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argparse.py95.8 KB · 2583 lines
# Author: Steven J. Bethard <steven.bethard@gmail.com>.# New maintainer as of 29 August 2019:  Raymond Hettinger <raymond.hettinger@gmail.com> """Command-line parsing library This module is an optparse-inspired command-line parsing library that:     - handles both optional and positional arguments    - produces highly informative usage messages    - supports parsers that dispatch to sub-parsers The following is a simple usage example that sums integers from thecommand-line and writes the result to a file::     parser = argparse.ArgumentParser(        description='sum the integers at the command line')    parser.add_argument(        'integers', metavar='int', nargs='+', type=int,        help='an integer to be summed')    parser.add_argument(        '--log', default=sys.stdout, type=argparse.FileType('w'),        help='the file where the sum should be written')    args = parser.parse_args()    args.log.write('%s' % sum(args.integers))    args.log.close() The module contains the following public classes:     - ArgumentParser -- The main entry point for command-line parsing. As the        example above shows, the add_argument() method is used to populate        the parser with actions for optional and positional arguments. Then        the parse_args() method is invoked to convert the args at the        command-line into an object with attributes.     - ArgumentError -- The exception raised by ArgumentParser objects when        there are errors with the parser's actions. Errors raised while        parsing the command-line are caught by ArgumentParser and emitted        as command-line messages.     - FileType -- A factory for defining types of files to be created. As the        example above shows, instances of FileType are typically passed as        the type= argument of add_argument() calls.     - Action -- The base class for parser actions. Typically actions are        selected by passing strings like 'store_true' or 'append_const' to        the action= argument of add_argument(). However, for greater        customization of ArgumentParser actions, subclasses of Action may        be defined and passed as the action= argument.     - HelpFormatter, RawDescriptionHelpFormatter, RawTextHelpFormatter,        ArgumentDefaultsHelpFormatter -- Formatter classes which        may be passed as the formatter_class= argument to the        ArgumentParser constructor. HelpFormatter is the default,        RawDescriptionHelpFormatter and RawTextHelpFormatter tell the parser        not to change the formatting for help text, and        ArgumentDefaultsHelpFormatter adds information about argument defaults        to the help. All other classes in this module are considered implementation details.(Also note that HelpFormatter and RawDescriptionHelpFormatter are onlyconsidered public as object names -- the API of the formatter objects isstill considered an implementation detail.)""" __version__ = '1.1'__all__ = [    'ArgumentParser',    'ArgumentError',    'ArgumentTypeError',    'BooleanOptionalAction',    'FileType',    'HelpFormatter',    'ArgumentDefaultsHelpFormatter',    'RawDescriptionHelpFormatter',    'RawTextHelpFormatter',    'MetavarTypeHelpFormatter',    'Namespace',    'Action',    'ONE_OR_MORE',    'OPTIONAL',    'PARSER',    'REMAINDER',    'SUPPRESS',    'ZERO_OR_MORE',]  import os as _osimport re as _reimport sys as _sys from gettext import gettext as _, ngettext SUPPRESS = '==SUPPRESS==' OPTIONAL = '?'ZERO_OR_MORE = '*'ONE_OR_MORE = '+'PARSER = 'A...'REMAINDER = '...'_UNRECOGNIZED_ARGS_ATTR = '_unrecognized_args' # =============================# Utility functions and classes# ============================= class _AttributeHolder(object):    """Abstract base class that provides __repr__.     The __repr__ method returns a string in the format::        ClassName(attr=name, attr=name, ...)    The attributes are determined either by a class-level attribute,    '_kwarg_names', or by inspecting the instance __dict__.    """     def __repr__(self):        type_name = type(self).__name__        arg_strings = []        star_args = {}        for arg in self._get_args():            arg_strings.append(repr(arg))        for name, value in self._get_kwargs():            if name.isidentifier():                arg_strings.append('%s=%r' % (name, value))            else:                star_args[name] = value        if star_args:            arg_strings.append('**%s' % repr(star_args))        return '%s(%s)' % (type_name, ', '.join(arg_strings))     def _get_kwargs(self):        return list(self.__dict__.items())     def _get_args(self):        return []  def _copy_items(items):    if items is None:        return []    # The copy module is used only in the 'append' and 'append_const'    # actions, and it is needed only when the default value isn't a list.    # Delay its import for speeding up the common case.    if type(items) is list:        return items[:]    import copy    return copy.copy(items)  # ===============# Formatting Help# =============== class HelpFormatter(object):    """Formatter for generating usage messages and argument help strings.     Only the name of this class is considered a public API. All the methods    provided by the class are considered an implementation detail.    """     def __init__(self,                 prog,                 indent_increment=2,                 max_help_position=24,                 width=None):         # default setting for width        if width is None:            import shutil            width = shutil.get_terminal_size().columns            width -= 2         self._prog = prog        self._indent_increment = indent_increment        self._max_help_position = min(max_help_position,                                      max(width - 20, indent_increment * 2))        self._width = width         self._current_indent = 0        self._level = 0        self._action_max_length = 0         self._root_section = self._Section(self, None)        self._current_section = self._root_section         self._whitespace_matcher = _re.compile(r'\s+', _re.ASCII)        self._long_break_matcher = _re.compile(r'\n\n\n+')     # ===============================    # Section and indentation methods    # ===============================    def _indent(self):        self._current_indent += self._indent_increment        self._level += 1     def _dedent(self):        self._current_indent -= self._indent_increment        assert self._current_indent >= 0, 'Indent decreased below 0.'        self._level -= 1     class _Section(object):         def __init__(self, formatter, parent, heading=None):            self.formatter = formatter            self.parent = parent            self.heading = heading            self.items = []         def format_help(self):            # format the indented section            if self.parent is not None:                self.formatter._indent()            join = self.formatter._join_parts            item_help = join([func(*args) for func, args in self.items])            if self.parent is not None:                self.formatter._dedent()             # return nothing if the section was empty            if not item_help:                return ''             # add the heading if the section was non-empty            if self.heading is not SUPPRESS and self.heading is not None:                current_indent = self.formatter._current_indent                heading = '%*s%s:\n' % (current_indent, '', self.heading)            else:                heading = ''             # join the section-initial newline, the heading and the help            return join(['\n', heading, item_help, '\n'])     def _add_item(self, func, args):        self._current_section.items.append((func, args))     # ========================    # Message building methods    # ========================    def start_section(self, heading):        self._indent()        section = self._Section(self, self._current_section, heading)        self._add_item(section.format_help, [])        self._current_section = section     def end_section(self):        self._current_section = self._current_section.parent        self._dedent()     def add_text(self, text):        if text is not SUPPRESS and text is not None:            self._add_item(self._format_text, [text])     def add_usage(self, usage, actions, groups, prefix=None):        if usage is not SUPPRESS:            args = usage, actions, groups, prefix            self._add_item(self._format_usage, args)     def add_argument(self, action):        if action.help is not SUPPRESS:             # find all invocations            get_invocation = self._format_action_invocation            invocations = [get_invocation(action)]            for subaction in self._iter_indented_subactions(action):                invocations.append(get_invocation(subaction))             # update the maximum item length            invocation_length = max(map(len, invocations))            action_length = invocation_length + self._current_indent            self._action_max_length = max(self._action_max_length,                                          action_length)             # add the item to the list            self._add_item(self._format_action, [action])     def add_arguments(self, actions):        for action in actions:            self.add_argument(action)     # =======================    # Help-formatting methods    # =======================    def format_help(self):        help = self._root_section.format_help()        if help:            help = self._long_break_matcher.sub('\n\n', help)            help = help.strip('\n') + '\n'        return help     def _join_parts(self, part_strings):        return ''.join([part                        for part in part_strings                        if part and part is not SUPPRESS])     def _format_usage(self, usage, actions, groups, prefix):        if prefix is None:            prefix = _('usage: ')         # if usage is specified, use that        if usage is not None:            usage = usage % dict(prog=self._prog)         # if no optionals or positionals are available, usage is just prog        elif usage is None and not actions:            usage = '%(prog)s' % dict(prog=self._prog)         # if optionals and positionals are available, calculate usage        elif usage is None:            prog = '%(prog)s' % dict(prog=self._prog)             # split optionals from positionals            optionals = []            positionals = []            for action in actions:                if action.option_strings:                    optionals.append(action)                else:                    positionals.append(action)             # build full usage string            format = self._format_actions_usage            action_usage = format(optionals + positionals, groups)            usage = ' '.join([s for s in [prog, action_usage] if s])             # wrap the usage parts if it's too long            text_width = self._width - self._current_indent            if len(prefix) + len(usage) > text_width:                 # break usage into wrappable parts                part_regexp = (                    r'\(.