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oasis-root

Compiled tree of Oasis Linux based on own branch at <https://hacktivis.me/git/oasis/> git clone https://anongit.hacktivis.me/git/oasis-root.git

argparse.py (97785B)

    

  1. # Author: Steven J. Bethard <steven.bethard@gmail.com>.
  2. # New maintainer as of 29 August 2019:  Raymond Hettinger <raymond.hettinger@gmail.com>
  4. """Command-line parsing library
  6. This module is an optparse-inspired command-line parsing library that:
  8.     - handles both optional and positional arguments
  9.     - produces highly informative usage messages
  10.     - supports parsers that dispatch to sub-parsers
  12. The following is a simple usage example that sums integers from the
  13. command-line and writes the result to a file::
  15.     parser = argparse.ArgumentParser(
  16.         description='sum the integers at the command line')
  17.     parser.add_argument(
  18.         'integers', metavar='int', nargs='+', type=int,
  19.         help='an integer to be summed')
  20.     parser.add_argument(
  21.         '--log', default=sys.stdout, type=argparse.FileType('w'),
  22.         help='the file where the sum should be written')
  23.     args = parser.parse_args()
  24.     args.log.write('%s' % sum(args.integers))
  25.     args.log.close()
  27. The module contains the following public classes:
  29.     - ArgumentParser -- The main entry point for command-line parsing. As the
  30.         example above shows, the add_argument() method is used to populate
  31.         the parser with actions for optional and positional arguments. Then
  32.         the parse_args() method is invoked to convert the args at the
  33.         command-line into an object with attributes.
  35.     - ArgumentError -- The exception raised by ArgumentParser objects when
  36.         there are errors with the parser's actions. Errors raised while
  37.         parsing the command-line are caught by ArgumentParser and emitted
  38.         as command-line messages.
  40.     - FileType -- A factory for defining types of files to be created. As the
  41.         example above shows, instances of FileType are typically passed as
  42.         the type= argument of add_argument() calls.
  44.     - Action -- The base class for parser actions. Typically actions are
  45.         selected by passing strings like 'store_true' or 'append_const' to
  46.         the action= argument of add_argument(). However, for greater
  47.         customization of ArgumentParser actions, subclasses of Action may
  48.         be defined and passed as the action= argument.
  50.     - HelpFormatter, RawDescriptionHelpFormatter, RawTextHelpFormatter,
  51.         ArgumentDefaultsHelpFormatter -- Formatter classes which
  52.         may be passed as the formatter_class= argument to the
  53.         ArgumentParser constructor. HelpFormatter is the default,
  54.         RawDescriptionHelpFormatter and RawTextHelpFormatter tell the parser
  55.         not to change the formatting for help text, and
  56.         ArgumentDefaultsHelpFormatter adds information about argument defaults
  57.         to the help.
  59. All other classes in this module are considered implementation details.
  60. (Also note that HelpFormatter and RawDescriptionHelpFormatter are only
  61. considered public as object names -- the API of the formatter objects is
  62. still considered an implementation detail.)
  63. """
  65. __version__ = '1.1'
  66. __all__ = [
  67.     'ArgumentParser',
  68.     'ArgumentError',
  69.     'ArgumentTypeError',
  70.     'BooleanOptionalAction',
  71.     'FileType',
  72.     'HelpFormatter',
  73.     'ArgumentDefaultsHelpFormatter',
  74.     'RawDescriptionHelpFormatter',
  75.     'RawTextHelpFormatter',
  76.     'MetavarTypeHelpFormatter',
  77.     'Namespace',
  78.     'Action',
  79.     'ONE_OR_MORE',
  80.     'OPTIONAL',
  81.     'PARSER',
  82.     'REMAINDER',
  83.     'SUPPRESS',
  84.     'ZERO_OR_MORE',
  85. ]
  88. import os as _os
  89. import re as _re
  90. import sys as _sys
  92. from gettext import gettext as _, ngettext
  94. SUPPRESS = '==SUPPRESS=='
  96. OPTIONAL = '?'
  97. ZERO_OR_MORE = '*'
  98. ONE_OR_MORE = '+'
  99. PARSER = 'A...'
  100. REMAINDER = '...'
  101. _UNRECOGNIZED_ARGS_ATTR = '_unrecognized_args'
  103. # =============================
  104. # Utility functions and classes
  105. # =============================
  107. class _AttributeHolder(object):
  108.     """Abstract base class that provides __repr__.
  110.     The __repr__ method returns a string in the format::
  111.         ClassName(attr=name, attr=name, ...)
  112.     The attributes are determined either by a class-level attribute,
  113.     '_kwarg_names', or by inspecting the instance __dict__.
  114.     """
  116.     def __repr__(self):
  117.         type_name = type(self).__name__
  118.         arg_strings = []
  119.         star_args = {}
  120.         for arg in self._get_args():
  121.             arg_strings.append(repr(arg))
  122.         for name, value in self._get_kwargs():
  123.             if name.isidentifier():
  124.                 arg_strings.append('%s=%r' % (name, value))
  125.             else:
  126.                 star_args[name] = value
  127.         if star_args:
  128.             arg_strings.append('**%s' % repr(star_args))
  129.         return '%s(%s)' % (type_name, ', '.join(arg_strings))
  131.     def _get_kwargs(self):
  132.         return list(self.__dict__.items())
  134.     def _get_args(self):
  135.         return []
  138. def _copy_items(items):
  139.     if items is None:
  140.         return []
  141.     # The copy module is used only in the 'append' and 'append_const'
  142.     # actions, and it is needed only when the default value isn't a list.
  143.     # Delay its import for speeding up the common case.
  144.     if type(items) is list:
  145.         return items[:]
  146.     import copy
  147.     return copy.copy(items)
  150. # ===============
  151. # Formatting Help
  152. # ===============
  154. class HelpFormatter(object):
  155.     """Formatter for generating usage messages and argument help strings.
  157.     Only the name of this class is considered a public API. All the methods
  158.     provided by the class are considered an implementation detail.
  159.     """
  161.     def __init__(self,
  162.                  prog,
  163.                  indent_increment=2,
  164.                  max_help_position=24,
  165.                  width=None):
  167.         # default setting for width
  168.         if width is None:
  169.             import shutil
  170.             width = shutil.get_terminal_size().columns
  171.             width -= 2
  173.         self._prog = prog
  174.         self._indent_increment = indent_increment
  175.         self._max_help_position = min(max_help_position,
  176.                                       max(width - 20, indent_increment * 2))
  177.         self._width = width
  179.         self._current_indent = 0
  180.         self._level = 0
  181.         self._action_max_length = 0
  183.         self._root_section = self._Section(self, None)
  184.         self._current_section = self._root_section
  186.         self._whitespace_matcher = _re.compile(r'\s+', _re.ASCII)
  187.         self._long_break_matcher = _re.compile(r'\n\n\n+')
  189.     # ===============================
  190.     # Section and indentation methods
  191.     # ===============================
  192.     def _indent(self):
  193.         self._current_indent += self._indent_increment
  194.         self._level += 1
  196.     def _dedent(self):
  197.         self._current_indent -= self._indent_increment
  198.         assert self._current_indent >= 0, 'Indent decreased below 0.'
  199.         self._level -= 1
  201.     class _Section(object):
  203.         def __init__(self, formatter, parent, heading=None):
  204.             self.formatter = formatter
  205.             self.parent = parent
  206.             self.heading = heading
  207.             self.items = []
  209.         def format_help(self):
  210.             # format the indented section
  211.             if self.parent is not None:
  212.                 self.formatter._indent()
  213.             join = self.formatter._join_parts
  214.             item_help = join([func(*args) for func, args in self.items])
  215.             if self.parent is not None:
  216.                 self.formatter._dedent()
  218.             # return nothing if the section was empty
  219.             if not item_help:
  220.                 return ''
  222.             # add the heading if the section was non-empty
  223.             if self.heading is not SUPPRESS and self.heading is not None:
  224.                 current_indent = self.formatter._current_indent
  225.                 heading = '%*s%s:\n' % (current_indent, '', self.heading)
  226.             else:
  227.                 heading = ''
  229.             # join the section-initial newline, the heading and the help
  230.             return join(['\n', heading, item_help, '\n'])
  232.     def _add_item(self, func, args):
  233.         self._current_section.items.append((func, args))
  235.     # ========================
  236.     # Message building methods
  237.     # ========================
  238.     def start_section(self, heading):
  239.         self._indent()
  240.         section = self._Section(self, self._current_section, heading)
  241.         self._add_item(section.format_help, [])
  242.         self._current_section = section
  244.     def end_section(self):
  245.         self._current_section = self._current_section.parent
  246.         self._dedent()
  248.     def add_text(self, text):
  249.         if text is not SUPPRESS and text is not None:
  250.             self._add_item(self._format_text, [text])
  252.     def add_usage(self, usage, actions, groups, prefix=None):
  253.         if usage is not SUPPRESS:
  254.             args = usage, actions, groups, prefix
  255.             self._add_item(self._format_usage, args)
  257.     def add_argument(self, action):
  258.         if action.help is not SUPPRESS:
  260.             # find all invocations
  261.             get_invocation = self._format_action_invocation
  262.             invocations = [get_invocation(action)]
  263.             for subaction in self._iter_indented_subactions(action):
  264.                 invocations.append(get_invocation(subaction))
  266.             # update the maximum item length
  267.             invocation_length = max(map(len, invocations))
  268.             action_length = invocation_length + self._current_indent
  269.             self._action_max_length = max(self._action_max_length,
  270.                                           action_length)
  272.             # add the item to the list
  273.             self._add_item(self._format_action, [action])
  275.     def add_arguments(self, actions):
  276.         for action in actions:
  277.             self.add_argument(action)
  279.     # =======================
  280.     # Help-formatting methods
  281.     # =======================
  282.     def format_help(self):
  283.         help = self._root_section.format_help()
  284.         if help:
  285.             help = self._long_break_matcher.sub('\n\n', help)
  286.             help = help.strip('\n') + '\n'
  287.         return help
  289.     def _join_parts(self, part_strings):
  290.         return ''.join([part
  291.                         for part in part_strings
  292.                         if part and part is not SUPPRESS])
  294.     def _format_usage(self, usage, actions, groups, prefix):
  295.         if prefix is None:
  296.             prefix = _('usage: ')
  298.         # if usage is specified, use that
  299.         if usage is not None:
  300.             usage = usage % dict(prog=self._prog)
  302.         # if no optionals or positionals are available, usage is just prog
  303.         elif usage is None and not actions:
  304.             usage = '%(prog)s' % dict(prog=self._prog)
  306.         # if optionals and positionals are available, calculate usage
  307.         elif usage is None:
  308.             prog = '%(prog)s' % dict(prog=self._prog)
  310.             # split optionals from positionals
  311.             optionals = []
  312.             positionals = []
  313.             for action in actions:
  314.                 if action.option_strings:
  315.                     optionals.append(action)
  316.                 else:
  317.                     positionals.append(action)
  319.             # build full usage string
  320.             format = self._format_actions_usage
  321.             action_usage = format(optionals + positionals, groups)
  322.             usage = ' '.join([s for s in [prog, action_usage] if s])
  324.             # wrap the usage parts if it's too long
  325.             text_width = self._width - self._current_indent
  326.             if len(prefix) + len(usage) > text_width:
  328.                 # break usage into wrappable parts
  329.                 part_regexp = (
  330.                     r'\(.*?\)+(?=\s|$)|'
  331.                     r'\[.*?\]+(?=\s|$)|'
  332.                     r'\S+'
  333.                 )
  334.                 opt_usage = format(optionals, groups)
  335.                 pos_usage = format(positionals, groups)
  336.                 opt_parts = _re.findall(part_regexp, opt_usage)
  337.                 pos_parts = _re.findall(part_regexp, pos_usage)
  338.                 assert ' '.join(opt_parts) == opt_usage
  339.                 assert ' '.join(pos_parts) == pos_usage
  341.                 # helper for wrapping lines
  342.                 def get_lines(parts, indent, prefix=None):
  343.                     lines = []
  344.                     line = []
  345.                     if prefix is not None:
  346.                         line_len = len(prefix) - 1
  347.                     else:
