >>> subparser1.add_argument('-x')
+     >>> subparser2 = subparsers.add_parser('2')
+     >>> subparser2.add_argument('y')
+     >>> parser.parse_args(['2', 'frobble'])
+     Namespace(subparser_name='2', y='frobble')
+
+
+Argument groups
+---------------
+
+.. method:: add_argument_group([title], [description])
+
+   By default, ArgumentParser objects group command-line arguments into "positional arguments" and "optional arguments" when displaying help messages. When there is a better conceptual grouping of arguments than this default one, appropriate groups can be created using the :meth:`add_argument_group` method::
+   
+     >>> parser = argparse.ArgumentParser(prog='PROG', add_help=False)
+     >>> group = parser.add_argument_group('group')
+     >>> group.add_argument('--foo', help='foo help')
+     >>> group.add_argument('bar', help='bar help')
+     >>> parser.print_help()
+     usage: PROG [--foo FOO] bar
+     
+     group:
+       bar    bar help
+       --foo FOO  foo help
+   
+   The :meth:`add_argument_group` method returns an argument group object which has an :meth:`add_argument` method just like a regular ArgumentParser objects. When an argument is added to the group, the parser treats it just like a normal argument, but displays the argument in a separate group for help messages. The :meth:`add_argument_group` method accepts ``title`` and ``description`` arguments which can be used to customize this display::
+   
+     >>> parser = argparse.ArgumentParser(prog='PROG', add_help=False)
+     >>> group1 = parser.add_argument_group('group1', 'group1 description')
+     >>> group1.add_argument('foo', help='foo help')
+     >>> group2 = parser.add_argument_group('group2', 'group2 description')
+     >>> group2.add_argument('--bar', help='bar help')
+     >>> parser.print_help()
+     usage: PROG [--bar BAR] foo
+     
+     group1:
+       group1 description
+     
+       foo    foo help
+     
+     group2:
+       group2 description
+     
+       --bar BAR  bar help
+   
+   Note that any arguments not in your user defined groups will end up back in the usual "positional arguments" and "optional arguments" sections.
+
+
+Mutual exclusion
+----------------
+   
+.. method:: add_mutually_exclusive_group([required=False])
+
+   Sometimes, you need to make sure that only one of a couple different options is specified on the command line. You can create groups of such mutually exclusive arguments using the :meth:`add_mutually_exclusive_group` method. When :func:`parse_args` is called, argparse will make sure that only one of the arguments in the mutually exclusive group was present on the command line::
+   
+     >>> parser = argparse.ArgumentParser(prog='PROG')
+     >>> group = parser.add_mutually_exclusive_group()
+     >>> group.add_argument('--foo', action='store_true')
+     >>> group.add_argument('--bar', action='store_false')
+     >>> parser.parse_args(['--foo'])
+     Namespace(bar=True, foo=True)
+     >>> parser.parse_args(['--bar'])
+     Namespace(bar=False, foo=False)
+     >>> parser.parse_args(['--foo', '--bar'])
+     usage: PROG [-h] [--foo | --bar]
+     PROG: error: argument --bar: not allowed with argument --foo
+   
+   The :meth:`add_mutually_exclusive_group` method also accepts a ``required`` argument, to indicate that at least one of the mutually exclusive arguments is required::
+   
+     >>> parser = argparse.ArgumentParser(prog='PROG')
+     >>> group = parser.add_mutually_exclusive_group(required=True)
+     >>> group.add_argument('--foo', action='store_true')
+     >>> group.add_argument('--bar', action='store_false')
+     >>> parser.parse_args([])
+     usage: PROG [-h] (--foo | --bar)
+     PROG: error: one of the arguments --foo --bar is required
+   
+   Note that currently mutually exclusive argument groups do not support the ``title`` and ``description`` arguments of :meth:`add_argument_group`. This may change in the future however, so you are *strongly* recommended to specify ``required`` as a keyword argument if you use it.
+
+
diff --git a/doc/source/other-utilities.rst b/doc/source/other-utilities.rst
index 5efc785..8712cf4 100644
--- a/doc/source/other-utilities.rst
+++ b/doc/source/other-utilities.rst
@@ -1,21 +1,21 @@
-Other utilities