*?\)+(?=\s|$)|'                    r'\[.*?\]+(?=\s|$)|'                    r'\S+'                )                opt_usage = format(optionals, groups)                pos_usage = format(positionals, groups)                opt_parts = _re.findall(part_regexp, opt_usage)                pos_parts = _re.findall(part_regexp, pos_usage)                assert ' '.join(opt_parts) == opt_usage                assert ' '.join(pos_parts) == pos_usage                 # helper for wrapping lines                def get_lines(parts, indent, prefix=None):                    lines = []                    line = []                    if prefix is not None:                        line_len = len(prefix) - 1                    else:                        line_len = len(indent) - 1                    for part in parts:                        if line_len + 1 + len(part) > text_width and line:                            lines.append(indent + ' '.join(line))                            line = []                            line_len = len(indent) - 1                        line.append(part)                        line_len += len(part) + 1                    if line:                        lines.append(indent + ' '.join(line))                    if prefix is not None:                        lines[0] = lines[0][len(indent):]                    return lines                 # if prog is short, follow it with optionals or positionals                if len(prefix) + len(prog) <= 0.75 * text_width:                    indent = ' ' * (len(prefix) + len(prog) + 1)                    if opt_parts:                        lines = get_lines([prog] + opt_parts, indent, prefix)                        lines.extend(get_lines(pos_parts, indent))                    elif pos_parts:                        lines = get_lines([prog] + pos_parts, indent, prefix)                    else:                        lines = [prog]                 # if prog is long, put it on its own line                else:                    indent = ' ' * len(prefix)                    parts = opt_parts + pos_parts                    lines = get_lines(parts, indent)                    if len(lines) > 1:                        lines = []                        lines.extend(get_lines(opt_parts, indent))                        lines.extend(get_lines(pos_parts, indent))                    lines = [prog] + lines                 # join lines into usage                usage = '\n'.join(lines)         # prefix with 'usage:'        return '%s%s\n\n' % (prefix, usage)     def _format_actions_usage(self, actions, groups):        # find group indices and identify actions in groups        group_actions = set()        inserts = {}        for group in groups:            if not group._group_actions:                raise ValueError(f'empty group {group}')             try:                start = actions.index(group._group_actions[0])            except ValueError:                continue            else:                end = start + len(group._group_actions)                if actions[start:end] == group._group_actions:                    for action in group._group_actions:                        group_actions.add(action)                    if not group.required:                        if start in inserts:                            inserts[start] += ' ['                        else:                            inserts[start] = '['                        if end in inserts:                            inserts[end] += ']'                        else:                            inserts[end] = ']'                    else:                        if start in inserts:                            inserts[start] += ' ('                        else:                            inserts[start] = '('                        if end in inserts:                            inserts[end] += ')'                        else:                            inserts[end] = ')'                    for i in range(start + 1, end):                        inserts[i] = '|'         # collect all actions format strings        parts = []        for i, action in enumerate(actions):             # suppressed arguments are marked with None            # remove | separators for suppressed arguments            if action.help is SUPPRESS:                parts.append(None)                if inserts.get(i) == '|':                    inserts.pop(i)                elif inserts.get(i + 1) == '|':                    inserts.pop(i + 1)             # produce all arg strings            elif not action.option_strings:                default = self._get_default_metavar_for_positional(action)                part = self._format_args(action, default)                 # if it's in a group, strip the outer []                if action in group_actions:                    if part[0] == '[' and part[-1] == ']':                        part = part[1:-1]                 # add the action string to the list                parts.append(part)             # produce the first way to invoke the option in brackets            else:                option_string = action.option_strings[0]                 # if the Optional doesn't take a value, format is:                #    -s or --long                if action.nargs == 0:                    part = action.format_usage()                 # if the Optional takes a value, format is:                #    -s ARGS or --long ARGS                else:                    default = self._get_default_metavar_for_optional(action)                    args_string = self._format_args(action, default)                    part = '%s %s' % (option_string, args_string)                 # make it look optional if it's not required or in a group                if not action.required and action not in group_actions:                    part = '[%s]' % part                 # add the action string to the list                parts.append(part)         # insert things at the necessary indices        for i in sorted(inserts, reverse=True):            parts[i:i] = [inserts[i]]         # join all the action items with spaces        text = ' '.join([item for item in parts if item is not None])         # clean up separators for mutually exclusive groups        open = r'[\[(]'        close = r'[\])]'        text = _re.sub(r'(%s) ' % open, r'\1', text)        text = _re.sub(r' (%s)' % close, r'\1', text)        text = _re.sub(r'%s *%s' % (open, close), r'', text)        text = _re.sub(r'\(([^|]*)\)', r'\1', text)        text = text.strip()         # return the text        return text     def _format_text(self, text):        if '%(prog)' in text:            text = text % dict(prog=self._prog)        text_width = max(self._width - self._current_indent, 11)        indent = ' ' * self._current_indent        return self._fill_text(text, text_width, indent) + '\n\n'     def _format_action(self, action):        # determine the required width and the entry label        help_position = min(self._action_max_length + 2,                            self._max_help_position)        help_width = max(self._width - help_position, 11)        action_width = help_position - self._current_indent - 2        action_header = self._format_action_invocation(action)         # no help; start on same line and add a final newline        if not action.help:            tup = self._current_indent, '', action_header            action_header = '%*s%s\n' % tup         # short action name; start on the same line and pad two spaces        elif len(action_header) <= action_width:            tup = self._current_indent, '', action_width, action_header            action_header = '%*s%-*s  ' % tup            indent_first = 0         # long action name; start on the next line        else:            tup = self._current_indent, '', action_header            action_header = '%*s%s\n' % tup            indent_first = help_position         # collect the pieces of the action help        parts = [action_header]         # if there was help for the action, add lines of help text        if action.help and action.help.strip():            help_text = self._expand_help(action)            if help_text:                help_lines = self._split_lines(help_text, help_width)                parts.append('%*s%s\n' % (indent_first, '', help_lines[0]))                for line in help_lines[1:]:                    parts.append('%*s%s\n' % (help_position, '', line))         # or add a newline if the description doesn't end with one        elif not action_header.endswith('\n'):            parts.append('\n')         # if there are any sub-actions, add their help as well        for subaction in self._iter_indented_subactions(action):            parts.append(self._format_action(subaction))         # return a single string        return self._join_parts(parts)     def _format_action_invocation(self, action):        if not action.option_strings:            default = self._get_default_metavar_for_positional(action)            metavar, = self._metavar_formatter(action, default)(1)            return metavar         else:            parts = []             # if the Optional doesn't take a value, format is:            #    -s, --long            if action.nargs == 0:                parts.extend(action.option_strings)             # if the Optional takes a value, format is:            #    -s ARGS, --long ARGS            else:                default = self._get_default_metavar_for_optional(action)                args_string = self._format_args(action, default)                for option_string in action.option_strings:                    parts.append('%s %s' % (option_string, args_string))             return ', '.join(parts)     def _metavar_formatter(self, action, default_metavar):        if action.metavar is not None:            result = action.metavar        elif action.choices is not None:            choice_strs = [str(choice) for choice in action.choices]            result = '{%s}' % ','.join(choice_strs)        else:            result = default_metavar         def format(tuple_size):            if isinstance(result, tuple):                return result            else:                return (result, ) * tuple_size        return format     def _format_args(self, action, default_metavar):        get_metavar = self._metavar_formatter(action, default_metavar)        if action.nargs is None:            result = '%s' % get_metavar(1)        elif action.nargs == OPTIONAL:            result = '[%s]' % get_metavar(1)        elif action.nargs == ZERO_OR_MORE:            metavar = get_metavar(1)            if len(metavar) == 2:                result = '[%s [%s ...]]' % metavar            else:                result = '[%s ...]' % metavar        elif action.nargs == ONE_OR_MORE:            result = '%s [%s ...]' % get_metavar(2)        elif action.nargs == REMAINDER:            result = '...'        