  348.                         line_len = len(indent) - 1
  349.                     for part in parts:
  350.                         if line_len + 1 + len(part) > text_width and line:
  351.                             lines.append(indent + ' '.join(line))
  352.                             line = []
  353.                             line_len = len(indent) - 1
  354.                         line.append(part)
  355.                         line_len += len(part) + 1
  356.                     if line:
  357.                         lines.append(indent + ' '.join(line))
  358.                     if prefix is not None:
  359.                         lines[0] = lines[0][len(indent):]
  360.                     return lines
  362.                 # if prog is short, follow it with optionals or positionals
  363.                 if len(prefix) + len(prog) <= 0.75 * text_width:
  364.                     indent = ' ' * (len(prefix) + len(prog) + 1)
  365.                     if opt_parts:
  366.                         lines = get_lines([prog] + opt_parts, indent, prefix)
  367.                         lines.extend(get_lines(pos_parts, indent))
  368.                     elif pos_parts:
  369.                         lines = get_lines([prog] + pos_parts, indent, prefix)
  370.                     else:
  371.                         lines = [prog]
  373.                 # if prog is long, put it on its own line
  374.                 else:
  375.                     indent = ' ' * len(prefix)
  376.                     parts = opt_parts + pos_parts
  377.                     lines = get_lines(parts, indent)
  378.                     if len(lines) > 1:
  379.                         lines = []
  380.                         lines.extend(get_lines(opt_parts, indent))
  381.                         lines.extend(get_lines(pos_parts, indent))
  382.                     lines = [prog] + lines
  384.                 # join lines into usage
  385.                 usage = '\n'.join(lines)
  387.         # prefix with 'usage:'
  388.         return '%s%s\n\n' % (prefix, usage)
  390.     def _format_actions_usage(self, actions, groups):
  391.         # find group indices and identify actions in groups
  392.         group_actions = set()
  393.         inserts = {}
  394.         for group in groups:
  395.             try:
  396.                 start = actions.index(group._group_actions[0])
  397.             except ValueError:
  398.                 continue
  399.             else:
  400.                 end = start + len(group._group_actions)
  401.                 if actions[start:end] == group._group_actions:
  402.                     for action in group._group_actions:
  403.                         group_actions.add(action)
  404.                     if not group.required:
  405.                         if start in inserts:
  406.                             inserts[start] += ' ['
  407.                         else:
  408.                             inserts[start] = '['
  409.                         if end in inserts:
  410.                             inserts[end] += ']'
  411.                         else:
  412.                             inserts[end] = ']'
  413.                     else:
  414.                         if start in inserts:
  415.                             inserts[start] += ' ('
  416.                         else:
  417.                             inserts[start] = '('
  418.                         if end in inserts:
  419.                             inserts[end] += ')'
  420.                         else:
  421.                             inserts[end] = ')'
  422.                     for i in range(start + 1, end):
  423.                         inserts[i] = '|'
  425.         # collect all actions format strings
  426.         parts = []
  427.         for i, action in enumerate(actions):
  429.             # suppressed arguments are marked with None
  430.             # remove | separators for suppressed arguments
  431.             if action.help is SUPPRESS:
  432.                 parts.append(None)
  433.                 if inserts.get(i) == '|':
  434.                     inserts.pop(i)
  435.                 elif inserts.get(i + 1) == '|':
  436.                     inserts.pop(i + 1)
  438.             # produce all arg strings
  439.             elif not action.option_strings:
  440.                 default = self._get_default_metavar_for_positional(action)
  441.                 part = self._format_args(action, default)
  443.                 # if it's in a group, strip the outer []
  444.                 if action in group_actions:
  445.                     if part[0] == '[' and part[-1] == ']':
  446.                         part = part[1:-1]
  448.                 # add the action string to the list
  449.                 parts.append(part)
  451.             # produce the first way to invoke the option in brackets
  452.             else:
  453.                 option_string = action.option_strings[0]
  455.                 # if the Optional doesn't take a value, format is:
  456.                 #    -s or --long
  457.                 if action.nargs == 0:
  458.                     part = action.format_usage()
  460.                 # if the Optional takes a value, format is:
  461.                 #    -s ARGS or --long ARGS
  462.                 else:
  463.                     default = self._get_default_metavar_for_optional(action)
  464.                     args_string = self._format_args(action, default)
  465.                     part = '%s %s' % (option_string, args_string)
  467.                 # make it look optional if it's not required or in a group
  468.                 if not action.required and action not in group_actions:
  469.                     part = '[%s]' % part
  471.                 # add the action string to the list
  472.                 parts.append(part)
  474.         # insert things at the necessary indices
  475.         for i in sorted(inserts, reverse=True):
  476.             parts[i:i] = [inserts[i]]
  478.         # join all the action items with spaces
  479.         text = ' '.join([item for item in parts if item is not None])
  481.         # clean up separators for mutually exclusive groups
  482.         open = r'[\[(]'
  483.         close = r'[\])]'
  484.         text = _re.sub(r'(%s) ' % open, r'\1', text)
  485.         text = _re.sub(r' (%s)' % close, r'\1', text)
  486.         text = _re.sub(r'%s *%s' % (open, close), r'', text)
  487.         text = _re.sub(r'\(([^|]*)\)', r'\1', text)
  488.         text = text.strip()
  490.         # return the text
  491.         return text
  493.     def _format_text(self, text):
  494.         if '%(prog)' in text:
  495.             text = text % dict(prog=self._prog)
  496.         text_width = max(self._width - self._current_indent, 11)
  497.         indent = ' ' * self._current_indent
  498.         return self._fill_text(text, text_width, indent) + '\n\n'
  500.     def _format_action(self, action):
  501.         # determine the required width and the entry label
  502.         help_position = min(self._action_max_length + 2,
  503.                             self._max_help_position)
  504.         help_width = max(self._width - help_position, 11)
  505.         action_width = help_position - self._current_indent - 2
  506.         action_header = self._format_action_invocation(action)
  508.         # no help; start on same line and add a final newline
  509.         if not action.help:
  510.             tup = self._current_indent, '', action_header
  511.             action_header = '%*s%s\n' % tup
  513.         # short action name; start on the same line and pad two spaces
  514.         elif len(action_header) <= action_width:
  515.             tup = self._current_indent, '', action_width, action_header
  516.             action_header = '%*s%-*s  ' % tup
  517.             indent_first = 0
  519.         # long action name; start on the next line
  520.         else:
  521.             tup = self._current_indent, '', action_header
  522.             action_header = '%*s%s\n' % tup
  523.             indent_first = help_position
  525.         # collect the pieces of the action help
  526.         parts = [action_header]
  528.         # if there was help for the action, add lines of help text
  529.         if action.help:
  530.             help_text = self._expand_help(action)
  531.             help_lines = self._split_lines(help_text, help_width)
  532.             parts.append('%*s%s\n' % (indent_first, '', help_lines[0]))
  533.             for line in help_lines[1:]:
  534.                 parts.append('%*s%s\n' % (help_position, '', line))
  536.         # or add a newline if the description doesn't end with one
  537.         elif not action_header.endswith('\n'):
  538.             parts.append('\n')
  540.         # if there are any sub-actions, add their help as well
  541.         for subaction in self._iter_indented_subactions(action):
  542.             parts.append(self._format_action(subaction))
  544.         # return a single string
  545.         return self._join_parts(parts)
  547.     def _format_action_invocation(self, action):
  548.         if not action.option_strings:
  549.             default = self._get_default_metavar_for_positional(action)
  550.             metavar, = self._metavar_formatter(action, default)(1)
  551.             return metavar
  553.         else:
  554.             parts = []
  556.             # if the Optional doesn't take a value, format is:
  557.             #    -s, --long
  558.             if action.nargs == 0:
  559.                 parts.extend(action.option_strings)
  561.             # if the Optional takes a value, format is:
  562.             #    -s ARGS, --long ARGS
  563.             else:
  564.                 default = self._get_default_metavar_for_optional(action)
  565.                 args_string = self._format_args(action, default)
  566.                 for option_string in action.option_strings:
  567.                     parts.append('%s %s' % (option_string, args_string))
  569.             return ', '.join(parts)
  571.     def _metavar_formatter(self, action, default_metavar):
  572.         if action.metavar is not None:
  573.             result = action.metavar
  574.         elif action.choices is not None:
  575.             choice_strs = [str(choice) for choice in action.choices]
  576.             result = '{%s}' % ','.join(choice_strs)
  577.         else:
  578.             result = default_metavar
  580.         def format(tuple_size):
  581.             if isinstance(result, tuple):
  582.                 return result
  583.             else:
  584.                 return (result, ) * tuple_size
  585.         return format
  587.     def _format_args(self, action, default_metavar):
  588.         get_metavar = self._metavar_formatter(action, default_metavar)
  589.         if action.nargs is None:
  590.             result = '%s' % get_metavar(1)
  591.         elif action.nargs == OPTIONAL:
  592.             result = '[%s]' % get_metavar(1)
  593.         elif action.nargs == ZERO_OR_MORE:
  594.             metavar = get_metavar(1)
  595.             if len(metavar) == 2:
  596.                 result = '[%s [%s ...]]' % metavar
  597.             else:
  598.                 result = '[%s ...]' % metavar
  599.         elif action.nargs == ONE_OR_MORE:
  600.             result = '%s [%s ...]' % get_metavar(2)
  601.         elif action.nargs == REMAINDER:
  602.             result = '...'
  603.         elif action.nargs == PARSER:
  604.             result = '%s ...' % get_metavar(1)
  605.         elif action.nargs == SUPPRESS:
  606.             result = ''
  607.         else:
  608.             try:
  609.                 formats = ['%s' for _ in range(action.nargs)]
  610.             except TypeError:
  611.                 raise ValueError("invalid nargs value") from None
  612.             result = ' '.join(formats) % get_metavar(action.nargs)
  613.         return result
  615.     def _expand_help(self, action):
  616.         params = dict(vars(action), prog=self._prog)
  617.         for name in list(params):
  618.             if params[name] is SUPPRESS:
  619.                 del params[name]
  620.         for name in list(params):
  621.             if hasattr(params[name], '__name__'):
  622.                 params[name] = params[name].__name__
  623.         if params.get('choices') is not None:
  624.             choices_str = ', '.join([str(c) for c in params['choices']])
  625.             params['choices'] = choices_str
  626.         return self._get_help_string(action) % params
  628.     def _iter_indented_subactions(self, action):
  629.         try:
  630.             get_subactions = action._get_subactions
  631.         except AttributeError:
  632.             pass
  633.         else:
  634.             self._indent()
  635.             yield from get_subactions()
  636.             self._dedent()
  638.     def _split_lines(self, text, width):
  639.         text = self._whitespace_matcher.sub(' ', text).strip()
  640.         # The textwrap module is used only for formatting help.
  641.         # Delay its import for speeding up the common usage of argparse.
  642.         import textwrap
  643.         return textwrap.wrap(text, width)
  645.     def _fill_text(self, text, width, indent):
  646.         text = self._whitespace_matcher.sub(' ', text).strip()
  647.         import textwrap
  648.         return textwrap.fill(text, width,
  649.                              initial_indent=indent,
  650.                              subsequent_indent=indent)
  652.     def _get_help_string(self, action):
  653.         return action.help
  655.     def _get_default_metavar_for_optional(self, action):
  656.         return action.dest.upper()
  658.     def _get_default_metavar_for_positional(self, action):
  659.         return action.dest
  662. class RawDescriptionHelpFormatter(HelpFormatter):
  663.     """Help message formatter which retains any formatting in descriptions.