-===============

-

-FileType objects

-----------------

-

-.. class:: FileType(mode='r', bufsize=None)

-

-   The :class:`FileType` factory creates objects that can be passed to the type argument of :meth:`add_argument`. Arguments that have :class:`FileType` objects as their type will open command-line args as files with the requested modes and buffer sizes:

-   

-   >>> parser = argparse.ArgumentParser()

-   >>> parser.add_argument('--output', type=argparse.FileType('wb', 0))

-   >>> parser.parse_args(['--output', 'out'])

-   Namespace(output=<open file 'out', mode 'wb' at 0x...>)

-   

-   FileType objects understand the pseudo-argument ``'-'`` and automatically convert this into ``sys.stdin`` for readable :class:`FileType` objects and ``sys.stdout`` for writable :class:`FileType` objects:

-   

-   >>> parser = argparse.ArgumentParser()

-   >>> parser.add_argument('infile', type=argparse.FileType('r'))

-   >>> parser.parse_args(['-'])

-   Namespace(infile=<open file '<stdin>', mode 'r' at 0x...>)

+Other utilities
+===============
+
+FileType objects
+----------------
+
+.. class:: FileType(mode='r', bufsize=None)
+
+   The :class:`FileType` factory creates objects that can be passed to the type argument of :meth:`add_argument`. Arguments that have :class:`FileType` objects as their type will open command-line args as files with the requested modes and buffer sizes:
+   
+   >>> parser = argparse.ArgumentParser()
+   >>> parser.add_argument('--output', type=argparse.FileType('wb', 0))
+   >>> parser.parse_args(['--output', 'out'])
+   Namespace(output=<open file 'out', mode 'wb' at 0x...>)
+   
+   FileType objects understand the pseudo-argument ``'-'`` and automatically convert this into ``sys.stdin`` for readable :class:`FileType` objects and ``sys.stdout`` for writable :class:`FileType` objects:
+   
+   >>> parser = argparse.ArgumentParser()
+   >>> parser.add_argument('infile', type=argparse.FileType('r'))
+   >>> parser.parse_args(['-'])
+   Namespace(infile=<open file '<stdin>', mode 'r' at 0x...>)
diff --git a/doc/source/overview.rst b/doc/source/overview.rst
index 5cedae2..13d0445 100644
--- a/doc/source/overview.rst
+++ b/doc/source/overview.rst
@@ -1,56 +1,56 @@
-Introduction to argparse

-========================

-

-Pretty much every script that uses the argparse module will start out by creating an :class:`ArgumentParser` object. Typically, this will look something like::

-

-  >>> parser = argparse.ArgumentParser(description='Frabble the foo and the bars')

-

-The :class:`ArgumentParser` object will hold all the information necessary to parse the command line into a more manageable form for your program.

-

-

-Adding arguments

-----------------

-

-Once you've created an :class:`ArgumentParser`, you'll want to fill it with information about your program arguments. You typically do this by making calls to the :meth:`add_argument` method.  Generally, these calls tell the :class:`ArgumentParser` how to take the strings on the command line and turn them into objects for you. This information is stored and used when :meth:`parse_args` is called. For example, if we add some arguments like this::

-

-  >>> parser.add_argument('-f', '--foo', action='store_true', help='frabble the foos')

-  >>> parser.add_argument('bar', nargs='+', type=int, help='a bar to be frabbled')

-

-when we later call :meth:`parse_args`, we can expect it to return an object with two attributes, ``foo`` and ``bar``.  The ``foo`` attribute will be ``True`` if ``--foo`` was supplied at the command-line, and the ``bar`` attribute will be a list of ints determined from the remaining command-line arguments::

-

-  >>> parser.parse_args('--foo 1 2 3 5 8'.split())

-  Namespace(bar=[1, 2, 3, 5, 8], foo=True)

-

-As you can see from the example above, calls to :meth:`add_argument` start with either a single string name for positional arguments or a series of option strings (beginning with ``'-'``) for optional arguments.  The remaining keyword arguments to :meth:`add_argument` specify exactly what sort of action should be carried out when the :class:`ArgumentParser` object encounters the corresponding command-line args.  So in our example above, we are telling the :class:`ArgumentParser` object that when it encounters ``--foo`` in the command-line args, it should invoke the ``'store_true'`` action.