elif action.nargs == PARSER:            result = '%s ...' % get_metavar(1)        elif action.nargs == SUPPRESS:            result = ''        else:            try:                formats = ['%s' for _ in range(action.nargs)]            except TypeError:                raise ValueError("invalid nargs value") from None            result = ' '.join(formats) % get_metavar(action.nargs)        return result     def _expand_help(self, action):        params = dict(vars(action), prog=self._prog)        for name in list(params):            if params[name] is SUPPRESS:                del params[name]        for name in list(params):            if hasattr(params[name], '__name__'):                params[name] = params[name].__name__        if params.get('choices') is not None:            choices_str = ', '.join([str(c) for c in params['choices']])            params['choices'] = choices_str        return self._get_help_string(action) % params     def _iter_indented_subactions(self, action):        try:            get_subactions = action._get_subactions        except AttributeError:            pass        else:            self._indent()            yield from get_subactions()            self._dedent()     def _split_lines(self, text, width):        text = self._whitespace_matcher.sub(' ', text).strip()        # The textwrap module is used only for formatting help.        # Delay its import for speeding up the common usage of argparse.        import textwrap        return textwrap.wrap(text, width)     def _fill_text(self, text, width, indent):        text = self._whitespace_matcher.sub(' ', text).strip()        import textwrap        return textwrap.fill(text, width,                             initial_indent=indent,                             subsequent_indent=indent)     def _get_help_string(self, action):        return action.help     def _get_default_metavar_for_optional(self, action):        return action.dest.upper()     def _get_default_metavar_for_positional(self, action):        return action.dest  class RawDescriptionHelpFormatter(HelpFormatter):    """Help message formatter which retains any formatting in descriptions.     Only the name of this class is considered a public API. All the methods    provided by the class are considered an implementation detail.    """     def _fill_text(self, text, width, indent):        return ''.join(indent + line for line in text.splitlines(keepends=True))  class RawTextHelpFormatter(RawDescriptionHelpFormatter):    """Help message formatter which retains formatting of all help text.     Only the name of this class is considered a public API. All the methods    provided by the class are considered an implementation detail.    """     def _split_lines(self, text, width):        return text.splitlines()  class ArgumentDefaultsHelpFormatter(HelpFormatter):    """Help message formatter which adds default values to argument help.     Only the name of this class is considered a public API. All the methods    provided by the class are considered an implementation detail.    """     def _get_help_string(self, action):        help = action.help        if '%(default)' not in action.help:            if action.default is not SUPPRESS:                defaulting_nargs = [OPTIONAL, ZERO_OR_MORE]                if action.option_strings or action.nargs in defaulting_nargs:                    help += ' (default: %(default)s)'        return help  class MetavarTypeHelpFormatter(HelpFormatter):    """Help message formatter which uses the argument 'type' as the default    metavar value (instead of the argument 'dest')     Only the name of this class is considered a public API. All the methods    provided by the class are considered an implementation detail.    """     def _get_default_metavar_for_optional(self, action):        return action.type.__name__     def _get_default_metavar_for_positional(self, action):        return action.type.__name__   # =====================# Options and Arguments# ===================== def _get_action_name(argument):    if argument is None:        return None    elif argument.option_strings:        return '/'.join(argument.option_strings)    elif argument.metavar not in (None, SUPPRESS):        return argument.metavar    elif argument.dest not in (None, SUPPRESS):        return argument.dest    elif argument.choices:        return '{' + ','.join(argument.choices) + '}'    else:        return None  class ArgumentError(Exception):    """An error from creating or using an argument (optional or positional).     The string value of this exception is the message, augmented with    information about the argument that caused it.    """     def __init__(self, argument, message):        self.argument_name = _get_action_name(argument)        self.message = message     def __str__(self):        if self.argument_name is None:            format = '%(message)s'        else:            format = 'argument %(argument_name)s: %(message)s'        return format % dict(message=self.message,                             argument_name=self.argument_name)  class ArgumentTypeError(Exception):    """An error from trying to convert a command line string to a type."""    pass  # ==============# Action classes# ============== class Action(_AttributeHolder):    """Information about how to convert command line strings to Python objects.     Action objects are used by an ArgumentParser to represent the information    needed to parse a single argument from one or more strings from the    command line. The keyword arguments to the Action constructor are also    all attributes of Action instances.     Keyword Arguments:         - option_strings -- A list of command-line option strings which            should be associated with this action.         - dest -- The name of the attribute to hold the created object(s)         - nargs -- The number of command-line arguments that should be            consumed. By default, one argument will be consumed and a single            value will be produced.  Other values include:                - N (an integer) consumes N arguments (and produces a list)                - '?' consumes zero or one arguments                - '*' consumes zero or more arguments (and produces a list)                - '+' consumes one or more arguments (and produces a list)            Note that the difference between the default and nargs=1 is that            with the default, a single value will be produced, while with            nargs=1, a list containing a single value will be produced.         - const -- The value to be produced if the option is specified and the            option uses an action that takes no values.         - default -- The value to be produced if the option is not specified.         - type -- A callable that accepts a single string argument, and            returns the converted value.  The standard Python types str, int,            float, and complex are useful examples of such callables.  If None,            str is used.         - choices -- A container of values that should be allowed. If not None,            after a command-line argument has been converted to the appropriate            type, an exception will be raised if it is not a member of this            collection.         - required -- True if the action must always be specified at the            command line. This is only meaningful for optional command-line            arguments.         - help -- The help string describing the argument.         - metavar -- The name to be used for the option's argument with the            help string. If None, the 'dest' value will be used as the name.    """     def __init__(self,                 option_strings,                 dest,                 nargs=None,                 const=None,                 default=None,                 type=None,                 choices=None,                 required=False,                 help=None,                 metavar=None):        self.option_strings = option_strings        self.dest = dest        self.nargs = nargs        self.const = const        self.default = default        self.type = type        self.choices = choices        self.required = required        self.help = help        self.metavar = metavar     def _get_kwargs(self):        names = [            'option_strings',            'dest',            'nargs',            'const',            'default',            'type',            'choices',            'required',            'help',            'metavar',        ]        return [(name, getattr(self, name)) for name in names]     def format_usage(self):        return self.option_strings[0]     def __call__(self, parser, namespace, values, option_string=None):        raise NotImplementedError(_('.__call__() not defined')) class BooleanOptionalAction(Action):    def __init__(self,                 option_strings,                 dest,                 default=None,                 type=None,                 choices=None,                 required=False,                 help=None,                 metavar=None):         _option_strings = []        for option_string in option_strings:            _option_strings.append(option_string)             if option_string.startswith('--'):                option_string = '--no-' + option_string[2:]                _option_strings.append(option_string)         if help is not None and default is not None and default is not SUPPRESS:            help += " (default: %(default)s)"         super().__init__(            option_strings=_option_strings,            dest=dest,            nargs=0,            default=default,            type=type,            choices=choices,            required=required,            help=help,            metavar=metavar)     def __call__(self, parser, namespace, values, option_string=None):        if option_string in self.option_strings:            setattr(namespace, self.dest, not option_string.startswith('--no-'))     def format_usage(self):        return ' | '.join(self.option_strings)  class _StoreAction(Action):     def __init__(self,                 option_strings,                 dest,                 nargs=None,                 const=None,                 default=None,                 type=None,                 choices=None,                 required=False,                 help=None,                 metavar=None):        if nargs == 0:            raise ValueError('nargs for store actions must be != 0; if you '                             'have nothing to store, actions such as store '                             'true or store const may be more appropriate')        if const is not None and nargs != OPTIONAL:            raise ValueError('nargs must be %r to supply const' % OPTIONAL)        super(_StoreAction, self).