Branch merge

1 files changed, 57 insertions, 53 deletions

diff --git a/Doc/library/argparse.rst b/Doc/library/argparse.rst
index 08231411..bf0899d 100644
--- a/Doc/library/argparse.rst
+++ b/Doc/library/argparse.rst
@@ -2,11 +2,15 @@
 ===============================================================================
 
 .. module:: argparse
-   :synopsis: Command-line option and argument-parsing library.
+   :synopsis: Command-line option and argument parsing library.
 .. moduleauthor:: Steven Bethard <steven.bethard@gmail.com>
-.. versionadded:: 2.7
 .. sectionauthor:: Steven Bethard <steven.bethard@gmail.com>
 
+.. versionadded:: 2.7
+
+**Source code:** :source:`Lib/argparse.py`
+
+--------------
 
 The :mod:`argparse` module makes it easy to write user-friendly command-line
 interfaces. The program defines what arguments it requires, and :mod:`argparse`
@@ -103,9 +107,9 @@ or the :func:`max` function if it was not.
 Parsing arguments
 ^^^^^^^^^^^^^^^^^
 
-:class:`ArgumentParser` parses args through the
+:class:`ArgumentParser` parses arguments through the
 :meth:`~ArgumentParser.parse_args` method.  This will inspect the command line,
-convert each arg to the appropriate type and then invoke the appropriate action.
+convert each argument to the appropriate type and then invoke the appropriate action.
 In most cases, this means a simple :class:`Namespace` object will be built up from
 attributes parsed out of the command line::
 
@@ -114,7 +118,7 @@ attributes parsed out of the command line::
 
 In a script, :meth:`~ArgumentParser.parse_args` will typically be called with no
 arguments, and the :class:`ArgumentParser` will automatically determine the
-command-line args from :data:`sys.argv`.
+command-line arguments from :data:`sys.argv`.
 
 
 ArgumentParser objects
@@ -238,7 +242,7 @@ This can be achieved by passing ``False`` as the ``add_help=`` argument to
     --foo FOO  foo help
 
 The help option is typically ``-h/--help``. The exception to this is
-if the ``prefix_chars=`` is specified and does not include ``'-'``, in
+if the ``prefix_chars=`` is specified and does not include ``-``, in
 which case ``-h`` and ``--help`` are not valid options.  In
 this case, the first character in ``prefix_chars`` is used to prefix
 the help options::
@@ -254,7 +258,7 @@ the help options::
 prefix_chars
 ^^^^^^^^^^^^
 
-Most command-line options will use ``'-'`` as the prefix, e.g. ``-f/--foo``.
+Most command-line options will use ``-`` as the prefix, e.g. ``-f/--foo``.
 Parsers that need to support different or additional prefix
 characters, e.g. for options
 like ``+f`` or ``/foo``, may specify them using the ``prefix_chars=`` argument
@@ -267,7 +271,7 @@ to the ArgumentParser constructor::
    Namespace(bar='Y', f='X')
 
 The ``prefix_chars=`` argument defaults to ``'-'``. Supplying a set of
-characters that does not include ``'-'`` will cause ``-f/--foo`` options to be
+characters that does not include ``-`` will cause ``-f/--foo`` options to be
 disallowed.
 
 
@@ -389,7 +393,7 @@ epilog_ texts in command-line help messages::
    likewise for this epilog whose whitespace will be cleaned up and whose words
    will be wrapped across a couple lines
 
-Passing :class:`~argparse.RawDescriptionHelpFormatter` as ``formatter_class=``
+Passing :class:`RawDescriptionHelpFormatter` as ``formatter_class=``
 indicates that description_ and epilog_ are already correctly formatted and
 should not be line-wrapped::
 
@@ -415,7 +419,7 @@ should not be line-wrapped::
    optional arguments:
     -h, --help  show this help message and exit
 
-:class:`RawTextHelpFormatter` maintains whitespace for all sorts of help text
+:class:`RawTextHelpFormatter` maintains whitespace for all sorts of help text,
 including argument descriptions.
 