-

-

-Parsing arguments

------------------

-

-Once an :class:`ArgumentParser` has been initialized with appropriate calls to :meth:`add_argument`, it can be instructed to parse the command-line args by calling the :meth:`parse_args` method.  This will inspect the command-line, convert each arg to the appropriate type and then invoke the appropriate action.  In most cases, this means a simple namespace object will be built up from attributes parsed out of the command-line.

-

-In the most common case, :meth:`parse_args` will be called with no arguments, and the :class:`ArgumentParser` will determine the command-line args from ``sys.argv``.  The following example sets up a simple :class:`ArgumentParser` and then calls :meth:`parse_args` in this manner::

-

-  import argparse

-  

-  if __name__ == '__main__':

-  parser = argparse.ArgumentParser()

-  parser.add_argument(

-      'integers', metavar='int', type=int, choices=xrange(10),

-       nargs='+', help='an integer in the range 0..9')

-  parser.add_argument(

-      '--sum', dest='accumulate', action='store_const', const=sum,

-    default=max, help='sum the integers (default: find the max)')

-  

-  args = parser.parse_args()

-  print args.accumulate(args.integers)

-

-Assuming this program is saved in the file ``script.py``, the call to :meth:`parse_args` means that we get the following behavior when running the program from the command-line::

-

-  $ script.py 1 2 3 4

-  4

-  

-  $ script.py --sum 1 2 3 4

-  10

-

-That's pretty much it. You're now ready to go write some command line interfaces!

+Introduction to argparse
+========================
+
+Pretty much every script that uses the argparse module will start out by creating an :class:`ArgumentParser` object. Typically, this will look something like::
+
+  >>> parser = argparse.ArgumentParser(description='Frabble the foo and the bars')
+
+The :class:`ArgumentParser` object will hold all the information necessary to parse the command line into a more manageable form for your program.
+
+
+Adding arguments
+----------------
+
+Once you've created an :class:`ArgumentParser`, you'll want to fill it with information about your program arguments. You typically do this by making calls to the :meth:`add_argument` method.  Generally, these calls tell the :class:`ArgumentParser` how to take the strings on the command line and turn them into objects for you. This information is stored and used when :meth:`parse_args` is called. For example, if we add some arguments like this::
+
+  >>> parser.add_argument('-f', '--foo', action='store_true', help='frabble the foos')
+  >>> parser.add_argument('bar', nargs='+', type=int, help='a bar to be frabbled')
+
+when we later call :meth:`parse_args`, we can expect it to return an object with two attributes, ``foo`` and ``bar``.  The ``foo`` attribute will be ``True`` if ``--foo`` was supplied at the command-line, and the ``bar`` attribute will be a list of ints determined from the remaining command-line arguments::
+
+  >>> parser.parse_args('--foo 1 2 3 5 8'.split())
+  Namespace(bar=[1, 2, 3, 5, 8], foo=True)
+
+As you can see from the example above, calls to :meth:`add_argument` start with either a single string name for positional arguments or a series of option strings (beginning with ``'-'``) for optional arguments.  The remaining keyword arguments to :meth:`add_argument` specify exactly what sort of action should be carried out when the :class:`ArgumentParser` object encounters the corresponding command-line args.  So in our example above, we are telling the :class:`ArgumentParser` object that when it encounters ``--foo`` in the command-line args, it should invoke the ``'store_true'`` action.
+
+
+Parsing arguments
+-----------------
+
+Once an :class:`ArgumentParser` has been initialized with appropriate calls to :meth:`add_argument`, it can be instructed to parse the command-line args by calling the :meth:`parse_args` method.  This will inspect the command-line, convert each arg to the appropriate type and then invoke the appropriate action.  In most cases, this means a simple namespace object will be built up from attributes parsed out of the command-line.
+
+In the most common case, :meth:`parse_args` will be called with no arguments, and the :class:`ArgumentParser` will determine the command-line args from ``sys.argv``.  The following example sets up a simple :class:`ArgumentParser` and then calls :meth:`parse_args` in this manner::
+
+  import argparse
+  
+  if __name__ == '__main__':
+  parser = argparse.ArgumentParser()
+  parser.add_argument(
+      'integers', metavar='int', type=int, choices=xrange(10),
+       nargs='+', help='an integer in the range 0..9')
+  parser.add_argument(
+      '--sum', dest='accumulate', action='store_const', const=sum,
+    default=max, help='sum the integers (default: find the max)')
+  
+  args = parser.parse_args()
+  print args.accumulate(args.integers)
+
+Assuming this program is saved in the file ``script.py``, the call to :meth:`parse_args` means that we get the following behavior when running the program from the command-line::
+
+  $ script.py 1 2 3 4
+  4
+  
+  $ script.py --sum 1 2 3 4
+  10
+
+That's pretty much it. You're now ready to go write some command line interfaces!
diff --git a/doc/source/parse_args.rst b/doc/source/parse_args.rst
index 9ce86f4..4e460be 100644
--- a/doc/source/parse_args.rst
+++ b/doc/source/parse_args.rst
@@ -1,161 +1,161 @@
-The parse_args() method