__init__(            option_strings=option_strings,            dest=dest,            nargs=nargs,            const=const,            default=default,            type=type,            choices=choices,            required=required,            help=help,            metavar=metavar)     def __call__(self, parser, namespace, values, option_string=None):        setattr(namespace, self.dest, values)  class _StoreConstAction(Action):     def __init__(self,                 option_strings,                 dest,                 const,                 default=None,                 required=False,                 help=None,                 metavar=None):        super(_StoreConstAction, self).__init__(            option_strings=option_strings,            dest=dest,            nargs=0,            const=const,            default=default,            required=required,            help=help)     def __call__(self, parser, namespace, values, option_string=None):        setattr(namespace, self.dest, self.const)  class _StoreTrueAction(_StoreConstAction):     def __init__(self,                 option_strings,                 dest,                 default=False,                 required=False,                 help=None):        super(_StoreTrueAction, self).__init__(            option_strings=option_strings,            dest=dest,            const=True,            default=default,            required=required,            help=help)  class _StoreFalseAction(_StoreConstAction):     def __init__(self,                 option_strings,                 dest,                 default=True,                 required=False,                 help=None):        super(_StoreFalseAction, self).__init__(            option_strings=option_strings,            dest=dest,            const=False,            default=default,            required=required,            help=help)  class _AppendAction(Action):     def __init__(self,                 option_strings,                 dest,                 nargs=None,                 const=None,                 default=None,                 type=None,                 choices=None,                 required=False,                 help=None,                 metavar=None):        if nargs == 0:            raise ValueError('nargs for append actions must be != 0; if arg '                             'strings are not supplying the value to append, '                             'the append const action may be more appropriate')        if const is not None and nargs != OPTIONAL:            raise ValueError('nargs must be %r to supply const' % OPTIONAL)        super(_AppendAction, self).__init__(            option_strings=option_strings,            dest=dest,            nargs=nargs,            const=const,            default=default,            type=type,            choices=choices,            required=required,            help=help,            metavar=metavar)     def __call__(self, parser, namespace, values, option_string=None):        items = getattr(namespace, self.dest, None)        items = _copy_items(items)        items.append(values)        setattr(namespace, self.dest, items)  class _AppendConstAction(Action):     def __init__(self,                 option_strings,                 dest,                 const,                 default=None,                 required=False,                 help=None,                 metavar=None):        super(_AppendConstAction, self).__init__(            option_strings=option_strings,            dest=dest,            nargs=0,            const=const,            default=default,            required=required,            help=help,            metavar=metavar)     def __call__(self, parser, namespace, values, option_string=None):        items = getattr(namespace, self.dest, None)        items = _copy_items(items)        items.append(self.const)        setattr(namespace, self.dest, items)  class _CountAction(Action):     def __init__(self,                 option_strings,                 dest,                 default=None,                 required=False,                 help=None):        super(_CountAction, self).__init__(            option_strings=option_strings,            dest=dest,            nargs=0,            default=default,            required=required,            help=help)     def __call__(self, parser, namespace, values, option_string=None):        count = getattr(namespace, self.dest, None)        if count is None:            count = 0        setattr(namespace, self.dest, count + 1)  class _HelpAction(Action):     def __init__(self,                 option_strings,                 dest=SUPPRESS,                 default=SUPPRESS,                 help=None):        super(_HelpAction, self).__init__(            option_strings=option_strings,            dest=dest,            default=default,            nargs=0,            help=help)     def __call__(self, parser, namespace, values, option_string=None):        parser.print_help()        parser.exit()  class _VersionAction(Action):     def __init__(self,                 option_strings,                 version=None,                 dest=SUPPRESS,                 default=SUPPRESS,                 help="show program's version number and exit"):        super(_VersionAction, self).__init__(            option_strings=option_strings,            dest=dest,            default=default,            nargs=0,            help=help)        self.version = version     def __call__(self, parser, namespace, values, option_string=None):        version = self.version        if version is None:            version = parser.version        formatter = parser._get_formatter()        formatter.add_text(version)        parser._print_message(formatter.format_help(), _sys.stdout)        parser.exit()  class _SubParsersAction(Action):     class _ChoicesPseudoAction(Action):         def __init__(self, name, aliases, help):            metavar = dest = name            if aliases:                metavar += ' (%s)' % ', '.join(aliases)            sup = super(_SubParsersAction._ChoicesPseudoAction, self)            sup.__init__(option_strings=[], dest=dest, help=help,                         metavar=metavar)     def __init__(self,                 option_strings,                 prog,                 parser_class,                 dest=SUPPRESS,                 required=False,                 help=None,                 metavar=None):         self._prog_prefix = prog        self._parser_class = parser_class        self._name_parser_map = {}        self._choices_actions = []         super(_SubParsersAction, self).__init__(            option_strings=option_strings,            dest=dest,            nargs=PARSER,            choices=self._name_parser_map,            required=required,            help=help,            metavar=metavar)     def add_parser(self, name, **kwargs):        # set prog from the existing prefix        if kwargs.get('prog') is None:            kwargs['prog'] = '%s %s' % (self._prog_prefix, name)         aliases = kwargs.pop('aliases', ())         # create a pseudo-action to hold the choice help        if 'help' in kwargs:            help = kwargs.pop('help')            choice_action = self._ChoicesPseudoAction(name, aliases, help)            self._choices_actions.append(choice_action)         # create the parser and add it to the map        parser = self._parser_class(**kwargs)        self._name_parser_map[name] = parser         # make parser available under aliases also        for alias in aliases:            self._name_parser_map[alias] = parser         return parser     def _get_subactions(self):        return self._choices_actions     def __call__(self, parser, namespace, values, option_string=None):        parser_name = values[0]        arg_strings = values[1:]         # set the parser name if requested        if self.dest is not SUPPRESS:            setattr(namespace, self.dest, parser_name)         # select the parser        try:            parser = self._name_parser_map[parser_name]        except KeyError:            args = {'parser_name': parser_name,                    'choices': ', '.join(self._name_parser_map)}            msg = _('unknown parser %(parser_name)r (choices: %(choices)s)') % args            raise ArgumentError(self, msg)         # parse all the remaining options into the namespace        # store any unrecognized options on the object, so that the top        # level parser can decide what to do with them         # In case this subparser defines new defaults, we parse them        # in a new namespace object and then update the original        # namespace for the relevant parts.        subnamespace, arg_strings = parser.parse_known_args(arg_strings, None)        for key, value in vars(subnamespace).items():            setattr(namespace, key, value)         if arg_strings:            vars(namespace).setdefault(_UNRECOGNIZED_ARGS_ATTR, [])            getattr(namespace, _UNRECOGNIZED_ARGS_ATTR).extend(arg_strings) class _ExtendAction(_AppendAction):    def __call__(self, parser, namespace, values, option_string=None):        items = getattr(namespace, self.dest, None)        items = _copy_items(items)        items.extend(values)        setattr(namespace, self.dest, items) # ==============# Type classes# ============== class FileType(object):    """Factory for creating file object types     Instances of FileType are typically passed as type= arguments to the    ArgumentParser add_argument() method.     Keyword Arguments:        - mode -- A string indicating how the file is to be opened. Accepts the            same values as the builtin open() function.        - bufsize -- The file's desired buffer size. Accepts the same values as            the builtin open() function.        - encoding -- The file's encoding. Accepts the same values as the            builtin open() function.        - errors -- A string indicating how encoding and decoding errors are to            be handled. Accepts the same value as the builtin open() function.    """     def __init__(self, mode='r', bufsize=-1, encoding=None, errors=None):        self._mode = mode        self._bufsize = bufsize        self._encoding = encoding        self._errors = errors     def __call__(self, string):        # the special argument "-" means sys.std{in,out}        if string == '-':            if 'r' in self._mode:                return _sys.stdin.buffer if 'b' in self._mode else _sys.stdin            elif any(c in self._mode for c in 'wax'):                return _sys.stdout.buffer if 'b' in self._mode else _sys.stdout            else:                msg = _('argument "-" with mode %r') % self._mode                raise ValueError(msg)         # all other arguments are used as file names        try:            return open(string, self._mode, self._bufsize, self._encoding,                        self._errors)        except OSError as e:            args = {'filename': string, 'error': e}            message = _("can't open '%(filename)s': %(error)s")            raise ArgumentTypeError(message % args)     def __repr__(self):        args = self._mode, self._bufsize        kwargs = [('encoding', self._encoding), ('errors', self._errors)]        args_str = ', '.join([repr(arg) for arg in args if arg != -1] +                             ['%s=%r' % (kw, arg) for kw, arg in kwargs                              if arg is not None])        return '%s(%s)' % (type(self).