 The other formatter class available, :class:`ArgumentDefaultsHelpFormatter`,
@@ -642,11 +646,11 @@ be positional::
 action
 ^^^^^^
 
-:class:`ArgumentParser` objects associate command-line args with actions.  These
-actions can do just about anything with the command-line args associated with
+:class:`ArgumentParser` objects associate command-line arguments with actions.  These
+actions can do just about anything with the command-line arguments associated with
 them, though most actions simply add an attribute to the object returned by
 :meth:`~ArgumentParser.parse_args`.  The ``action`` keyword argument specifies
-how the command-line args should be handled. The supported actions are:
+how the command-line arguments should be handled. The supported actions are:
 
 * ``'store'`` - This just stores the argument's value.  This is the default
   action. For example::
@@ -718,8 +722,8 @@ the Action API.  The easiest way to do this is to extend
   :meth:`~ArgumentParser.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
+* ``values`` - The associated command-line arguments, with any type conversions
+  applied.  (Type conversions are specified with the type_ keyword argument to
   :meth:`~ArgumentParser.add_argument`.
 
 * ``option_string`` - The option string that was used to invoke this action.
@@ -751,7 +755,7 @@ single action to be taken.  The ``nargs`` keyword argument associates a
 different number of command-line arguments with a single action.  The supported
 values are:
 
-* N (an integer).  N args from the command line will be gathered together into a
+* ``N`` (an integer).  ``N`` arguments from the command line will be gathered together into a
   list.  For example::
 
      >>> parser = argparse.ArgumentParser()
@@ -763,11 +767,11 @@ values are:
   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
+* ``'?'``. One argument will be consumed from the command line if possible, and
+  produced as a single item.  If no command-line argument 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
+  command-line argument.  In this case the value from const_ will be produced.  Some
   examples to illustrate this::
 
      >>> parser = argparse.ArgumentParser()
@@ -795,7 +799,7 @@ values are:
      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
+* ``'*'``.  All command-line arguments 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::
@@ -809,7 +813,7 @@ values are:
 
 * ``'+'``. 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::
+  least one command-line argument present.  For example::
 
      >>> parser = argparse.ArgumentParser(prog='PROG')
      >>> parser.add_argument('foo', nargs='+')
@@ -819,8 +823,8 @@ values are:
      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
+If the ``nargs`` keyword argument is not provided, the number of arguments consumed
+is determined by the action_.  Generally this means a single command-line argument
 will be consumed and a single item (not a list) will be produced.
 
 
@@ -837,9 +841,9 @@ the various :class:`ArgumentParser` actions.  The two most common uses of it are
 
 * When :meth:`~ArgumentParser.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.
+  argument that can be followed by zero or one command-line arguments.
   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.
+  command-line argument following it, the value of ``const`` will be assumed instead.
   See the nargs_ description for examples.
 
 The ``const`` keyword argument defaults to ``None``.
@@ -851,7 +855,7 @@ default
 All optional arguments and some positional arguments may be omitted at the
 command line.  The ``default`` keyword argument of
 :meth:`~ArgumentParser.add_argument`, whose value defaults to ``None``,
-specifies what value should be used if the command-line arg is not present.
+specifies what value should be used if the command-line argument is not present.
 For optional arguments, the ``default`` value is used when the option string
 was not present at the command line::
 
@@ -862,8 +866,8 @@ was not present at the command line::
    >>> 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::
+For positional arguments with nargs_ equal to ``?`` or ``*``, the ``default`` value
+is used when no command-line argument was present::
 
    >>> parser = argparse.ArgumentParser()
    >>> parser.add_argument('foo', nargs='?', default=42)
@@ -887,12 +891,12 @@ command-line argument was not present.::
 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, like a :class:`float`, :class:`int` or :class:`file`.  The
+By default, :class:`ArgumentParser` objects read command-line arguments in as simple
+strings. However, quite often the command-line string should instead be
+interpreted as another type, like a :class:`float` or :class:`int`.  The
 ``type`` keyword argument of :meth:`~ArgumentParser.add_argument` allows any
-necessary type-checking and type-conversions to be performed.  Many common
-built-in types can be used directly as the value of the ``type`` argument::
+necessary type-checking and type conversions to be performed.  Common built-in
+types and functions can be used directly as the value of the ``type`` argument::
 
    >>> parser = argparse.ArgumentParser()
    >>> parser.add_argument('foo', type=int)
@@ -911,7 +915,7 @@ writable file::
    Namespace(bar=<open file 'out.txt', mode 'w' at 0x...>)
 
 ``type=`` can take any callable that takes a single string argument and returns
-the type-converted value::
+the converted value::
 
    >>> def perfect_square(string):
    ...     value = int(string)
@@ -946,11 +950,11 @@ See the choices_ section for more details.
 choices
 ^^^^^^^
 