-=========================

-

-.. method:: parse_args([args], [namespace])

-

-   Convert the strings to objects and assign them as attributes of the namespace. Return the populated namespace.

-   

-   Previous calls to :meth:`add_argument` determine exactly what objects are created and how they are assigned. See the documentation for :meth:`add_argument` for details.

-   

-   By default, the arg strings are taken from ``sys.argv``, and a new empty ``Namespace`` object is created for the attributes.

-

-Option value syntax

--------------------

-

-The :meth:`parse_args` method supports several ways of specifying the value of an option (if it takes one). In the simplest case, the option and its value are passed as two separate arguments::

-

-  >>> parser = argparse.ArgumentParser(prog='PROG')

-  >>> parser.add_argument('-x')

-  >>> parser.add_argument('--foo')

-  >>> parser.parse_args('-x X'.split())

-  Namespace(foo=None, x='X')

-  >>> parser.parse_args('--foo FOO'.split())

-  Namespace(foo='FOO', x=None)

-

-For long options (options with names longer than a single character), you may also pass the option and value as a single command line argument, using ``=`` to separate them::

-

-  >>> parser.parse_args('--foo=FOO'.split())

-  Namespace(foo='FOO', x=None)

-

-For short options (options only one character long), you may simply concatenate the option and its value::

-

-  >>> parser.parse_args('-xX'.split())

-  Namespace(foo=None, x='X')

-

-You can also combine several short options together, using only a single ``-`` prefix, as long as only the last option (or none of them) requires a value::

-

-  >>> parser = argparse.ArgumentParser(prog='PROG')

-  >>> parser.add_argument('-x', action='store_true')

-  >>> parser.add_argument('-y', action='store_true')

-  >>> parser.add_argument('-z')

-  >>> parser.parse_args('-xyzZ'.split())

-  Namespace(x=True, y=True, z='Z')

-

-

-Invalid arguments

------------------

-

-While parsing the command-line, ``parse_args`` checks for a variety of errors, including ambiguous options, invalid types, invalid options, wrong number of positional arguments, etc. When it encounters such an error, it exits and prints the error along with a usage message::

-

-  >>> parser = argparse.ArgumentParser(prog='PROG')

-  >>> parser.add_argument('--foo', type=int)

-  >>> parser.add_argument('bar', nargs='?')