__name__, args_str) # ===========================# Optional and Positional Parsing# =========================== class Namespace(_AttributeHolder):    """Simple object for storing attributes.     Implements equality by attribute names and values, and provides a simple    string representation.    """     def __init__(self, **kwargs):        for name in kwargs:            setattr(self, name, kwargs[name])     def __eq__(self, other):        if not isinstance(other, Namespace):            return NotImplemented        return vars(self) == vars(other)     def __contains__(self, key):        return key in self.__dict__  class _ActionsContainer(object):     def __init__(self,                 description,                 prefix_chars,                 argument_default,                 conflict_handler):        super(_ActionsContainer, self).__init__()         self.description = description        self.argument_default = argument_default        self.prefix_chars = prefix_chars        self.conflict_handler = conflict_handler         # set up registries        self._registries = {}         # register actions        self.register('action', None, _StoreAction)        self.register('action', 'store', _StoreAction)        self.register('action', 'store_const', _StoreConstAction)        self.register('action', 'store_true', _StoreTrueAction)        self.register('action', 'store_false', _StoreFalseAction)        self.register('action', 'append', _AppendAction)        self.register('action', 'append_const', _AppendConstAction)        self.register('action', 'count', _CountAction)        self.register('action', 'help', _HelpAction)        self.register('action', 'version', _VersionAction)        self.register('action', 'parsers', _SubParsersAction)        self.register('action', 'extend', _ExtendAction)         # raise an exception if the conflict handler is invalid        self._get_handler()         # action storage        self._actions = []        self._option_string_actions = {}         # groups        self._action_groups = []        self._mutually_exclusive_groups = []         # defaults storage        self._defaults = {}         # determines whether an "option" looks like a negative number        self._negative_number_matcher = _re.compile(r'^-\d+$|^-\d*\.\d+$')         # whether or not there are any optionals that look like negative        # numbers -- uses a list so it can be shared and edited        self._has_negative_number_optionals = []     # ====================    # Registration methods    # ====================    def register(self, registry_name, value, object):        registry = self._registries.setdefault(registry_name, {})        registry[value] = object     def _registry_get(self, registry_name, value, default=None):        return self._registries[registry_name].get(value, default)     # ==================================    # Namespace default accessor methods    # ==================================    def set_defaults(self, **kwargs):        self._defaults.update(kwargs)         # if these defaults match any existing arguments, replace        # the previous default on the object with the new one        for action in self._actions:            if action.dest in kwargs:                action.default = kwargs[action.dest]     def get_default(self, dest):        for action in self._actions:            if action.dest == dest and action.default is not None:                return action.default        return self._defaults.get(dest, None)      # =======================    # Adding argument actions    # =======================    def add_argument(self, *args, **kwargs):        """        add_argument(dest, ..., name=value, ...)        add_argument(option_string, option_string, ..., name=value, ...)        """         # if no positional args are supplied or only one is supplied and        # it doesn't look like an option string, parse a positional        # argument        chars = self.prefix_chars        if not args or len(args) == 1 and args[0][0] not in chars:            if args and 'dest' in kwargs:                raise ValueError('dest supplied twice for positional argument')            kwargs = self._get_positional_kwargs(*args, **kwargs)         # otherwise, we're adding an optional argument        else:            kwargs = self._get_optional_kwargs(*args, **kwargs)         # if no default was supplied, use the parser-level default        if 'default' not in kwargs:            dest = kwargs['dest']            if dest in self._defaults:                kwargs['default'] = self._defaults[dest]            elif self.argument_default is not None:                kwargs['default'] = self.argument_default         # create the action object, and add it to the parser        action_class = self._pop_action_class(kwargs)        if not callable(action_class):            raise ValueError('unknown action "%s"' % (action_class,))        action = action_class(**kwargs)         # raise an error if the action type is not callable        type_func = self._registry_get('type', action.type, action.type)        if not callable(type_func):            raise ValueError('%r is not callable' % (type_func,))         if type_func is FileType:            raise ValueError('%r is a FileType class object, instance of it'                             ' must be passed' % (type_func,))         # raise an error if the metavar does not match the type        if hasattr(self, "_get_formatter"):            try:                self._get_formatter()._format_args(action, None)            except TypeError:                raise ValueError("length of metavar tuple does not match nargs")         return self._add_action(action)     def add_argument_group(self, *args, **kwargs):        group = _ArgumentGroup(self, *args, **kwargs)        self._action_groups.append(group)        return group     def add_mutually_exclusive_group(self, **kwargs):        group = _MutuallyExclusiveGroup(self, **kwargs)        self._mutually_exclusive_groups.append(group)        return group     def _add_action(self, action):        # resolve any conflicts        self._check_conflict(action)         # add to actions list        self._actions.append(action)        action.container = self         # index the action by any option strings it has        for option_string in action.option_strings:            self._option_string_actions[option_string] = action         # set the flag if any option strings look like negative numbers        for option_string in action.option_strings:            if self._negative_number_matcher.match(option_string):                if not self._has_negative_number_optionals:                    self._has_negative_number_optionals.append(True)         # return the created action        return action     def _remove_action(self, action):        self._actions.remove(action)     def _add_container_actions(self, container):        # collect groups by titles        title_group_map = {}        for group in self._action_groups:            if group.title in title_group_map:                msg = _('cannot merge actions - two groups are named %r')                raise ValueError(msg % (group.title))            title_group_map[group.title] = group         # map each action to its group        group_map = {}        for group in container._action_groups:             # if a group with the title exists, use that, otherwise            # create a new group matching the container's group            if group.title not in title_group_map:                title_group_map[group.title] = self.add_argument_group(                    title=group.title,                    description=group.description,                    conflict_handler=group.conflict_handler)             # map the actions to their new group            for action in group._group_actions:                group_map[action] = title_group_map[group.title]         # add container's mutually exclusive groups        # NOTE: if add_mutually_exclusive_group ever gains title= and        # description= then this code will need to be expanded as above        for group in container._mutually_exclusive_groups:            mutex_group = self.add_mutually_exclusive_group(                required=group.required)             # map the actions to their new mutex group            for action in group._group_actions:                group_map[action] = mutex_group         # add all actions to this container or their group        for action in container._actions:            group_map.get(action, self)._add_action(action)     def _get_positional_kwargs(self, dest, **kwargs):        # make sure required is not specified        if 'required' in kwargs:            msg = _("'required' is an invalid argument for positionals")            raise TypeError(msg)         # mark positional arguments as required if at least one is        # always required        if kwargs.get('nargs') not in [OPTIONAL, ZERO_OR_MORE]:            kwargs['required'] = True        if kwargs.get('nargs') == ZERO_OR_MORE and 'default' not in kwargs:            kwargs['required'] = True         # return the keyword arguments with no option strings        return dict(kwargs, dest=dest, option_strings=[])     def _get_optional_kwargs(self, *args, **kwargs):        # determine short and long option strings        option_strings = []        long_option_strings = []        for option_string in args:            # error on strings that don't start with an appropriate prefix            if not option_string[0] in self.prefix_chars:                args = {'option': option_string,                        'prefix_chars': self.prefix_chars}                msg = _('invalid option string %(option)r: '                        'must start with a character %(prefix_chars)r')                raise ValueError(msg % args)             # strings starting with two prefix characters are long options            option_strings.append(option_string)            if len(option_string) > 1 and option_string[1] in self.prefix_chars:                long_option_strings.append(option_string)         # infer destination, '--foo-bar' -> 'foo_bar' and '-x' -> 'x'        dest = kwargs.pop('dest', None)        if dest is None:            if long_option_strings:                dest_option_string = long_option_strings[0]            