  665.     Only the name of this class is considered a public API. All the methods
  666.     provided by the class are considered an implementation detail.
  667.     """
  669.     def _fill_text(self, text, width, indent):
  670.         return ''.join(indent + line for line in text.splitlines(keepends=True))
  673. class RawTextHelpFormatter(RawDescriptionHelpFormatter):
  674.     """Help message formatter which retains formatting of all help text.
  676.     Only the name of this class is considered a public API. All the methods
  677.     provided by the class are considered an implementation detail.
  678.     """
  680.     def _split_lines(self, text, width):
  681.         return text.splitlines()
  684. class ArgumentDefaultsHelpFormatter(HelpFormatter):
  685.     """Help message formatter which adds default values to argument help.
  687.     Only the name of this class is considered a public API. All the methods
  688.     provided by the class are considered an implementation detail.
  689.     """
  691.     def _get_help_string(self, action):
  692.         help = action.help
  693.         if '%(default)' not in action.help:
  694.             if action.default is not SUPPRESS:
  695.                 defaulting_nargs = [OPTIONAL, ZERO_OR_MORE]
  696.                 if action.option_strings or action.nargs in defaulting_nargs:
  697.                     help += ' (default: %(default)s)'
  698.         return help
  701. class MetavarTypeHelpFormatter(HelpFormatter):
  702.     """Help message formatter which uses the argument 'type' as the default
  703.     metavar value (instead of the argument 'dest')
  705.     Only the name of this class is considered a public API. All the methods
  706.     provided by the class are considered an implementation detail.
  707.     """
  709.     def _get_default_metavar_for_optional(self, action):
  710.         return action.type.__name__
  712.     def _get_default_metavar_for_positional(self, action):
  713.         return action.type.__name__
  717. # =====================
  718. # Options and Arguments
  719. # =====================
  721. def _get_action_name(argument):
  722.     if argument is None:
  723.         return None
  724.     elif argument.option_strings:
  725.         return  '/'.join(argument.option_strings)
  726.     elif argument.metavar not in (None, SUPPRESS):
  727.         return argument.metavar
  728.     elif argument.dest not in (None, SUPPRESS):
  729.         return argument.dest
  730.     elif argument.choices:
  731.         return '{' + ','.join(argument.choices) + '}'
  732.     else:
  733.         return None
  736. class ArgumentError(Exception):
  737.     """An error from creating or using an argument (optional or positional).
  739.     The string value of this exception is the message, augmented with
  740.     information about the argument that caused it.
  741.     """
  743.     def __init__(self, argument, message):
  744.         self.argument_name = _get_action_name(argument)
  745.         self.message = message
  747.     def __str__(self):
  748.         if self.argument_name is None:
  749.             format = '%(message)s'
  750.         else:
  751.             format = 'argument %(argument_name)s: %(message)s'
  752.         return format % dict(message=self.message,
  753.                              argument_name=self.argument_name)
  756. class ArgumentTypeError(Exception):
  757.     """An error from trying to convert a command line string to a type."""
  758.     pass
  761. # ==============
  762. # Action classes
  763. # ==============
  765. class Action(_AttributeHolder):
  766.     """Information about how to convert command line strings to Python objects.
  768.     Action objects are used by an ArgumentParser to represent the information
  769.     needed to parse a single argument from one or more strings from the
  770.     command line. The keyword arguments to the Action constructor are also
  771.     all attributes of Action instances.
  773.     Keyword Arguments:
  775.         - option_strings -- A list of command-line option strings which
  776.             should be associated with this action.
  778.         - dest -- The name of the attribute to hold the created object(s)
  780.         - nargs -- The number of command-line arguments that should be
  781.             consumed. By default, one argument will be consumed and a single
  782.             value will be produced.  Other values include:
  783.                 - N (an integer) consumes N arguments (and produces a list)
  784.                 - '?' consumes zero or one arguments
  785.                 - '*' consumes zero or more arguments (and produces a list)
  786.                 - '+' consumes one or more arguments (and produces a list)
  787.             Note that the difference between the default and nargs=1 is that
  788.             with the default, a single value will be produced, while with
  789.             nargs=1, a list containing a single value will be produced.
  791.         - const -- The value to be produced if the option is specified and the
  792.             option uses an action that takes no values.
  794.         - default -- The value to be produced if the option is not specified.
  796.         - type -- A callable that accepts a single string argument, and
  797.             returns the converted value.  The standard Python types str, int,
  798.             float, and complex are useful examples of such callables.  If None,
  799.             str is used.
  801.         - choices -- A container of values that should be allowed. If not None,
  802.             after a command-line argument has been converted to the appropriate
  803.             type, an exception will be raised if it is not a member of this
  804.             collection.
  806.         - required -- True if the action must always be specified at the
  807.             command line. This is only meaningful for optional command-line
  808.             arguments.
  810.         - help -- The help string describing the argument.
  812.         - metavar -- The name to be used for the option's argument with the
  813.             help string. If None, the 'dest' value will be used as the name.
  814.     """
  816.     def __init__(self,
  817.                  option_strings,
  818.                  dest,
  819.                  nargs=None,
  820.                  const=None,
  821.                  default=None,
  822.                  type=None,
  823.                  choices=None,
  824.                  required=False,
  825.                  help=None,
  826.                  metavar=None):
  827.         self.option_strings = option_strings
  828.         self.dest = dest
  829.         self.nargs = nargs
  830.         self.const = const
  831.         self.default = default
  832.         self.type = type
  833.         self.choices = choices
  834.         self.required = required
  835.         self.help = help
  836.         self.metavar = metavar
  838.     def _get_kwargs(self):
  839.         names = [
  840.             'option_strings',
  841.             'dest',
  842.             'nargs',
  843.             'const',
  844.             'default',
  845.             'type',
  846.             'choices',
  847.             'help',
  848.             'metavar',
  849.         ]
  850.         return [(name, getattr(self, name)) for name in names]
  852.     def format_usage(self):
  853.         return self.option_strings[0]
  855.     def __call__(self, parser, namespace, values, option_string=None):
  856.         raise NotImplementedError(_('.__call__() not defined'))
  858. class BooleanOptionalAction(Action):
  859.     def __init__(self,
  860.                  option_strings,
  861.                  dest,
  862.                  default=None,
  863.                  type=None,
  864.                  choices=None,
  865.                  required=False,
  866.                  help=None,
  867.                  metavar=None):
  869.         _option_strings = []
  870.         for option_string in option_strings:
  871.             _option_strings.append(option_string)
  873.             if option_string.startswith('--'):
  874.                 option_string = '--no-' + option_string[2:]
  875.                 _option_strings.append(option_string)
  877.         if help is not None and default is not None:
  878.             help += " (default: %(default)s)"
  880.         super().__init__(
  881.             option_strings=_option_strings,
  882.             dest=dest,
  883.             nargs=0,
  884.             default=default,
  885.             type=type,
  886.             choices=choices,
  887.             required=required,
  888.             help=help,
  889.             metavar=metavar)
  891.     def __call__(self, parser, namespace, values, option_string=None):
  892.         if option_string in self.option_strings:
  893.             setattr(namespace, self.dest, not option_string.startswith('--no-'))
  895.     def format_usage(self):
  896.         return ' | '.join(self.option_strings)
  899. class _StoreAction(Action):
  901.     def __init__(self,
  902.                  option_strings,
  903.                  dest,
  904.                  nargs=None,
  905.                  const=None,
  906.                  default=None,
  907.                  type=None,
  908.                  choices=None,
  909.                  required=False,
  910.                  help=None,
  911.                  metavar=None):
  912.         if nargs == 0:
  913.             raise ValueError('nargs for store actions must be != 0; if you '
  914.                              'have nothing to store, actions such as store '
  915.                              'true or store const may be more appropriate')
  916.         if const is not None and nargs != OPTIONAL:
  917.             raise ValueError('nargs must be %r to supply const' % OPTIONAL)
  918.         super(_StoreAction, self).__init__(
  919.             option_strings=option_strings,
  920.             dest=dest,
  921.             nargs=nargs,
  922.             const=const,
  923.             default=default,
  924.             type=type,
  925.             choices=choices,
  926.             required=required,
  927.             help=help,
  928.             metavar=metavar)
  930.     def __call__(self, parser, namespace, values, option_string=None):
  931.         setattr(namespace, self.dest, values)
  934. class _StoreConstAction(Action):
  936.     def __init__(self,
  937.                  option_strings,
  938.                  dest,
  939.                  const,
  940.                  default=None,
  941.                  required=False,
  942.                  help=None,
  943.                  metavar=None):
  944.         super(_StoreConstAction, self).__init__(
  945.             option_strings=option_strings,
  946.             dest=dest,
  947.             nargs=0,
  948.             const=const,
  949.             default=default,
  950.             required=required,
  951.             help=help)
  953.     def __call__(self, parser, namespace, values, option_string=None):
  954.         setattr(namespace, self.dest, self.const)
  957. class _StoreTrueAction(_StoreConstAction):
  959.     def __init__(self,
  960.                  option_strings,
  961.                  dest,
  962.                  default=False,
  963.                  required=False,
  964.                  help=None):
  965.         super(_StoreTrueAction, self).__init__(
  966.             option_strings=option_strings,
  967.             dest=dest,
  968.             const=True,
  969.             default=default,
  970.             required=required,
  971.             help=help)
  974. class _StoreFalseAction(_StoreConstAction):
  976.     def __init__(self,
  977.                  option_strings,
  978.                  dest,
  979.                  default=True,
  980.                  required=False,
  981.                  help=None):
  982.         super(_StoreFalseAction, self).__init__(
  983.             option_strings=option_strings,
  984.             dest=dest,
  985.             const=False,
  986.             default=default,
  987.             required=required,
  988.             help=help)
  991. class _AppendAction(Action):
  993.     def __init__(self,
  994.                  option_strings,
  995.                  dest,
  996.                  nargs=None,
  997.                  const=None,
  998.                  default=None,
  999.                  type=None,
  1000.                  choices=None,
  1001.                  required=False,
  1002.                  help=None,
  1003.                  metavar=None):
  1004.         if nargs == 0:
  1005.             raise ValueError('nargs for append actions must be != 0; if arg '
  1006.                              'strings are not supplying the value to append, '
  1007.                              'the append const action may be more appropriate')
  1008.         if const is not None and nargs != OPTIONAL:
  1009.             raise ValueError('nargs must be %r to supply const' % OPTIONAL)
  1010.         super(_AppendAction, self).__init__(
  1011.             option_strings=option_strings,
  1012.             dest=dest,
  1013.             nargs=nargs,
  1014.             const=const,
  1015.             default=default,
  1016.             type=type,
  1017.             choices=choices,
  1018.             required=required,
  1019.             help=help,
  1020.             metavar=metavar)
  1022.     def __call__(self, parser, namespace, values, option_string=None):
  1023.         items = getattr(namespace, self.dest, None)
  1024.         items = _copy_items(items)
  1025.         items.append(values)
  1026.         setattr(namespace, self.dest, items)
  1029. class _AppendConstAction(Action):
  1031.     def __init__(self,
  1032.                  option_strings,
  1033.                  dest,
  1034.                  const,
  1035.                  default=None,