-  

-  >>> # invalid type

-  >>> parser.parse_args(['--foo', 'spam'])

-  usage: PROG [-h] [--foo FOO] [bar]

-  PROG: error: argument --foo: invalid int value: 'spam'

-  

-  >>> # invalid option

-  >>> parser.parse_args(['--bar'])

-  usage: PROG [-h] [--foo FOO] [bar]

-  PROG: error: no such option: --bar

-  

-  >>> # wrong number of arguments

-  >>> parser.parse_args(['spam', 'badger'])

-  usage: PROG [-h] [--foo FOO] [bar]

-  PROG: error: extra arguments found: badger

-

-

-Arguments containing ``"-"``

-----------------------------

-

-The ``parse_args`` method attempts to give errors whenever the user has clearly made a mistake, but some situations are inherently ambiguous. For example, the command-line arg ``'-1'`` could either be an attempt to specify an option or an attempt to provide a positional argument. The ``parse_args`` method is cautious here: positional arguments may only begin with ``'-'`` if they look like negative numbers and there are no options in the parser that look like negative numbers::

-

-  >>> parser = argparse.ArgumentParser(prog='PROG')

-  >>> parser.add_argument('-x')

-  >>> parser.add_argument('foo', nargs='?')

-  

-  >>> # no negative number options, so -1 is a positional argument

-  >>> parser.parse_args(['-x', '-1'])

-  Namespace(foo=None, x='-1')

-  

-  >>> # no negative number options, so -1 and -5 are positional arguments

-  >>> parser.parse_args(['-x', '-1', '-5'])

-  Namespace(foo='-5', x='-1')

-  

-  >>> parser = argparse.ArgumentParser(prog='PROG')

-  >>> parser.add_argument('-1', dest='one')

-  >>> parser.add_argument('foo', nargs='?')

-  

-  >>> # negative number options present, so -1 is an option

-  >>> parser.parse_args(['-1', 'X'])

-  Namespace(foo=None, one='X')

-  

-  >>> # negative number options present, so -2 is an option

-  >>> parser.parse_args(['-2'])

-  usage: PROG [-h] [-1 ONE] [foo]

-  PROG: error: no such option: -2

-  

-  >>> # negative number options present, so both -1s are options

-  >>> parser.parse_args(['-1', '-1'])

-  usage: PROG [-h] [-1 ONE] [foo]

-  PROG: error: argument -1: expected one argument

-

-If you have positional arguments that must begin with ``'-'`` and don't look like negative numbers, you can insert the pseudo-argument ``'--'`` which tells ``parse_args`` that everything after that is a positional argument::

-

-  >>> parser.parse_args(['--', '-f'])

-  Namespace(foo='-f', one=None)

-

-

-Argument abbreviations

-----------------------

-

-The :meth:`parse_args` method allows you to abbreviate long options if the abbreviation is unambiguous::

-

-  >>> parser = argparse.ArgumentParser(prog='PROG')

-  >>> parser.add_argument('-bacon')

-  >>> parser.add_argument('-badger')

-  >>> parser.parse_args('-bac MMM'.split())

-  Namespace(bacon='MMM', badger=None)

-  >>> parser.parse_args('-bad WOOD'.split())

-  Namespace(bacon=None, badger='WOOD')

-  >>> parser.parse_args('-ba BA'.split())

-  usage: PROG [-h] [-bacon BACON] [-badger BADGER]

-  PROG: error: ambiguous option: -ba could match -badger, -bacon

-

-As you can see above, you will get an error if you pick a prefix that could refer to more than one option.

-

-

-Beyond ``sys.argv``

--------------------

-

-Sometimes it may be useful to have an ArgumentParser parse args other than those of ``sys.argv``.  This can be accomplished by passing a list of strings to ``parse_args``.  You may have noticed that the examples in the argparse documentation have made heavy use of this calling style - it is much easier to use at the interactive prompt::

-

-  >>> parser = argparse.ArgumentParser()

-  >>> parser.add_argument(

-  ...     'integers', metavar='int', type=int, choices=xrange(10),

-  ...  nargs='+', help='an integer in the range 0..9')

-  >>> parser.add_argument(

-  ...     '--sum', dest='accumulate', action='store_const', const=sum,

-  ...   default=max, help='sum the integers (default: find the max)')

-  >>> parser.parse_args(['1', '2', '3', '4'])

-  Namespace(accumulate=<built-in function max>, integers=[1, 2, 3, 4])

-  >>> parser.parse_args('1 2 3 4 --sum'.split())

-  Namespace(accumulate=<built-in function sum>, integers=[1, 2, 3, 4])

-

-

-Custom namespaces

------------------

-

-It may also be useful to have an ArgumentParser assign attributes to an already existing object, rather than the newly-created Namespace object that is normally used. This can be achieved by specifying the ``namespace=`` keyword argument::

-

-  >>> class C(object):

-  ...     pass

-  ...    