else:                dest_option_string = option_strings[0]            dest = dest_option_string.lstrip(self.prefix_chars)            if not dest:                msg = _('dest= is required for options like %r')                raise ValueError(msg % option_string)            dest = dest.replace('-', '_')         # return the updated keyword arguments        return dict(kwargs, dest=dest, option_strings=option_strings)     def _pop_action_class(self, kwargs, default=None):        action = kwargs.pop('action', default)        return self._registry_get('action', action, action)     def _get_handler(self):        # determine function from conflict handler string        handler_func_name = '_handle_conflict_%s' % self.conflict_handler        try:            return getattr(self, handler_func_name)        except AttributeError:            msg = _('invalid conflict_resolution value: %r')            raise ValueError(msg % self.conflict_handler)     def _check_conflict(self, action):         # find all options that conflict with this option        confl_optionals = []        for option_string in action.option_strings:            if option_string in self._option_string_actions:                confl_optional = self._option_string_actions[option_string]                confl_optionals.append((option_string, confl_optional))         # resolve any conflicts        if confl_optionals:            conflict_handler = self._get_handler()            conflict_handler(action, confl_optionals)     def _handle_conflict_error(self, action, conflicting_actions):        message = ngettext('conflicting option string: %s',                           'conflicting option strings: %s',                           len(conflicting_actions))        conflict_string = ', '.join([option_string                                     for option_string, action                                     in conflicting_actions])        raise ArgumentError(action, message % conflict_string)     def _handle_conflict_resolve(self, action, conflicting_actions):         # remove all conflicting options        for option_string, action in conflicting_actions:             # remove the conflicting option            action.option_strings.remove(option_string)            self._option_string_actions.pop(option_string, None)             # if the option now has no option string, remove it from the            # container holding it            if not action.option_strings:                action.container._remove_action(action)  class _ArgumentGroup(_ActionsContainer):     def __init__(self, container, title=None, description=None, **kwargs):        # add any missing keyword arguments by checking the container        update = kwargs.setdefault        update('conflict_handler', container.conflict_handler)        update('prefix_chars', container.prefix_chars)        update('argument_default', container.argument_default)        super_init = super(_ArgumentGroup, self).__init__        super_init(description=description, **kwargs)         # group attributes        self.title = title        self._group_actions = []         # share most attributes with the container        self._registries = container._registries        self._actions = container._actions        self._option_string_actions = container._option_string_actions        self._defaults = container._defaults        self._has_negative_number_optionals = \            container._has_negative_number_optionals        self._mutually_exclusive_groups = container._mutually_exclusive_groups     def _add_action(self, action):        action = super(_ArgumentGroup, self)._add_action(action)        self._group_actions.append(action)        return action     def _remove_action(self, action):        super(_ArgumentGroup, self)._remove_action(action)        self._group_actions.remove(action)  class _MutuallyExclusiveGroup(_ArgumentGroup):     def __init__(self, container, required=False):        super(_MutuallyExclusiveGroup, self).__init__(container)        self.required = required        self._container = container     def _add_action(self, action):        if action.required:            msg = _('mutually exclusive arguments must be optional')            raise ValueError(msg)        action = self._container._add_action(action)        self._group_actions.append(action)        return action     def _remove_action(self, action):        self._container._remove_action(action)        self._group_actions.remove(action)  class ArgumentParser(_AttributeHolder, _ActionsContainer):    """Object for parsing command line strings into Python objects.     Keyword Arguments:        - prog -- The name of the program (default: sys.argv[0])        - usage -- A usage message (default: auto-generated from arguments)        - description -- A description of what the program does        - epilog -- Text following the argument descriptions        - parents -- Parsers whose arguments should be copied into this one        - formatter_class -- HelpFormatter class for printing help messages        - prefix_chars -- Characters that prefix optional arguments        - fromfile_prefix_chars -- Characters that prefix files containing            additional arguments        - argument_default -- The default value for all arguments        - conflict_handler -- String indicating how to handle conflicts        - add_help -- Add a -h/-help option        - allow_abbrev -- Allow long options to be abbreviated unambiguously        - exit_on_error -- Determines whether or not ArgumentParser exits with            error info when an error occurs    """     def __init__(self,                 prog=None,                 usage=None,                 description=None,                 epilog=None,                 parents=[],                 formatter_class=HelpFormatter,                 prefix_chars='-',                 fromfile_prefix_chars=None,                 argument_default=None,                 conflict_handler='error',                 add_help=True,                 allow_abbrev=True,                 exit_on_error=True):         superinit = super(ArgumentParser, self).__init__        superinit(description=description,                  prefix_chars=prefix_chars,                  argument_default=argument_default,                  conflict_handler=conflict_handler)         # default setting for prog        if prog is None:            prog = _os.path.basename(_sys.argv[0])         self.prog = prog        self.usage = usage        self.epilog = epilog        self.formatter_class = formatter_class        self.fromfile_prefix_chars = fromfile_prefix_chars        self.add_help = add_help        self.allow_abbrev = allow_abbrev        self.exit_on_error = exit_on_error         add_group = self.add_argument_group        self._positionals = add_group(_('positional arguments'))        self._optionals = add_group(_('optional arguments'))        self._subparsers = None         # register types        def identity(string):            return string        self.register('type', None, identity)         # add help argument if necessary        # (using explicit default to override global argument_default)        default_prefix = '-' if '-' in prefix_chars else prefix_chars[0]        if self.add_help:            self.add_argument(                default_prefix+'h', default_prefix*2+'help',                action='help', default=SUPPRESS,                help=_('show this help message and exit'))         # add parent arguments and defaults        for parent in parents:            self._add_container_actions(parent)            try:                defaults = parent._defaults            except AttributeError:                pass            else:                self._defaults.update(defaults)     # =======================    # Pretty __repr__ methods    # =======================    def _get_kwargs(self):        names = [            'prog',            'usage',            'description',            'formatter_class',            'conflict_handler',            'add_help',        ]        return [(name, getattr(self, name)) for name in names]     # ==================================    # Optional/Positional adding methods    # ==================================    def add_subparsers(self, **kwargs):        if self._subparsers is not None:            self.error(_('cannot have multiple subparser arguments'))         # add the parser class to the arguments if it's not present        kwargs.setdefault('parser_class', type(self))         if 'title' in kwargs or 'description' in kwargs:            title = _(kwargs.pop('title', 'subcommands'))            description = _(kwargs.pop('description', None))            self._subparsers = self.add_argument_group(title, description)        else:            self._subparsers = self._positionals         # prog defaults to the usage message of this parser, skipping        # optional arguments and with no "usage:" prefix        if kwargs.get('prog') is None:            formatter = self._get_formatter()            positionals = self._get_positional_actions()            groups = self._mutually_exclusive_groups            formatter.add_usage(self.usage, positionals, groups, '')            kwargs['prog'] = formatter.format_help().strip()         # create the parsers action and add it to the positionals list        parsers_class = self._pop_action_class(kwargs, 'parsers')        action = parsers_class(option_strings=[], **kwargs)        self._subparsers._add_action(action)         # return the created parsers action        return action     def _add_action(self, action):        if action.option_strings:            self._optionals._add_action(action)        else:            self._positionals._add_action(action)        return action     def _get_optional_actions(self):        return [action                for action in self._actions                if action.option_strings]     def _get_positional_actions(self):        return [action                for action in self._actions                if not action.option_strings]     # =====================================    # Command line argument parsing methods    # =====================================    def parse_args(self, args=None, namespace=None):        args, argv = self.parse_known_args(args, namespace)        if argv:            msg = _('unrecognized arguments: %s')            self.error(msg % ' '.join(argv))        return args     def parse_known_args(self, args=None, namespace=None):        if args is None:            # args default to the system args            args = _sys.argv[1:]        else:            # make sure that args are mutable            args = list(args)         # default Namespace built from parser defaults        if namespace is None:            namespace = Namespace()         # add any action defaults that aren't present        for action in self._actions:            if action.dest is not SUPPRESS:                