  1036.                  required=False,
  1037.                  help=None,
  1038.                  metavar=None):
  1039.         super(_AppendConstAction, self).__init__(
  1040.             option_strings=option_strings,
  1041.             dest=dest,
  1042.             nargs=0,
  1043.             const=const,
  1044.             default=default,
  1045.             required=required,
  1046.             help=help,
  1047.             metavar=metavar)
  1049.     def __call__(self, parser, namespace, values, option_string=None):
  1050.         items = getattr(namespace, self.dest, None)
  1051.         items = _copy_items(items)
  1052.         items.append(self.const)
  1053.         setattr(namespace, self.dest, items)
  1056. class _CountAction(Action):
  1058.     def __init__(self,
  1059.                  option_strings,
  1060.                  dest,
  1061.                  default=None,
  1062.                  required=False,
  1063.                  help=None):
  1064.         super(_CountAction, self).__init__(
  1065.             option_strings=option_strings,
  1066.             dest=dest,
  1067.             nargs=0,
  1068.             default=default,
  1069.             required=required,
  1070.             help=help)
  1072.     def __call__(self, parser, namespace, values, option_string=None):
  1073.         count = getattr(namespace, self.dest, None)
  1074.         if count is None:
  1075.             count = 0
  1076.         setattr(namespace, self.dest, count + 1)
  1079. class _HelpAction(Action):
  1081.     def __init__(self,
  1082.                  option_strings,
  1083.                  dest=SUPPRESS,
  1084.                  default=SUPPRESS,
  1085.                  help=None):
  1086.         super(_HelpAction, self).__init__(
  1087.             option_strings=option_strings,
  1088.             dest=dest,
  1089.             default=default,
  1090.             nargs=0,
  1091.             help=help)
  1093.     def __call__(self, parser, namespace, values, option_string=None):
  1094.         parser.print_help()
  1095.         parser.exit()
  1098. class _VersionAction(Action):
  1100.     def __init__(self,
  1101.                  option_strings,
  1102.                  version=None,
  1103.                  dest=SUPPRESS,
  1104.                  default=SUPPRESS,
  1105.                  help="show program's version number and exit"):
  1106.         super(_VersionAction, self).__init__(
  1107.             option_strings=option_strings,
  1108.             dest=dest,
  1109.             default=default,
  1110.             nargs=0,
  1111.             help=help)
  1112.         self.version = version
  1114.     def __call__(self, parser, namespace, values, option_string=None):
  1115.         version = self.version
  1116.         if version is None:
  1117.             version = parser.version
  1118.         formatter = parser._get_formatter()
  1119.         formatter.add_text(version)
  1120.         parser._print_message(formatter.format_help(), _sys.stdout)
  1121.         parser.exit()
  1124. class _SubParsersAction(Action):
  1126.     class _ChoicesPseudoAction(Action):
  1128.         def __init__(self, name, aliases, help):
  1129.             metavar = dest = name
  1130.             if aliases:
  1131.                 metavar += ' (%s)' % ', '.join(aliases)
  1132.             sup = super(_SubParsersAction._ChoicesPseudoAction, self)
  1133.             sup.__init__(option_strings=[], dest=dest, help=help,
  1134.                          metavar=metavar)
  1136.     def __init__(self,
  1137.                  option_strings,
  1138.                  prog,
  1139.                  parser_class,
  1140.                  dest=SUPPRESS,
  1141.                  required=False,
  1142.                  help=None,
  1143.                  metavar=None):
  1145.         self._prog_prefix = prog
  1146.         self._parser_class = parser_class
  1147.         self._name_parser_map = {}
  1148.         self._choices_actions = []
  1150.         super(_SubParsersAction, self).__init__(
  1151.             option_strings=option_strings,
  1152.             dest=dest,
  1153.             nargs=PARSER,
  1154.             choices=self._name_parser_map,
  1155.             required=required,
  1156.             help=help,
  1157.             metavar=metavar)
  1159.     def add_parser(self, name, **kwargs):
  1160.         # set prog from the existing prefix
  1161.         if kwargs.get('prog') is None:
  1162.             kwargs['prog'] = '%s %s' % (self._prog_prefix, name)
  1164.         aliases = kwargs.pop('aliases', ())
  1166.         # create a pseudo-action to hold the choice help
  1167.         if 'help' in kwargs:
  1168.             help = kwargs.pop('help')
  1169.             choice_action = self._ChoicesPseudoAction(name, aliases, help)
  1170.             self._choices_actions.append(choice_action)
  1172.         # create the parser and add it to the map
  1173.         parser = self._parser_class(**kwargs)
  1174.         self._name_parser_map[name] = parser
  1176.         # make parser available under aliases also
  1177.         for alias in aliases:
  1178.             self._name_parser_map[alias] = parser
  1180.         return parser
  1182.     def _get_subactions(self):
  1183.         return self._choices_actions
  1185.     def __call__(self, parser, namespace, values, option_string=None):
  1186.         parser_name = values[0]
  1187.         arg_strings = values[1:]
  1189.         # set the parser name if requested
  1190.         if self.dest is not SUPPRESS:
  1191.             setattr(namespace, self.dest, parser_name)
  1193.         # select the parser
  1194.         try:
  1195.             parser = self._name_parser_map[parser_name]
  1196.         except KeyError:
  1197.             args = {'parser_name': parser_name,
  1198.                     'choices': ', '.join(self._name_parser_map)}
  1199.             msg = _('unknown parser %(parser_name)r (choices: %(choices)s)') % args
  1200.             raise ArgumentError(self, msg)
  1202.         # parse all the remaining options into the namespace
  1203.         # store any unrecognized options on the object, so that the top
  1204.         # level parser can decide what to do with them
  1206.         # In case this subparser defines new defaults, we parse them
  1207.         # in a new namespace object and then update the original
  1208.         # namespace for the relevant parts.
  1209.         subnamespace, arg_strings = parser.parse_known_args(arg_strings, None)
  1210.         for key, value in vars(subnamespace).items():
  1211.             setattr(namespace, key, value)
  1213.         if arg_strings:
  1214.             vars(namespace).setdefault(_UNRECOGNIZED_ARGS_ATTR, [])
  1215.             getattr(namespace, _UNRECOGNIZED_ARGS_ATTR).extend(arg_strings)
  1217. class _ExtendAction(_AppendAction):
  1218.     def __call__(self, parser, namespace, values, option_string=None):
  1219.         items = getattr(namespace, self.dest, None)
  1220.         items = _copy_items(items)
  1221.         items.extend(values)
  1222.         setattr(namespace, self.dest, items)
  1224. # ==============
  1225. # Type classes
  1226. # ==============
  1228. class FileType(object):
  1229.     """Factory for creating file object types
  1231.     Instances of FileType are typically passed as type= arguments to the
  1232.     ArgumentParser add_argument() method.
  1234.     Keyword Arguments:
  1235.         - mode -- A string indicating how the file is to be opened. Accepts the
  1236.             same values as the builtin open() function.
  1237.         - bufsize -- The file's desired buffer size. Accepts the same values as
  1238.             the builtin open() function.
  1239.         - encoding -- The file's encoding. Accepts the same values as the
  1240.             builtin open() function.
  1241.         - errors -- A string indicating how encoding and decoding errors are to
  1242.             be handled. Accepts the same value as the builtin open() function.
  1243.     """
  1245.     def __init__(self, mode='r', bufsize=-1, encoding=None, errors=None):
  1246.         self._mode = mode
  1247.         self._bufsize = bufsize
  1248.         self._encoding = encoding
  1249.         self._errors = errors
  1251.     def __call__(self, string):
  1252.         # the special argument "-" means sys.std{in,out}
  1253.         if string == '-':
  1254.             if 'r' in self._mode:
  1255.                 return _sys.stdin
  1256.             elif 'w' in self._mode:
  1257.                 return _sys.stdout
  1258.             else:
  1259.                 msg = _('argument "-" with mode %r') % self._mode
  1260.                 raise ValueError(msg)
  1262.         # all other arguments are used as file names
  1263.         try:
  1264.             return open(string, self._mode, self._bufsize, self._encoding,
  1265.                         self._errors)
  1266.         except OSError as e:
  1267.             args = {'filename': string, 'error': e}
  1268.             message = _("can't open '%(filename)s': %(error)s")
  1269.             raise ArgumentTypeError(message % args)
  1271.     def __repr__(self):
  1272.         args = self._mode, self._bufsize
  1273.         kwargs = [('encoding', self._encoding), ('errors', self._errors)]
  1274.         args_str = ', '.join([repr(arg) for arg in args if arg != -1] +
  1275.                              ['%s=%r' % (kw, arg) for kw, arg in kwargs
  1276.                               if arg is not None])
  1277.         return '%s(%s)' % (type(self).__name__, args_str)
  1279. # ===========================
  1280. # Optional and Positional Parsing
  1281. # ===========================
  1283. class Namespace(_AttributeHolder):
  1284.     """Simple object for storing attributes.
  1286.     Implements equality by attribute names and values, and provides a simple
  1287.     string representation.
  1288.     """
  1290.     def __init__(self, **kwargs):
  1291.         for name in kwargs:
  1292.             setattr(self, name, kwargs[name])
  1294.     def __eq__(self, other):
  1295.         if not isinstance(other, Namespace):
  1296.             return NotImplemented
  1297.         return vars(self) == vars(other)
  1299.     def __contains__(self, key):
  1300.         return key in self.__dict__
  1303. class _ActionsContainer(object):
  1305.     def __init__(self,
  1306.                  description,
  1307.                  prefix_chars,
  1308.                  argument_default,
  1309.                  conflict_handler):
  1310.         super(_ActionsContainer, self).__init__()
  1312.         self.description = description
  1313.         self.argument_default = argument_default
  1314.         self.prefix_chars = prefix_chars
  1315.         self.conflict_handler = conflict_handler
  1317.         # set up registries
  1318.         self._registries = {}
  1320.         # register actions
  1321.         self.register('action', None, _StoreAction)
  1322.         self.register('action', 'store', _StoreAction)
  1323.         self.register('action', 'store_const', _StoreConstAction)
  1324.         self.register('action', 'store_true', _StoreTrueAction)
  1325.         self.register('action', 'store_false', _StoreFalseAction)
  1326.         self.register('action', 'append', _AppendAction)
  1327.         self.register('action', 'append_const', _AppendConstAction)
  1328.         self.register('action', 'count', _CountAction)
  1329.         self.register('action', 'help', _HelpAction)
  1330.         self.register('action', 'version', _VersionAction)
  1331.         self.register('action', 'parsers', _SubParsersAction)
  1332.         self.register('action', 'extend', _ExtendAction)
  1334.         # raise an exception if the conflict handler is invalid
  1335.         self._get_handler()
  1337.         # action storage
  1338.         self._actions = []
  1339.         self._option_string_actions = {}
  1341.         # groups
  1342.         self._action_groups = []
  1343.         self._mutually_exclusive_groups = []
  1345.         # defaults storage
  1346.         self._defaults = {}
  1348.         # determines whether an "option" looks like a negative number
  1349.         self._negative_number_matcher = _re.compile(r'^-\d+$|^-\d*\.\d+$')
  1351.         # whether or not there are any optionals that look like negative
  1352.         # numbers -- uses a list so it can be shared and edited
  1353.         self._has_negative_number_optionals = []
  1355.     # ====================
  1356.     # Registration methods
  1357.     # ====================
  1358.     def register(self, registry_name, value, object):
  1359.         registry = self._registries.setdefault(registry_name, {})
  1360.         registry[value] = object
  1362.     def _registry_get(self, registry_name, value, default=None):
  1363.         return self._registries[registry_name].get(value, default)
  1365.     # ==================================
  1366.     # Namespace default accessor methods
  1367.     # ==================================
  1368.     def set_defaults(self, **kwargs):
  1369.         self._defaults.update(kwargs)
  1371.         # if these defaults match any existing arguments, replace
  1372.         # the previous default on the object with the new one
  1373.         for action in self._actions:
  1374.             if action.dest in kwargs:
  1375.                 action.default = kwargs[action.dest]
  1377.     def get_default(self, dest):
  1378.         for action in self._actions:
  1379.             if action.dest == dest and action.default is not None:
  1380.                 return action.default
  1381.         return self._defaults.get(dest, None)
  1384.     # =======================
  1385.     # Adding argument actions
  1386.     # =======================
  1387.     def add_argument(self, *args, **kwargs):
  1388.         """
  1389.         add_argument(dest, ..., name=value, ...)