-  >>> c = C()

-  >>> parser = argparse.ArgumentParser()

-  >>> parser.add_argument('--foo')

-  >>> parser.parse_args(args=['--foo', 'BAR'], namespace=c)

-  >>> c.foo

-  'BAR'

+The parse_args() method
+=========================
+
+.. method:: parse_args([args], [namespace])
+
+   Convert the strings to objects and assign them as attributes of the namespace. Return the populated namespace.
+   
+   Previous calls to :meth:`add_argument` determine exactly what objects are created and how they are assigned. See the documentation for :meth:`add_argument` for details.
+   
+   By default, the arg strings are taken from ``sys.argv``, and a new empty ``Namespace`` object is created for the attributes.
+
+Option value syntax
+-------------------
+
+The :meth:`parse_args` method supports several ways of specifying the value of an option (if it takes one). In the simplest case, the option and its value are passed as two separate arguments::
+
+  >>> parser = argparse.ArgumentParser(prog='PROG')
+  >>> parser.add_argument('-x')
+  >>> parser.add_argument('--foo')
+  >>> parser.parse_args('-x X'.split())
+  Namespace(foo=None, x='X')
+  >>> parser.parse_args('--foo FOO'.split())
+  Namespace(foo='FOO', x=None)
+
+For long options (options with names longer than a single character), you may also pass the option and value as a single command line argument, using ``=`` to separate them::
+
+  >>> parser.parse_args('--foo=FOO'.split())
+  Namespace(foo='FOO', x=None)
+
+For short options (options only one character long), you may simply concatenate the option and its value::
+
+  >>> parser.parse_args('-xX'.split())
+  Namespace(foo=None, x='X')
+
+You can also combine several short options together, using only a single ``-`` prefix, as long as only the last option (or none of them) requires a value::
+
+  >>> parser = argparse.ArgumentParser(prog='PROG')
+  >>> parser.add_argument('-x', action='store_true')
+  >>> parser.add_argument('-y', action='store_true')
+  >>> parser.add_argument('-z')
+  >>> parser.parse_args('-xyzZ'.split())
+  Namespace(x=True, y=True, z='Z')
+
+
+Invalid arguments
+-----------------
+
+While parsing the command-line, ``parse_args`` checks for a variety of errors, including ambiguous options, invalid types, invalid options, wrong number of positional arguments, etc. When it encounters such an error, it exits and prints the error along with a usage message::
+
+  >>> parser = argparse.ArgumentParser(prog='PROG')
+  >>> parser.add_argument('--foo', type=int)
+  >>> parser.add_argument('bar', nargs='?')
+  
+  >>> # invalid type
+  >>> parser.parse_args(['--foo', 'spam'])
+  usage: PROG [-h] [--foo FOO] [bar]
+  PROG: error: argument --foo: invalid int value: 'spam'
+  
+  >>> # invalid option
+  >>> parser.parse_args(['--bar'])
+  usage: PROG [-h] [--foo FOO] [bar]
+  PROG: error: no such option: --bar
+  
+  >>> # wrong number of arguments
+  >>> parser.parse_args(['spam', 'badger'])
+  usage: PROG [-h] [--foo FOO] [bar]
+  PROG: error: extra arguments found: badger
+
+
+Arguments containing ``"-"``
+----------------------------
+
+The ``parse_args`` method attempts to give errors whenever the user has clearly made a mistake, but some situations are inherently ambiguous. For example, the command-line arg ``'-1'`` could either be an attempt to specify an option or an attempt to provide a positional argument. The ``parse_args`` method is cautious here: positional arguments may only begin with ``'-'`` if they look like negative numbers and there are no options in the parser that look like negative numbers::
+