if not hasattr(namespace, action.dest):                    if action.default is not SUPPRESS:                        setattr(namespace, action.dest, action.default)         # add any parser defaults that aren't present        for dest in self._defaults:            if not hasattr(namespace, dest):                setattr(namespace, dest, self._defaults[dest])         # parse the arguments and exit if there are any errors        if self.exit_on_error:            try:                namespace, args = self._parse_known_args(args, namespace)            except ArgumentError:                err = _sys.exc_info()[1]                self.error(str(err))        else:            namespace, args = self._parse_known_args(args, namespace)         if hasattr(namespace, _UNRECOGNIZED_ARGS_ATTR):            args.extend(getattr(namespace, _UNRECOGNIZED_ARGS_ATTR))            delattr(namespace, _UNRECOGNIZED_ARGS_ATTR)        return namespace, args     def _parse_known_args(self, arg_strings, namespace):        # replace arg strings that are file references        if self.fromfile_prefix_chars is not None:            arg_strings = self._read_args_from_files(arg_strings)         # map all mutually exclusive arguments to the other arguments        # they can't occur with        action_conflicts = {}        for mutex_group in self._mutually_exclusive_groups:            group_actions = mutex_group._group_actions            for i, mutex_action in enumerate(mutex_group._group_actions):                conflicts = action_conflicts.setdefault(mutex_action, [])                conflicts.extend(group_actions[:i])                conflicts.extend(group_actions[i + 1:])         # find all option indices, and determine the arg_string_pattern        # which has an 'O' if there is an option at an index,        # an 'A' if there is an argument, or a '-' if there is a '--'        option_string_indices = {}        arg_string_pattern_parts = []        arg_strings_iter = iter(arg_strings)        for i, arg_string in enumerate(arg_strings_iter):             # all args after -- are non-options            if arg_string == '--':                arg_string_pattern_parts.append('-')                for arg_string in arg_strings_iter:                    arg_string_pattern_parts.append('A')             # otherwise, add the arg to the arg strings            # and note the index if it was an option            else:                option_tuple = self._parse_optional(arg_string)                if option_tuple is None:                    pattern = 'A'                else:                    option_string_indices[i] = option_tuple                    pattern = 'O'                arg_string_pattern_parts.append(pattern)         # join the pieces together to form the pattern        arg_strings_pattern = ''.join(arg_string_pattern_parts)         # converts arg strings to the appropriate and then takes the action        seen_actions = set()        seen_non_default_actions = set()         def take_action(action, argument_strings, option_string=None):            seen_actions.add(action)            argument_values = self._get_values(action, argument_strings)             # error if this argument is not allowed with other previously            # seen arguments, assuming that actions that use the default            # value don't really count as "present"            if argument_values is not action.default:                seen_non_default_actions.add(action)                for conflict_action in action_conflicts.get(action, []):                    if conflict_action in seen_non_default_actions:                        msg = _('not allowed with argument %s')                        action_name = _get_action_name(conflict_action)                        raise ArgumentError(action, msg % action_name)             # take the action if we didn't receive a SUPPRESS value            # (e.g. from a default)            if argument_values is not SUPPRESS:                action(self, namespace, argument_values, option_string)         # function to convert arg_strings into an optional action        def consume_optional(start_index):             # get the optional identified at this index            option_tuple = option_string_indices[start_index]            action, option_string, explicit_arg = option_tuple             # identify additional optionals in the same arg string            # (e.g. -xyz is the same as -x -y -z if no args are required)            match_argument = self._match_argument            action_tuples = []            while True:                 # if we found no optional action, skip it                if action is None:                    extras.append(arg_strings[start_index])                    return start_index + 1                 # if there is an explicit argument, try to match the                # optional's string arguments to only this                if explicit_arg is not None:                    arg_count = match_argument(action, 'A')                     # if the action is a single-dash option and takes no                    # arguments, try to parse more single-dash options out                    # of the tail of the option string                    chars = self.prefix_chars                    if arg_count == 0 and option_string[1] not in chars:                        action_tuples.append((action, [], option_string))                        char = option_string[0]                        option_string = char + explicit_arg[0]                        new_explicit_arg = explicit_arg[1:] or None                        optionals_map = self._option_string_actions                        if option_string in optionals_map:                            action = optionals_map[option_string]                            explicit_arg = new_explicit_arg                        else:                            msg = _('ignored explicit argument %r')                            raise ArgumentError(action, msg % explicit_arg)                     # if the action expect exactly one argument, we've                    # successfully matched the option; exit the loop                    elif arg_count == 1:                        stop = start_index + 1                        args = [explicit_arg]                        action_tuples.append((action, args, option_string))                        break                     # error if a double-dash option did not use the                    # explicit argument                    else:                        msg = _('ignored explicit argument %r')                        raise ArgumentError(action, msg % explicit_arg)                 # if there is no explicit argument, try to match the                # optional's string arguments with the following strings                # if successful, exit the loop                else:                    start = start_index + 1                    selected_patterns = arg_strings_pattern[start:]                    arg_count = match_argument(action, selected_patterns)                    stop = start + arg_count                    args = arg_strings[start:stop]                    action_tuples.append((action, args, option_string))                    break             # add the Optional to the list and return the index at which            # the Optional's string args stopped            assert action_tuples            for action, args, option_string in action_tuples:                take_action(action, args, option_string)            return stop         # the list of Positionals left to be parsed; this is modified        # by consume_positionals()        positionals = self._get_positional_actions()         # function to convert arg_strings into positional actions        def consume_positionals(start_index):            # match as many Positionals as possible            match_partial = self._match_arguments_partial            selected_pattern = arg_strings_pattern[start_index:]            arg_counts = match_partial(positionals, selected_pattern)             # slice off the appropriate arg strings for each Positional            # and add the Positional and its args to the list            for action, arg_count in zip(positionals, arg_counts):                args = arg_strings[start_index: start_index + arg_count]                start_index += arg_count                take_action(action, args)             # slice off the Positionals that we just parsed and return the            # index at which the Positionals' string args stopped            positionals[:] = positionals[len(arg_counts):]            return start_index         # consume Positionals and Optionals alternately, until we have        # passed the last option string        extras = []        start_index = 0        if option_string_indices:            max_option_string_index = max(option_string_indices)        else:            max_option_string_index = -1        while start_index <= max_option_string_index:             # consume any Positionals preceding the next option            next_option_string_index = min([                index                for index in option_string_indices                if index >= start_index])            if start_index != next_option_string_index:                positionals_end_index = consume_positionals(start_index)                 # only try to parse the next optional if we didn't consume                # the option string during the positionals parsing                if positionals_end_index > start_index:                    start_index = positionals_end_index                    continue                else:                    start_index = positionals_end_index             # if we consumed all the positionals we could and we're not            # at the index of an option string, there were extra arguments            if start_index not in option_string_indices:                strings = arg_strings[start_index:next_option_string_index]                extras.extend(strings)                start_index = next_option_string_index             # consume the next optional and any arguments for it            start_index = consume_optional(start_index)         # consume any positionals following the last Optional        stop_index = consume_positionals(start_index)         # if we didn't consume all the argument strings, there were extras        extras.extend(arg_strings[stop_index:])         # make sure all required actions were present and also convert        # action defaults which were not given as arguments        required_actions = []        for action in self._actions:            if action not in seen_actions:                if action.required:                    required_actions.append(_get_action_name(action))                else:                    # Convert action default now instead of doing it before                    # parsing arguments to avoid calling convert functions                    # twice (which may