-Some command-line args should be selected from a restricted set of values.
+Some command-line arguments should be selected from a restricted set of values.
 These can be handled by passing a container object as the ``choices`` keyword
 argument to :meth:`~ArgumentParser.add_argument`.  When the command line is
-parsed, arg values will be checked, and an error message will be displayed if
-the arg was not one of the acceptable values::
+parsed, argument values will be checked, and an error message will be displayed if
+the argument was not one of the acceptable values::
 
    >>> parser = argparse.ArgumentParser(prog='PROG')
    >>> parser.add_argument('foo', choices='abc')
@@ -1053,7 +1057,7 @@ 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, a single positional argument with
 ``dest='bar'`` will that argument will be referred to as ``bar``. A single
-optional argument ``--foo`` that should be followed by a single command-line arg
+optional argument ``--foo`` that should be followed by a single command-line argument
 will be referred to as ``FOO``.  An example::
 
    >>> parser = argparse.ArgumentParser()
@@ -1125,10 +1129,10 @@ attribute is determined by the ``dest`` keyword argument of
 
 For optional argument actions, the value of ``dest`` is normally inferred from
 the option strings.  :class:`ArgumentParser` generates the value of ``dest`` by
-taking the first long option string and stripping away the initial ``'--'``
+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 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::
 
@@ -1160,7 +1164,7 @@ The parse_args() method
    created and how they are assigned. See the documentation for
    :meth:`add_argument` for details.
 
-   By default, the arg strings are taken from :data:`sys.argv`, and a new empty
+   By default, the argument strings are taken from :data:`sys.argv`, and a new empty
    :class:`Namespace` object is created for the attributes.
 
 
@@ -1231,15 +1235,15 @@ it exits and prints the error along with a usage message::
    PROG: error: extra arguments found: badger
 
 
-Arguments containing ``"-"``
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+Arguments containing ``-``
+^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 The :meth:`~ArgumentParser.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
+ambiguous.  For example, the command-line argument ``-1`` could either be an
 attempt to specify an option or an attempt to provide a positional argument.
 The :meth:`~ArgumentParser.parse_args` method is cautious here: positional
-arguments may only begin with ``'-'`` if they look like negative numbers and
+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')
@@ -1272,7 +1276,7 @@ there are no options in the parser that look like negative numbers::
    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
+If you have positional arguments that must begin with ``-`` and don't look
 like negative numbers, you can insert the pseudo-argument ``'--'`` which tells
 :meth:`~ArgumentParser.parse_args` that everything after that is a positional
 argument::
@@ -1304,7 +1308,7 @@ An error is produced for arguments that could produce more than one options.
 Beyond ``sys.argv``
 ^^^^^^^^^^^^^^^^^^^
 
-Sometimes it may be useful to have an ArgumentParser parse args other than those
+Sometimes it may be useful to have an ArgumentParser parse arguments other than those
 of :data:`sys.argv`.  This can be accomplished by passing a list of strings to
 :meth:`~ArgumentParser.parse_args`.  This is useful for testing at the
 interactive prompt::
@@ -1390,7 +1394,7 @@ Sub-commands
      >>> parser_b = subparsers.add_parser('b', help='b help')
      >>> parser_b.add_argument('--baz', choices='XYZ', help='baz help')
      >>>
-     >>> # parse some arg lists
+     >>> # parse some argument lists
      >>> parser.parse_args(['a', '12'])
      Namespace(bar=12, foo=False)
      >>> parser.parse_args(['--foo', 'b', '--baz', 'Z'])
@@ -1399,8 +1403,8 @@ Sub-commands
    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
+   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
@@ -1522,7 +1526,7 @@ FileType objects
 
    The :class:`FileType` factory creates objects that can be passed to the type
    argument of :meth:`ArgumentParser.add_argument`.  Arguments that have
-   :class:`FileType` objects as their type will open command-line args as files
+   :class:`FileType` objects as their type will open command-line arguments as files
    with the requested modes and buffer sizes:
 
    >>> parser = argparse.ArgumentParser()
@@ -1636,7 +1640,7 @@ Parser defaults
 .. method:: ArgumentParser.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
+   will be fully determined by inspecting the command-line arguments and the argument
    actions.  :meth:`set_defaults` allows some additional
    attributes that are determined without any inspection of the command line to
    be added::