  1390.         add_argument(option_string, option_string, ..., name=value, ...)
  1391.         """
  1393.         # if no positional args are supplied or only one is supplied and
  1394.         # it doesn't look like an option string, parse a positional
  1395.         # argument
  1396.         chars = self.prefix_chars
  1397.         if not args or len(args) == 1 and args[0][0] not in chars:
  1398.             if args and 'dest' in kwargs:
  1399.                 raise ValueError('dest supplied twice for positional argument')
  1400.             kwargs = self._get_positional_kwargs(*args, **kwargs)
  1402.         # otherwise, we're adding an optional argument
  1403.         else:
  1404.             kwargs = self._get_optional_kwargs(*args, **kwargs)
  1406.         # if no default was supplied, use the parser-level default
  1407.         if 'default' not in kwargs:
  1408.             dest = kwargs['dest']
  1409.             if dest in self._defaults:
  1410.                 kwargs['default'] = self._defaults[dest]
  1411.             elif self.argument_default is not None:
  1412.                 kwargs['default'] = self.argument_default
  1414.         # create the action object, and add it to the parser
  1415.         action_class = self._pop_action_class(kwargs)
  1416.         if not callable(action_class):
  1417.             raise ValueError('unknown action "%s"' % (action_class,))
  1418.         action = action_class(**kwargs)
  1420.         # raise an error if the action type is not callable
  1421.         type_func = self._registry_get('type', action.type, action.type)
  1422.         if not callable(type_func):
  1423.             raise ValueError('%r is not callable' % (type_func,))
  1425.         if type_func is FileType:
  1426.             raise ValueError('%r is a FileType class object, instance of it'
  1427.                              ' must be passed' % (type_func,))
  1429.         # raise an error if the metavar does not match the type
  1430.         if hasattr(self, "_get_formatter"):
  1431.             try:
  1432.                 self._get_formatter()._format_args(action, None)
  1433.             except TypeError:
  1434.                 raise ValueError("length of metavar tuple does not match nargs")
  1436.         return self._add_action(action)
  1438.     def add_argument_group(self, *args, **kwargs):
  1439.         group = _ArgumentGroup(self, *args, **kwargs)
  1440.         self._action_groups.append(group)
  1441.         return group
  1443.     def add_mutually_exclusive_group(self, **kwargs):
  1444.         group = _MutuallyExclusiveGroup(self, **kwargs)
  1445.         self._mutually_exclusive_groups.append(group)
  1446.         return group
  1448.     def _add_action(self, action):
  1449.         # resolve any conflicts
  1450.         self._check_conflict(action)
  1452.         # add to actions list
  1453.         self._actions.append(action)
  1454.         action.container = self
  1456.         # index the action by any option strings it has
  1457.         for option_string in action.option_strings:
  1458.             self._option_string_actions[option_string] = action
  1460.         # set the flag if any option strings look like negative numbers
  1461.         for option_string in action.option_strings:
  1462.             if self._negative_number_matcher.match(option_string):
  1463.                 if not self._has_negative_number_optionals:
  1464.                     self._has_negative_number_optionals.append(True)
  1466.         # return the created action
  1467.         return action
  1469.     def _remove_action(self, action):
  1470.         self._actions.remove(action)
  1472.     def _add_container_actions(self, container):
  1473.         # collect groups by titles
  1474.         title_group_map = {}
  1475.         for group in self._action_groups:
  1476.             if group.title in title_group_map:
  1477.                 msg = _('cannot merge actions - two groups are named %r')
  1478.                 raise ValueError(msg % (group.title))
  1479.             title_group_map[group.title] = group
  1481.         # map each action to its group
  1482.         group_map = {}
  1483.         for group in container._action_groups:
  1485.             # if a group with the title exists, use that, otherwise
  1486.             # create a new group matching the container's group
  1487.             if group.title not in title_group_map:
  1488.                 title_group_map[group.title] = self.add_argument_group(
  1489.                     title=group.title,
  1490.                     description=group.description,
  1491.                     conflict_handler=group.conflict_handler)
  1493.             # map the actions to their new group
  1494.             for action in group._group_actions:
  1495.                 group_map[action] = title_group_map[group.title]
  1497.         # add container's mutually exclusive groups
  1498.         # NOTE: if add_mutually_exclusive_group ever gains title= and
  1499.         # description= then this code will need to be expanded as above
  1500.         for group in container._mutually_exclusive_groups:
  1501.             mutex_group = self.add_mutually_exclusive_group(
  1502.                 required=group.required)
  1504.             # map the actions to their new mutex group
  1505.             for action in group._group_actions:
  1506.                 group_map[action] = mutex_group
  1508.         # add all actions to this container or their group
  1509.         for action in container._actions:
  1510.             group_map.get(action, self)._add_action(action)
  1512.     def _get_positional_kwargs(self, dest, **kwargs):
  1513.         # make sure required is not specified
  1514.         if 'required' in kwargs:
  1515.             msg = _("'required' is an invalid argument for positionals")
  1516.             raise TypeError(msg)
  1518.         # mark positional arguments as required if at least one is
  1519.         # always required
  1520.         if kwargs.get('nargs') not in [OPTIONAL, ZERO_OR_MORE]:
  1521.             kwargs['required'] = True
  1522.         if kwargs.get('nargs') == ZERO_OR_MORE and 'default' not in kwargs:
  1523.             kwargs['required'] = True
  1525.         # return the keyword arguments with no option strings
  1526.         return dict(kwargs, dest=dest, option_strings=[])
  1528.     def _get_optional_kwargs(self, *args, **kwargs):
  1529.         # determine short and long option strings
  1530.         option_strings = []
  1531.         long_option_strings = []
  1532.         for option_string in args:
  1533.             # error on strings that don't start with an appropriate prefix
  1534.             if not option_string[0] in self.prefix_chars:
  1535.                 args = {'option': option_string,
  1536.                         'prefix_chars': self.prefix_chars}
  1537.                 msg = _('invalid option string %(option)r: '
  1538.                         'must start with a character %(prefix_chars)r')
  1539.                 raise ValueError(msg % args)
  1541.             # strings starting with two prefix characters are long options
  1542.             option_strings.append(option_string)
  1543.             if len(option_string) > 1 and option_string[1] in self.prefix_chars:
  1544.                 long_option_strings.append(option_string)
  1546.         # infer destination, '--foo-bar' -> 'foo_bar' and '-x' -> 'x'
  1547.         dest = kwargs.pop('dest', None)
  1548.         if dest is None:
  1549.             if long_option_strings:
  1550.                 dest_option_string = long_option_strings[0]
  1551.             else:
  1552.                 dest_option_string = option_strings[0]
  1553.             dest = dest_option_string.lstrip(self.prefix_chars)
  1554.             if not dest:
  1555.                 msg = _('dest= is required for options like %r')
  1556.                 raise ValueError(msg % option_string)
  1557.             dest = dest.replace('-', '_')
  1559.         # return the updated keyword arguments
  1560.         return dict(kwargs, dest=dest, option_strings=option_strings)
  1562.     def _pop_action_class(self, kwargs, default=None):
  1563.         action = kwargs.pop('action', default)
  1564.         return self._registry_get('action', action, action)
  1566.     def _get_handler(self):
  1567.         # determine function from conflict handler string
  1568.         handler_func_name = '_handle_conflict_%s' % self.conflict_handler
  1569.         try:
  1570.             return getattr(self, handler_func_name)
  1571.         except AttributeError:
  1572.             msg = _('invalid conflict_resolution value: %r')
  1573.             raise ValueError(msg % self.conflict_handler)
  1575.     def _check_conflict(self, action):
  1577.         # find all options that conflict with this option
  1578.         confl_optionals = []
  1579.         for option_string in action.option_strings:
  1580.             if option_string in self._option_string_actions:
  1581.                 confl_optional = self._option_string_actions[option_string]
  1582.                 confl_optionals.append((option_string, confl_optional))
  1584.         # resolve any conflicts
  1585.         if confl_optionals:
  1586.             conflict_handler = self._get_handler()
  1587.             conflict_handler(action, confl_optionals)
  1589.     def _handle_conflict_error(self, action, conflicting_actions):
  1590.         message = ngettext('conflicting option string: %s',
  1591.                            'conflicting option strings: %s',
  1592.                            len(conflicting_actions))
  1593.         conflict_string = ', '.join([option_string
  1594.                                      for option_string, action
  1595.                                      in conflicting_actions])
  1596.         raise ArgumentError(action, message % conflict_string)
  1598.     def _handle_conflict_resolve(self, action, conflicting_actions):
  1600.         # remove all conflicting options
  1601.         for option_string, action in conflicting_actions:
  1603.             # remove the conflicting option
  1604.             action.option_strings.remove(option_string)
  1605.             self._option_string_actions.pop(option_string, None)
  1607.             # if the option now has no option string, remove it from the
  1608.             # container holding it
  1609.             if not action.option_strings:
  1610.                 action.container._remove_action(action)
  1613. class _ArgumentGroup(_ActionsContainer):
  1615.     def __init__(self, container, title=None, description=None, **kwargs):
  1616.         # add any missing keyword arguments by checking the container
  1617.         update = kwargs.setdefault
  1618.         update('conflict_handler', container.conflict_handler)
  1619.         update('prefix_chars', container.prefix_chars)
  1620.         update('argument_default', container.argument_default)
  1621.         super_init = super(_ArgumentGroup, self).__init__
  1622.         super_init(description=description, **kwargs)
  1624.         # group attributes
  1625.         self.title = title
  1626.         self._group_actions = []
  1628.         # share most attributes with the container
  1629.         self._registries = container._registries
  1630.         self._actions = container._actions
  1631.         self._option_string_actions = container._option_string_actions
  1632.         self._defaults = container._defaults
  1633.         self._has_negative_number_optionals = \
  1634.             container._has_negative_number_optionals
  1635.         self._mutually_exclusive_groups = container._mutually_exclusive_groups
  1637.     def _add_action(self, action):
  1638.         action = super(_ArgumentGroup, self)._add_action(action)
  1639.         self._group_actions.append(action)
  1640.         return action
  1642.     def _remove_action(self, action):
  1643.         super(_ArgumentGroup, self)._remove_action(action)
  1644.         self._group_actions.remove(action)
  1647. class _MutuallyExclusiveGroup(_ArgumentGroup):
  1649.     def __init__(self, container, required=False):
  1650.         super(_MutuallyExclusiveGroup, self).__init__(container)
  1651.         self.required = required
  1652.         self._container = container
  1654.     def _add_action(self, action):
  1655.         if action.required:
  1656.             msg = _('mutually exclusive arguments must be optional')
  1657.             raise ValueError(msg)
  1658.         action = self._container._add_action(action)
  1659.         self._group_actions.append(action)
  1660.         return action
  1662.     def _remove_action(self, action):
  1663.         self._container._remove_action(action)
  1664.         self._group_actions.remove(action)
  1667. class ArgumentParser(_AttributeHolder, _ActionsContainer):
  1668.     """Object for parsing command line strings into Python objects.