+  >>> parser = argparse.ArgumentParser(prog='PROG')
+  >>> parser.add_argument('-x')
+  >>> parser.add_argument('foo', nargs='?')
+  
+  >>> # no negative number options, so -1 is a positional argument
+  >>> parser.parse_args(['-x', '-1'])
+  Namespace(foo=None, x='-1')
+  
+  >>> # no negative number options, so -1 and -5 are positional arguments
+  >>> parser.parse_args(['-x', '-1', '-5'])
+  Namespace(foo='-5', x='-1')
+  
+  >>> parser = argparse.ArgumentParser(prog='PROG')
+  >>> parser.add_argument('-1', dest='one')
+  >>> parser.add_argument('foo', nargs='?')
+  
+  >>> # negative number options present, so -1 is an option
+  >>> parser.parse_args(['-1', 'X'])
+  Namespace(foo=None, one='X')
+  
+  >>> # negative number options present, so -2 is an option
+  >>> parser.parse_args(['-2'])
+  usage: PROG [-h] [-1 ONE] [foo]
+  PROG: error: no such option: -2
+  
+  >>> # negative number options present, so both -1s are options
+  >>> parser.parse_args(['-1', '-1'])
+  usage: PROG [-h] [-1 ONE] [foo]
+  PROG: error: argument -1: expected one argument
+
+If you have positional arguments that must begin with ``'-'`` and don't look like negative numbers, you can insert the pseudo-argument ``'--'`` which tells ``parse_args`` that everything after that is a positional argument::
+
+  >>> parser.parse_args(['--', '-f'])
+  Namespace(foo='-f', one=None)
+
+
+Argument abbreviations
+----------------------
+
+The :meth:`parse_args` method allows you to abbreviate long options if the abbreviation is unambiguous::
+
+  >>> parser = argparse.ArgumentParser(prog='PROG')
+  >>> parser.add_argument('-bacon')
+  >>> parser.add_argument('-badger')
+  >>> parser.parse_args('-bac MMM'.split())
+  Namespace(bacon='MMM', badger=None)
+  >>> parser.parse_args('-bad WOOD'.split())
+  Namespace(bacon=None, badger='WOOD')
+  >>> parser.parse_args('-ba BA'.split())
+  usage: PROG [-h] [-bacon BACON] [-badger BADGER]
+  PROG: error: ambiguous option: -ba could match -badger, -bacon
+
+As you can see above, you will get an error if you pick a prefix that could refer to more than one option.
+
+
+Beyond ``sys.argv``
+-------------------
+
+Sometimes it may be useful to have an ArgumentParser parse args other than those of ``sys.argv``.  This can be accomplished by passing a list of strings to ``parse_args``.  You may have noticed that the examples in the argparse documentation have made heavy use of this calling style - it is much easier to use at the interactive prompt::
+
+  >>> parser = argparse.ArgumentParser()
+  >>> parser.add_argument(
+  ...     'integers', metavar='int', type=int, choices=xrange(10),
+  ...  nargs='+', help='an integer in the range 0..9')
+  >>> parser.add_argument(
+  ...     '--sum', dest='accumulate', action='store_const', const=sum,
+  ...   default=max, help='sum the integers (default: find the max)')
+  >>> parser.parse_args(['1', '2', '3', '4'])
+  Namespace(accumulate=<built-in function max>, integers=[1, 2, 3, 4])
+  >>> parser.parse_args('1 2 3 4 --sum'.split())
+  Namespace(accumulate=<built-in function sum>, integers=[1, 2, 3, 4])
+
+
+Custom namespaces
+-----------------
+
+It may also be useful to have an ArgumentParser assign attributes to an already existing object, rather than the newly-created Namespace object that is normally used. This can be achieved by specifying the ``namespace=`` keyword argument::
+
+  >>> class C(object):
+  ...     pass
+  ...    
+  >>> c = C()
+  >>> parser = argparse.ArgumentParser()
+  >>> parser.add_argument('--foo')
+  >>> parser.parse_args(args=['--foo', 'BAR'], namespace=c)
+  >>> c.foo
+  'BAR'