  1670.     Keyword Arguments:
  1671.         - prog -- The name of the program (default: sys.argv[0])
  1672.         - usage -- A usage message (default: auto-generated from arguments)
  1673.         - description -- A description of what the program does
  1674.         - epilog -- Text following the argument descriptions
  1675.         - parents -- Parsers whose arguments should be copied into this one
  1676.         - formatter_class -- HelpFormatter class for printing help messages
  1677.         - prefix_chars -- Characters that prefix optional arguments
  1678.         - fromfile_prefix_chars -- Characters that prefix files containing
  1679.             additional arguments
  1680.         - argument_default -- The default value for all arguments
  1681.         - conflict_handler -- String indicating how to handle conflicts
  1682.         - add_help -- Add a -h/-help option
  1683.         - allow_abbrev -- Allow long options to be abbreviated unambiguously
  1684.         - exit_on_error -- Determines whether or not ArgumentParser exits with
  1685.             error info when an error occurs
  1686.     """
  1688.     def __init__(self,
  1689.                  prog=None,
  1690.                  usage=None,
  1691.                  description=None,
  1692.                  epilog=None,
  1693.                  parents=[],
  1694.                  formatter_class=HelpFormatter,
  1695.                  prefix_chars='-',
  1696.                  fromfile_prefix_chars=None,
  1697.                  argument_default=None,
  1698.                  conflict_handler='error',
  1699.                  add_help=True,
  1700.                  allow_abbrev=True,
  1701.                  exit_on_error=True):
  1703.         superinit = super(ArgumentParser, self).__init__
  1704.         superinit(description=description,
  1705.                   prefix_chars=prefix_chars,
  1706.                   argument_default=argument_default,
  1707.                   conflict_handler=conflict_handler)
  1709.         # default setting for prog
  1710.         if prog is None:
  1711.             prog = _os.path.basename(_sys.argv[0])
  1713.         self.prog = prog
  1714.         self.usage = usage
  1715.         self.epilog = epilog
  1716.         self.formatter_class = formatter_class
  1717.         self.fromfile_prefix_chars = fromfile_prefix_chars
  1718.         self.add_help = add_help
  1719.         self.allow_abbrev = allow_abbrev
  1720.         self.exit_on_error = exit_on_error
  1722.         add_group = self.add_argument_group
  1723.         self._positionals = add_group(_('positional arguments'))
  1724.         self._optionals = add_group(_('options'))
  1725.         self._subparsers = None
  1727.         # register types
  1728.         def identity(string):
  1729.             return string
  1730.         self.register('type', None, identity)
  1732.         # add help argument if necessary
  1733.         # (using explicit default to override global argument_default)
  1734.         default_prefix = '-' if '-' in prefix_chars else prefix_chars[0]
  1735.         if self.add_help:
  1736.             self.add_argument(
  1737.                 default_prefix+'h', default_prefix*2+'help',
  1738.                 action='help', default=SUPPRESS,
  1739.                 help=_('show this help message and exit'))
  1741.         # add parent arguments and defaults
  1742.         for parent in parents:
  1743.             self._add_container_actions(parent)
  1744.             try:
  1745.                 defaults = parent._defaults
  1746.             except AttributeError:
  1747.                 pass
  1748.             else:
  1749.                 self._defaults.update(defaults)
  1751.     # =======================
  1752.     # Pretty __repr__ methods
  1753.     # =======================
  1754.     def _get_kwargs(self):
  1755.         names = [
  1756.             'prog',
  1757.             'usage',
  1758.             'description',
  1759.             'formatter_class',
  1760.             'conflict_handler',
  1761.             'add_help',
  1762.         ]
  1763.         return [(name, getattr(self, name)) for name in names]
  1765.     # ==================================
  1766.     # Optional/Positional adding methods
  1767.     # ==================================
  1768.     def add_subparsers(self, **kwargs):
  1769.         if self._subparsers is not None:
  1770.             self.error(_('cannot have multiple subparser arguments'))
  1772.         # add the parser class to the arguments if it's not present
  1773.         kwargs.setdefault('parser_class', type(self))
  1775.         if 'title' in kwargs or 'description' in kwargs:
  1776.             title = _(kwargs.pop('title', 'subcommands'))
  1777.             description = _(kwargs.pop('description', None))
  1778.             self._subparsers = self.add_argument_group(title, description)
  1779.         else:
  1780.             self._subparsers = self._positionals
  1782.         # prog defaults to the usage message of this parser, skipping
  1783.         # optional arguments and with no "usage:" prefix
  1784.         if kwargs.get('prog') is None:
  1785.             formatter = self._get_formatter()
  1786.             positionals = self._get_positional_actions()
  1787.             groups = self._mutually_exclusive_groups
  1788.             formatter.add_usage(self.usage, positionals, groups, '')
  1789.             kwargs['prog'] = formatter.format_help().strip()
  1791.         # create the parsers action and add it to the positionals list
  1792.         parsers_class = self._pop_action_class(kwargs, 'parsers')
  1793.         action = parsers_class(option_strings=[], **kwargs)
  1794.         self._subparsers._add_action(action)
  1796.         # return the created parsers action
  1797.         return action
  1799.     def _add_action(self, action):
  1800.         if action.option_strings:
  1801.             self._optionals._add_action(action)
  1802.         else:
  1803.             self._positionals._add_action(action)
  1804.         return action
  1806.     def _get_optional_actions(self):
  1807.         return [action
  1808.                 for action in self._actions
  1809.                 if action.option_strings]
  1811.     def _get_positional_actions(self):
  1812.         return [action
  1813.                 for action in self._actions
  1814.                 if not action.option_strings]
  1816.     # =====================================
  1817.     # Command line argument parsing methods
  1818.     # =====================================
  1819.     def parse_args(self, args=None, namespace=None):
  1820.         args, argv = self.parse_known_args(args, namespace)
  1821.         if argv:
  1822.             msg = _('unrecognized arguments: %s')
  1823.             self.error(msg % ' '.join(argv))
  1824.         return args
  1826.     def parse_known_args(self, args=None, namespace=None):
  1827.         if args is None:
  1828.             # args default to the system args
  1829.             args = _sys.argv[1:]
  1830.         else:
  1831.             # make sure that args are mutable
  1832.             args = list(args)
  1834.         # default Namespace built from parser defaults
  1835.         if namespace is None:
  1836.             namespace = Namespace()
  1838.         # add any action defaults that aren't present
  1839.         for action in self._actions:
  1840.             if action.dest is not SUPPRESS:
  1841.                 if not hasattr(namespace, action.dest):
  1842.                     if action.default is not SUPPRESS:
  1843.                         setattr(namespace, action.dest, action.default)
  1845.         # add any parser defaults that aren't present
  1846.         for dest in self._defaults:
  1847.             if not hasattr(namespace, dest):
  1848.                 setattr(namespace, dest, self._defaults[dest])
  1850.         # parse the arguments and exit if there are any errors
  1851.         if self.exit_on_error:
  1852.             try:
  1853.                 namespace, args = self._parse_known_args(args, namespace)
  1854.             except ArgumentError:
  1855.                 err = _sys.exc_info()[1]
  1856.                 self.error(str(err))
  1857.         else:
  1858.             namespace, args = self._parse_known_args(args, namespace)
  1860.         if hasattr(namespace, _UNRECOGNIZED_ARGS_ATTR):
  1861.             args.extend(getattr(namespace, _UNRECOGNIZED_ARGS_ATTR))
  1862.             delattr(namespace, _UNRECOGNIZED_ARGS_ATTR)
  1863.         return namespace, args
  1865.     def _parse_known_args(self, arg_strings, namespace):
  1866.         # replace arg strings that are file references
  1867.         if self.fromfile_prefix_chars is not None:
  1868.             arg_strings = self._read_args_from_files(arg_strings)
  1870.         # map all mutually exclusive arguments to the other arguments
  1871.         # they can't occur with
  1872.         action_conflicts = {}
  1873.         for mutex_group in self._mutually_exclusive_groups:
  1874.             group_actions = mutex_group._group_actions
  1875.             for i, mutex_action in enumerate(mutex_group._group_actions):
  1876.                 conflicts = action_conflicts.setdefault(mutex_action, [])
  1877.                 conflicts.extend(group_actions[:i])
  1878.                 conflicts.extend(group_actions[i + 1:])
  1880.         # find all option indices, and determine the arg_string_pattern
  1881.         # which has an 'O' if there is an option at an index,
  1882.         # an 'A' if there is an argument, or a '-' if there is a '--'
  1883.         option_string_indices = {}
  1884.         arg_string_pattern_parts = []
  1885.         arg_strings_iter = iter(arg_strings)
  1886.         for i, arg_string in enumerate(arg_strings_iter):
  1888.             # all args after -- are non-options
  1889.             if arg_string == '--':
  1890.                 arg_string_pattern_parts.append('-')
  1891.                 for arg_string in arg_strings_iter:
  1892.                     arg_string_pattern_parts.append('A')
  1894.             # otherwise, add the arg to the arg strings
  1895.             # and note the index if it was an option
  1896.             else:
  1897.                 option_tuple = self._parse_optional(arg_string)
  1898.                 if option_tuple is None:
  1899.                     pattern = 'A'
  1900.                 else:
  1901.                     option_string_indices[i] = option_tuple
  1902.                     pattern = 'O'
  1903.                 arg_string_pattern_parts.append(pattern)
  1905.         # join the pieces together to form the pattern
  1906.         arg_strings_pattern = ''.join(arg_string_pattern_parts)
  1908.         # converts arg strings to the appropriate and then takes the action
  1909.         seen_actions = set()
  1910.         seen_non_default_actions = set()
  1912.         def take_action(action, argument_strings, option_string=None):
  1913.             seen_actions.add(action)
  1914.             argument_values = self._get_values(action, argument_strings)
  1916.             # error if this argument is not allowed with other previously
  1917.             # seen arguments, assuming that actions that use the default
  1918.             # value don't really count as "present"
  1919.             if argument_values is not action.default:
  1920.                 seen_non_default_actions.add(action)
  1921.                 for conflict_action in action_conflicts.get(action, []):
  1922.                     if conflict_action in seen_non_default_actions:
  1923.                         msg = _('not allowed with argument %s')
  1924.                         action_name = _get_action_name(conflict_action)
  1925.                         raise ArgumentError(action, msg % action_name)
  1927.             # take the action if we didn't receive a SUPPRESS value
  1928.             # (e.g. from a default)
  1929.             if argument_values is not SUPPRESS:
  1930.                 action(self, namespace, argument_values, option_string)
  1932.         # function to convert arg_strings into an optional action
  1933.         def consume_optional(start_index):
  1935.             # get the optional identified at this index
  1936.             option_tuple = option_string_indices[start_index]
  1937.             action, option_string, explicit_arg = option_tuple
  1939.             # identify additional optionals in the same arg string
  1940.             # (e.g. -xyz is the same as -x -y -z if no args are required)
  1941.             match_argument = self._match_argument
  1942.             action_tuples = []
  1943.             while True:
  1945.                 # if we found no optional action, skip it
  1946.                 if action is None:
  1947.                     extras.append(arg_strings[start_index])
  1948.                     return start_index + 1
  1950.                 # if there is an explicit argument, try to match the
  1951.                 # optional's string arguments to only this
  1952.                 if explicit_arg is not None:
  1953.                     arg_count = match_argument(action, 'A')
  1955.                     # if the action is a single-dash option and takes no
  1956.                     # arguments, try to parse more single-dash options out
  1957.                     # of the tail of the option string
  1958.                     chars = self.prefix_chars
  1959.                     if arg_count == 0 and option_string[1] not in chars:
  1960.                         action_tuples.append((action, [], option_string))
  1961.                         char = option_string[0]
  1962.                         option_string = char + explicit_arg[0]
  1963.                         new_explicit_arg = explicit_arg[1:] or None
  1964.                         optionals_map = self._option_string_actions
  1965.                         if option_string in optionals_map:
  1966.                             action = optionals_map[option_string]
  1967.                             explicit_arg = new_explicit_arg
  1968.                         else:
  1969.                             msg = _('ignored explicit argument %r')
  1970.                             raise ArgumentError(action, msg % explicit_arg)
  1972.                     # if the action expect exactly one argument, we've
  1973.                     # successfully matched the option; exit the loop
  1974.                     elif arg_count == 1:
  1975.                         stop = start_index + 1
  1976.                         args = [explicit_arg]
  1977.                         action_tuples.append((action, args, option_string))
  1978.                         break
  1980.                     # error if a double-dash option did not use the
  1981.                     # explicit argument
  1982.                     else:
  1983.                         msg = _('ignored explicit argument %r')
  1984.                         raise ArgumentError(action, msg % explicit_arg)
  1986.                 # if there is no explicit argument, try to match the
  1987.                 # optional's string arguments with the following strings
  1988.                 # if successful, exit the loop
  1989.                 else:
  1990.                     start = start_index + 1
  1991.                     selected_patterns = arg_strings_pattern[start:]
  1992.                     arg_count = match_argument(action, selected_patterns)
  1993.                     stop = start + arg_count
  1994.                     args = arg_strings[start:stop]
  1995.                     action_tuples.append((action, args, option_string))
  1996.                     break
  1998.             # add the Optional to the list and return the index at which
  1999.             # the Optional's string args stopped
  2000.             assert action_tuples
  2001.             for action, args, option_string in action_tuples:
  2002.                 take_action(action, args, option_string)
  2003.             return stop
  2005.         # the list of Positionals left to be parsed; this is modified
  2006.         # by consume_positionals()
  2007.         positionals = self._get_positional_actions()
  2009.         # function to convert arg_strings into positional actions
  2010.         def consume_positionals(start_index):
  2011.             # match as many Positionals as possible
  2012.             match_partial = self._match_arguments_partial
  2013.             selected_pattern = arg_strings_pattern[start_index:]
  2014.             arg_counts = match_partial(positionals, selected_pattern)
  2016.             # slice off the appropriate arg strings for each Positional
  2017.             # and add the Positional and its args to the list
  2018.             for action, arg_count in zip(positionals, arg_counts):
  2019.                 args = arg_strings[start_index: start_index + arg_count]
  2020.                 start_index += arg_count
  2021.                 take_action(action, args)
  2023.             # slice off the Positionals that we just parsed and return the
  2024.             # index at which the Positionals' string args stopped
  2025.             positionals[:] = positionals[len(arg_counts):]
  2026.             return start_index
  2028.         # consume Positionals and Optionals alternately, until we have
  2029.         # passed the last option string
  2030.         extras = []
  2031.         start_index = 0
  2032.         if option_string_indices:
  2033.             max_option_string_index = max(option_string_indices)
  2034.         else:
  2035.             max_option_string_index = -1
  2036.         while start_index <= max_option_string_index:
  2038.             # consume any Positionals preceding the next option
  2039.             next_option_string_index = min([
  2040.                 index
  2041.                 for index in option_string_indices
  2042.                 if index >= start_index])
  2043.             if start_index != next_option_string_index:
  2044.                 positionals_end_index = consume_positionals(start_index)
  2046.                 # only try to parse the next optional if we didn't consume
  2047.                 # the option string during the positionals parsing
  2048.                 if positionals_end_index > start_index:
  2049.                     start_index = positionals_end_index
  2050.                     continue
  2051.                 else:
  2052.                     start_index = positionals_end_index
  2054.             # if we consumed all the positionals we could and we're not
  2055.             # at the index of an option string, there were extra arguments
  2056.             if start_index not in option_string_indices:
  2057.                 strings = arg_strings[start_index:next_option_string_index]
  2058.                 extras.extend(strings)
  2059.                 start_index = next_option_string_index
  2061.             # consume the next optional and any arguments for it
  2062.             start_index = consume_optional(start_index)
  2064.         # consume any positionals following the last Optional
  2065.         stop_index = consume_positionals(start_index)
  2067.         # if we didn't consume all the argument strings, there were extras
  2068.         extras.extend(arg_strings[stop_index:])
  2070.         # make sure all required actions were present and also convert
  2071.         # action defaults which were not given as arguments
  2072.         required_actions = []
  2073.         for action in self._actions:
  2074.             if action not in seen_actions:
  2075.                 if action.required:
  2076.                     required_actions.append(_get_action_name(action))
  2077.                 else:
  2078.                     # Convert action default now instead of doing it before
  2079.                     # parsing arguments to avoid calling convert functions
  2080.                     # twice (which may fail) if the argument was given, but
  2081.                     # only if it was defined already in the namespace
  2082.                     if (action.default is not None and
  2083.                         isinstance(action.default, str) and
  2084.                         hasattr(namespace, action.dest) and
  2085.                         action.default is getattr(namespace, action.dest)):
  2086.                         setattr(namespace, action.dest,
  2087.                                 self._get_value(action, action.default))
  2089.         if required_actions:
  2090.             self.error(_('the following arguments are required: %s') %
  2091.                        ', '.join(required_actions))
  2093.         # make sure all required groups had one option present
  2094.         for group in self._mutually_exclusive_groups:
  2095.             if group.required:
  2096.                 for action in group._group_actions:
  2097.                     if action in seen_non_default_actions:
  2098.                         break
  2100.                 # if no actions were used, report the error
  2101.                 else:
  2102.                     names = [_get_action_name(action)
  2103.                              for action in group._group_actions
  2104.                              if action.help is not SUPPRESS]
  2105.                     msg = _('one of the arguments %s is required')
  2106.                     self.error(msg % ' '.join(names))
  2108.         # return the updated namespace and the extra arguments
  2109.         return namespace, extras
  2111.     def _read_args_from_files(self, arg_strings):
  2112.         # expand arguments referencing files
  2113.         new_arg_strings = []
  2114.         for arg_string in arg_strings:
  2116.             # for regular arguments, just add them back into the list
  2117.             if not arg_string or arg_string[0] not in self.fromfile_prefix_chars:
  2118.                 new_arg_strings.append(arg_string)
  2120.             # replace arguments referencing files with the file content
  2121.             else:
  2122.                 try:
  2123.                     with open(arg_string[1:]) as args_file:
  2124.                         arg_strings = []
  2125.                         for arg_line in args_file.read().splitlines():
  2126.                             for arg in self.convert_arg_line_to_args(arg_line):
  2127.                                 arg_strings.append(arg)
  2128.                         arg_strings = self._read_args_from_files(arg_strings)
  2129.                         new_arg_strings.extend(arg_strings)
  2130.                 except OSError:
  2131.                     err = _sys.exc_info()[1]
  2132.                     self.error(str(err))
  2134.         # return the modified argument list
  2135.         return new_arg_strings
  2137.     def convert_arg_line_to_args(self, arg_line):
  2138.         return [arg_line]
  2140.     def _match_argument(self, action, arg_strings_pattern):
  2141.         # match the pattern for this action to the arg strings
  2142.         nargs_pattern = self._get_nargs_pattern(action)
  2143.         match = _re.match(nargs_pattern, arg_strings_pattern)
  2145.         # raise an exception if we weren't able to find a match
  2146.         if match is None:
  2147.             nargs_errors = {
  2148.                 None: _('expected one argument'),
  2149.                 OPTIONAL: _('expected at most one argument'),
  2150.                 ONE_OR_MORE: _('expected at least one argument'),
  2151.             }
  2152.             msg = nargs_errors.get(action.nargs)
  2153.             if msg is None:
  2154.                 msg = ngettext('expected %s argument',
  2155.                                'expected %s arguments',
  2156.                                action.nargs) % action.nargs
  2157.             raise ArgumentError(action, msg)
  2159.         # return the number of arguments matched
  2160.         return len(match.group(1))
  2162.     def _match_arguments_partial(self, actions, arg_strings_pattern):
  2163.         # progressively shorten the actions list by slicing off the
  2164.         # final actions until we find a match
  2165.         result = []
  2166.         for i in range(len(actions), 0, -1):
  2167.             actions_slice = actions[:i]
  2168.             pattern = ''.join([self._get_nargs_pattern(action)
  2169.                                for action in actions_slice])
  2170.             match = _re.match(pattern, arg_strings_pattern)
  2171.             if match is not None:
  2172.                 result.extend([len(string) for string in match.groups()])
  2173.                 break
  2175.         # return the list of arg string counts
  2176.         return result
  2178.     def _parse_optional(self, arg_string):
  2179.         # if it's an empty string, it was meant to be a positional
  2180.         if not arg_string:
  2181.             return None
  2183.         # if it doesn't start with a prefix, it was meant to be positional
  2184.         if not arg_string[0] in self.prefix_chars:
  2185.             return None
  2187.         # if the option string is present in the parser, return the action
  2188.         if arg_string in self._option_string_actions:
  2189.             action = self._option_string_actions[arg_string]
  2190.             return action, arg_string, None
  2192.         # if it's just a single character, it was meant to be positional
  2193.         if len(arg_string) == 1:
  2194.             return None
  2196.         # if the option string before the "=" is present, return the action
  2197.         if '=' in arg_string:
  2198.             option_string, explicit_arg = arg_string.split('=', 1)
  2199.             if option_string in self._option_string_actions:
  2200.                 action = self._option_string_actions[option_string]
  2201.                 return action, option_string, explicit_arg
  2203.         # search through all possible prefixes of the option string
  2204.         # and all actions in the parser for possible interpretations
  2205.         option_tuples = self._get_option_tuples(arg_string)
  2207.         # if multiple actions match, the option string was ambiguous
  2208.         if len(option_tuples) > 1:
  2209.             options = ', '.join([option_string
  2210.                 for action, option_string, explicit_arg in option_tuples])
  2211.             args = {'option': arg_string, 'matches': options}
  2212.             msg = _('ambiguous option: %(option)s could match %(matches)s')
  2213.             self.error(msg % args)
  2215.         # if exactly one action matched, this segmentation is good,
  2216.         # so return the parsed action
  2217.         elif len(option_tuples) == 1:
  2218.             option_tuple, = option_tuples
  2219.             return option_tuple
  2221.         # if it was not found as an option, but it looks like a negative
  2222.         # number, it was meant to be positional
  2223.         # unless there are negative-number-like options
  2224.         if self._negative_number_matcher.match(arg_string):
  2225.             if not self._has_negative_number_optionals:
  2226.                 return None
  2228.         # if it contains a space, it was meant to be a positional
  2229.         if ' ' in arg_string:
  2230.             return None
  2232.         # it was meant to be an optional but there is no such option
  2233.         # in this parser (though it might be a valid option in a subparser)
  2234.         return None, arg_string, None
  2236.     def _get_option_tuples(self, option_string):
  2237.         result = []
  2239.         # option strings starting with two prefix characters are only
  2240.         # split at the '='
  2241.         chars = self.prefix_chars
  2242.         if option_string[0] in chars and option_string[1] in chars:
  2243.             if self.allow_abbrev:
  2244.                 if '=' in option_string:
  2245.                     option_prefix, explicit_arg = option_string.split('=', 1)
  2246.                 else:
  2247.                     option_prefix = option_string
  2248.                     explicit_arg = None
  2249.                 for option_string in self._option_string_actions:
  2250.                     if option_string.startswith(option_prefix):
  2251.                         action = self._option_string_actions[option_string]
  2252.                         tup = action, option_string, explicit_arg
  2253.                         result.append(tup)
  2255.         # single character options can be concatenated with their arguments
  2256.         # but multiple character options always have to have their argument
  2257.         # separate
  2258.         elif option_string[0] in chars and option_string[1] not in chars:
  2259.             option_prefix = option_string
  2260.             explicit_arg = None
  2261.             short_option_prefix = option_string[:2]
  2262.             short_explicit_arg = option_string[2:]
  2264.             for option_string in self._option_string_actions:
  2265.                 if option_string == short_option_prefix:
  2266.                     action = self._option_string_actions[option_string]
  2267.                     tup = action, option_string, short_explicit_arg
  2268.                     result.append(tup)
  2269.                 elif option_string.startswith(option_prefix):
  2270.                     action = self._option_string_actions[option_string]
  2271.                     tup = action, option_string, explicit_arg
  2272.                     result.append(tup)
  2274.         # shouldn't ever get here
  2275.         else:
  2276.             self.error(_('unexpected option string: %s') % option_string)
  2278.         # return the collected option tuples
  2279.         return result
  2281.     def _get_nargs_pattern(self, action):
  2282.         # in all examples below, we have to allow for '--' args
  2283.         # which are represented as '-' in the pattern
  2284.         nargs = action.nargs
  2286.         # the default (None) is assumed to be a single argument
  2287.         if nargs is None:
  2288.             nargs_pattern = '(-*A-*)'
  2290.         # allow zero or one arguments
  2291.         elif nargs == OPTIONAL:
  2292.             nargs_pattern = '(-*A?-*)'
  2294.         # allow zero or more arguments
  2295.         elif nargs == ZERO_OR_MORE:
  2296.             nargs_pattern = '(-*[A-]*)'
  2298.         # allow one or more arguments
  2299.         elif nargs == ONE_OR_MORE:
  2300.             nargs_pattern = '(-*A[A-]*)'
  2302.         # allow any number of options or arguments
  2303.         elif nargs == REMAINDER:
  2304.             nargs_pattern = '([-AO]*)'
  2306.         # allow one argument followed by any number of options or arguments
  2307.         elif nargs == PARSER:
  2308.             nargs_pattern = '(-*A[-AO]*)'
  2310.         # suppress action, like nargs=0
  2311.         elif nargs == SUPPRESS:
  2312.             nargs_pattern = '(-*-*)'
  2314.         # all others should be integers
  2315.         else:
  2316.             nargs_pattern = '(-*%s-*)' % '-*'.join('A' * nargs)
  2318.         # if this is an optional action, -- is not allowed
  2319.         if action.option_strings:
  2320.             nargs_pattern = nargs_pattern.replace('-*', '')
  2321.             nargs_pattern = nargs_pattern.replace('-', '')
  2323.         # return the pattern
  2324.         return nargs_pattern
  2326.     # ========================
  2327.     # Alt command line argument parsing, allowing free intermix
  2328.     # ========================
  2330.     def parse_intermixed_args(self, args=None, namespace=None):
  2331.         args, argv = self.parse_known_intermixed_args(args, namespace)
  2332.         if argv:
  2333.             msg = _('unrecognized arguments: %s')
  2334.             self.error(msg % ' '.join(argv))
  2335.         return args
  2337.     def parse_known_intermixed_args(self, args=None, namespace=None):
  2338.         # returns a namespace and list of extras
  2339.         #
  2340.         # positional can be freely intermixed with optionals.  optionals are
  2341.         # first parsed with all positional arguments deactivated.  The 'extras'
  2342.         # are then parsed.  If the parser definition is incompatible with the
  2343.         # intermixed assumptions (e.g. use of REMAINDER, subparsers) a
  2344.         # TypeError is raised.
  2345.         #
  2346.         # positionals are 'deactivated' by setting nargs and default to
  2347.         # SUPPRESS.  This blocks the addition of that positional to the
  2348.         # namespace
  2350.         positionals = self._get_positional_actions()
  2351.         a = [action for action in positionals
  2352.              if action.nargs in [PARSER, REMAINDER]]
  2353.         if a:
  2354.             raise TypeError('parse_intermixed_args: positional arg'
  2355.                             ' with nargs=%s'%a[0].nargs)
  2357.         if [action.dest for group in self._mutually_exclusive_groups
  2358.             for action in group._group_actions if action in positionals]:
  2359.             raise TypeError('parse_intermixed_args: positional in'
  2360.                             ' mutuallyExclusiveGroup')
  2362.         try:
  2363.             save_usage = self.usage
  2364.             try:
  2365.                 if self.usage is None:
  2366.                     # capture the full usage for use in error messages
  2367.                     self.usage = self.format_usage()[7:]
  2368.                 for action in positionals:
  2369.                     # deactivate positionals
  2370.                     action.save_nargs = action.nargs
  2371.                     # action.nargs = 0
  2372.                     action.nargs = SUPPRESS
  2373.                     action.save_default = action.default
  2374.                     action.default = SUPPRESS
  2375.                 namespace, remaining_args = self.parse_known_args(args,
  2376.                                                                   namespace)
  2377.                 for action in positionals:
  2378.                     # remove the empty positional values from namespace
  2379.                     if (hasattr(namespace, action.dest)
  2380.                             and getattr(namespace, action.dest)==[]):
  2381.                         from warnings import warn
  2382.                         warn('Do not expect %s in %s' % (action.dest, namespace))
  2383.                         delattr(namespace, action.dest)
  2384.             finally:
  2385.                 # restore nargs and usage before exiting
  2386.                 for action in positionals:
  2387.                     action.nargs = action.save_nargs
  2388.                     action.default = action.save_default
  2389.             optionals = self._get_optional_actions()
  2390.             try:
  2391.                 # parse positionals.  optionals aren't normally required, but
  2392.                 # they could be, so make sure they aren't.
  2393.                 for action in optionals:
  2394.                     action.save_required = action.required
  2395.                     action.required = False
  2396.                 for group in self._mutually_exclusive_groups:
  2397.                     group.save_required = group.required
  2398.                     group.required = False
  2399.                 namespace, extras = self.parse_known_args(remaining_args,
  2400.                                                           namespace)
  2401.             finally:
  2402.                 # restore parser values before exiting
  2403.                 for action in optionals:
  2404.                     action.required = action.save_required
  2405.                 for group in self._mutually_exclusive_groups:
  2406.                     group.required = group.save_required
  2407.         finally:
  2408.             self.usage = save_usage
  2409.         return namespace, extras
  2411.     # ========================
  2412.     # Value conversion methods
  2413.     # ========================
  2414.     def _get_values(self, action, arg_strings):
  2415.         # for everything but PARSER, REMAINDER args, strip out first '--'
  2416.         if action.nargs not in [PARSER, REMAINDER]:
  2417.             try:
  2418.                 arg_strings.remove('--')
  2419.             except ValueError:
  2420.                 pass
  2422.         # optional argument produces a default when not present
  2423.         if not arg_strings and action.nargs == OPTIONAL:
  2424.             if action.option_strings:
  2425.                 value = action.const
  2426.             else:
  2427.                 value = action.default
  2428.             if isinstance(value, str):
  2429.                 value = self._get_value(action, value)
  2430.                 self._check_value(action, value)
  2432.         # when nargs='*' on a positional, if there were no command-line
  2433.         # args, use the default if it is anything other than None
  2434.         elif (not arg_strings and action.nargs == ZERO_OR_MORE and
  2435.               not action.option_strings):
  2436.             if action.default is not None:
  2437.                 value = action.default
  2438.             else:
  2439.                 value = arg_strings
  2440.             self._check_value(action, value)
  2442.         # single argument or optional argument produces a single value
  2443.         elif len(arg_strings) == 1 and action.nargs in [None, OPTIONAL]:
  2444.             arg_string, = arg_strings
  2445.             value = self._get_value(action, arg_string)
  2446.             self._check_value(action, value)
  2448.         # REMAINDER arguments convert all values, checking none
  2449.         elif action.nargs == REMAINDER:
  2450.             value = [self._get_value(action, v) for v in arg_strings]
  2452.         # PARSER arguments convert all values, but check only the first
  2453.         elif action.nargs == PARSER:
  2454.             value = [self._get_value(action, v) for v in arg_strings]
  2455.             self._check_value(action, value[0])
  2457.         # SUPPRESS argument does not put anything in the namespace
  2458.         elif action.nargs == SUPPRESS:
  2459.             value = SUPPRESS
  2461.         # all other types of nargs produce a list
  2462.         else:
  2463.             value = [self._get_value(action, v) for v in arg_strings]
  2464.             for v in value:
  2465.                 self._check_value(action, v)
  2467.         # return the converted value
  2468.         return value
  2470.     def _get_value(self, action, arg_string):
  2471.         type_func = self._registry_get('type', action.type, action.type)
  2472.         if not callable(type_func):
  2473.             msg = _('%r is not callable')
  2474.             raise ArgumentError(action, msg % type_func)
  2476.         # convert the value to the appropriate type
  2477.         try:
  2478.             result = type_func(arg_string)
  2480.         # ArgumentTypeErrors indicate errors
  2481.         except ArgumentTypeError:
  2482.             name = getattr(action.type, '__name__', repr(action.type))
  2483.             msg = str(_sys.exc_info()[1])
  2484.             raise ArgumentError(action, msg)
  2486.         # TypeErrors or ValueErrors also indicate errors
  2487.         except (TypeError, ValueError):
  2488.             name = getattr(action.type, '__name__', repr(action.type))
  2489.             args = {'type': name, 'value': arg_string}
  2490.             msg = _('invalid %(type)s value: %(value)r')
  2491.             raise ArgumentError(action, msg % args)
  2493.         # return the converted value
  2494.         return result
  2496.     def _check_value(self, action, value):
  2497.         # converted value must be one of the choices (if specified)
  2498.         if action.choices is not None and value not in action.choices:
  2499.             args = {'value': value,
  2500.                     'choices': ', '.join(map(repr, action.choices))}
  2501.             msg = _('invalid choice: %(value)r (choose from %(choices)s)')
  2502.             raise ArgumentError(action, msg % args)
  2504.     # =======================
  2505.     # Help-formatting methods
  2506.     # =======================
  2507.     def format_usage(self):
  2508.         formatter = self._get_formatter()
  2509.         formatter.add_usage(self.usage, self._actions,
  2510.                             self._mutually_exclusive_groups)
  2511.         return formatter.format_help()
  2513.     def format_help(self):
  2514.         formatter = self._get_formatter()
  2516.         # usage
  2517.         formatter.add_usage(self.usage, self._actions,
  2518.                             self._mutually_exclusive_groups)
  2520.         # description
  2521.         formatter.add_text(self.description)
  2523.         # positionals, optionals and user-defined groups
  2524.         for action_group in self._action_groups:
  2525.             formatter.start_section(action_group.title)
  2526.             formatter.add_text(action_group.description)
  2527.             formatter.add_arguments(action_group._group_actions)
  2528.             formatter.end_section()
  2530.         # epilog
  2531.         formatter.add_text(self.epilog)
  2533.         # determine help from format above
  2534.         return formatter.format_help()
  2536.     def _get_formatter(self):
  2537.         return self.formatter_class(prog=self.prog)
  2539.     # =====================
  2540.     # Help-printing methods
  2541.     # =====================
  2542.     def print_usage(self, file=None):
  2543.         if file is None:
  2544.             file = _sys.stdout
  2545.         self._print_message(self.format_usage(), file)
  2547.     def print_help(self, file=None):
  2548.         if file is None:
  2549.             file = _sys.stdout
  2550.         self._print_message(self.format_help(), file)
  2552.     def _print_message(self, message, file=None):
  2553.         if message:
  2554.             if file is None:
  2555.                 file = _sys.stderr
  2556.             file.write(message)
  2558.     # ===============
  2559.     # Exiting methods
  2560.     # ===============
  2561.     def exit(self, status=0, message=None):
  2562.         if message:
  2563.             self._print_message(message, _sys.stderr)
  2564.         _sys.exit(status)
  2566.     def error(self, message):
  2567.         """error(message: string)
  2569.         Prints a usage message incorporating the message to stderr and
  2570.         exits.
  2572.         If you override this in a subclass, it should not return -- it
  2573.         should either exit or raise an exception.
  2574.         """
  2575.         self.print_usage(_sys.stderr)
  2576.         args = {'prog': self.prog, 'message': message}
  2577.         self.exit(2, _('%(prog)s: error: %(message)s\n') % args)