fail) if the argument was given, but                    # only if it was defined already in the namespace                    if (action.default is not None and                        isinstance(action.default, str) and                        hasattr(namespace, action.dest) and                        action.default is getattr(namespace, action.dest)):                        setattr(namespace, action.dest,                                self._get_value(action, action.default))         if required_actions:            self.error(_('the following arguments are required: %s') %                       ', '.join(required_actions))         # make sure all required groups had one option present        for group in self._mutually_exclusive_groups:            if group.required:                for action in group._group_actions:                    if action in seen_non_default_actions:                        break                 # if no actions were used, report the error                else:                    names = [_get_action_name(action)                             for action in group._group_actions                             if action.help is not SUPPRESS]                    msg = _('one of the arguments %s is required')                    self.error(msg % ' '.join(names))         # return the updated namespace and the extra arguments        return namespace, extras     def _read_args_from_files(self, arg_strings):        # expand arguments referencing files        new_arg_strings = []        for arg_string in arg_strings:             # for regular arguments, just add them back into the list            if not arg_string or arg_string[0] not in self.fromfile_prefix_chars:                new_arg_strings.append(arg_string)             # replace arguments referencing files with the file content            else:                try:                    with open(arg_string[1:]) as args_file:                        arg_strings = []                        for arg_line in args_file.read().splitlines():                            for arg in self.convert_arg_line_to_args(arg_line):                                arg_strings.append(arg)                        arg_strings = self._read_args_from_files(arg_strings)                        new_arg_strings.extend(arg_strings)                except OSError:                    err = _sys.exc_info()[1]                    self.error(str(err))         # return the modified argument list        return new_arg_strings     def convert_arg_line_to_args(self, arg_line):        return [arg_line]     def _match_argument(self, action, arg_strings_pattern):        # match the pattern for this action to the arg strings        nargs_pattern = self._get_nargs_pattern(action)        match = _re.match(nargs_pattern, arg_strings_pattern)         # raise an exception if we weren't able to find a match        if match is None:            nargs_errors = {                None: _('expected one argument'),                OPTIONAL: _('expected at most one argument'),                ONE_OR_MORE: _('expected at least one argument'),            }            msg = nargs_errors.get(action.nargs)            if msg is None:                msg = ngettext('expected %s argument',                               'expected %s arguments',                               action.nargs) % action.nargs            raise ArgumentError(action, msg)         # return the number of arguments matched        return len(match.group(1))     def _match_arguments_partial(self, actions, arg_strings_pattern):        # progressively shorten the actions list by slicing off the        # final actions until we find a match        result = []        for i in range(len(actions), 0, -1):            actions_slice = actions[:i]            pattern = ''.join([self._get_nargs_pattern(action)                               for action in actions_slice])            match = _re.match(pattern, arg_strings_pattern)            if match is not None:                result.extend([len(string) for string in match.groups()])                break         # return the list of arg string counts        return result     def _parse_optional(self, arg_string):        # if it's an empty string, it was meant to be a positional        if not arg_string:            return None         # if it doesn't start with a prefix, it was meant to be positional        if not arg_string[0] in self.prefix_chars:            return None         # if the option string is present in the parser, return the action        if arg_string in self._option_string_actions:            action = self._option_string_actions[arg_string]            return action, arg_string, None         # if it's just a single character, it was meant to be positional        if len(arg_string) == 1:            return None         # if the option string before the "=" is present, return the action        if '=' in arg_string:            option_string, explicit_arg = arg_string.split('=', 1)            if option_string in self._option_string_actions:                action = self._option_string_actions[option_string]                return action, option_string, explicit_arg         # search through all possible prefixes of the option string        # and all actions in the parser for possible interpretations        option_tuples = self._get_option_tuples(arg_string)         # if multiple actions match, the option string was ambiguous        if len(option_tuples) > 1:            options = ', '.join([option_string                for action, option_string, explicit_arg in option_tuples])            args = {'option': arg_string, 'matches': options}            msg = _('ambiguous option: %(option)s could match %(matches)s')            self.error(msg % args)         # if exactly one action matched, this segmentation is good,        # so return the parsed action        elif len(option_tuples) == 1:            option_tuple, = option_tuples            return option_tuple         # if it was not found as an option, but it looks like a negative        # number, it was meant to be positional        # unless there are negative-number-like options        if self._negative_number_matcher.match(arg_string):            if not self._has_negative_number_optionals:                return None         # if it contains a space, it was meant to be a positional        if ' ' in arg_string:            return None         # it was meant to be an optional but there is no such option        # in this parser (though it might be a valid option in a subparser)        return None, arg_string, None     def _get_option_tuples(self, option_string):        result = []         # option strings starting with two prefix characters are only        # split at the '='        chars = self.prefix_chars        if option_string[0] in chars and option_string[1] in chars:            if self.allow_abbrev:                if '=' in option_string:                    option_prefix, explicit_arg = option_string.split('=', 1)                else:                    option_prefix = option_string                    explicit_arg = None                for option_string in self._option_string_actions:                    if option_string.startswith(option_prefix):                        action = self._option_string_actions[option_string]                        tup = action, option_string, explicit_arg                        result.append(tup)         # single character options can be concatenated with their arguments        # but multiple character options always have to have their argument        # separate        elif option_string[0] in chars and option_string[1] not in chars:            option_prefix = option_string            explicit_arg = None            short_option_prefix = option_string[:2]            short_explicit_arg = option_string[2:]             for option_string in self._option_string_actions:                if option_string == short_option_prefix:                    action = self._option_string_actions[option_string]                    tup = action, option_string, short_explicit_arg                    result.append(tup)                elif option_string.startswith(option_prefix):                    action = self._option_string_actions[option_string]                    tup = action, option_string, explicit_arg                    result.append(tup)         # shouldn't ever get here        else:            self.error(_('unexpected option string: %s') % option_string)         # return the collected option tuples        return result     def _get_nargs_pattern(self, action):        # in all examples below, we have to allow for '--' args        # which are represented as '-' in the pattern        nargs = action.nargs         # the default (None) is assumed to be a single argument        if nargs is None:            nargs_pattern = '(-*A-*)'         # allow zero or one arguments        elif nargs == OPTIONAL:            nargs_pattern = '(-*A?-*)'         # allow zero or more arguments        elif nargs == ZERO_OR_MORE:            nargs_pattern = '(-*[A-]*)'         # allow one or more arguments        elif nargs == ONE_OR_MORE:            nargs_pattern = '(-*A[A-]*)'         # allow any number of options or arguments        elif nargs == REMAINDER:            nargs_pattern = '([-AO]*)'         # allow one argument followed by any number of options or arguments        elif nargs == PARSER:            nargs_pattern = '(-*A[-AO]*)'         # suppress action, like nargs=0        elif nargs == SUPPRESS:            nargs_pattern = '(-*-*)'         # all others should be integers        else:            nargs_pattern = '(-*%s-*)' % '-*'.join('A' * nargs)         # if this is an optional action, -- is not allowed        if action.option_strings:            nargs_pattern = nargs_pattern.replace('-*', '')            nargs_pattern = nargs_pattern.replace('-', '')         # return the pattern        return nargs_pattern     # ========================    # Alt command line argument parsing, allowing free intermix    # ========================     def parse_intermixed_args(self, args=None, namespace=None):        args, argv = self.parse_known_intermixed_args(args, namespace)        if argv:            msg = _('unrecognized arguments: %s')            self.error(msg % ' '.join(argv))        return args     def parse_known_intermixed_args(self, args=None, namespace=None):        # returns a namespace and list of extras        #        # positional can be freely intermixed with optionals.  optionals are        # first parsed with all positional arguments deactivated.  The 'extras'        # are then parsed.  If the parser definition is incompatible with the        # intermixed assumptions (e.g. use of REMAINDER, subparsers) a        # TypeError is raised.        #        # positionals are 'deactivated' by setting nargs and default to        # SUPPRESS.  This blocks the addition of that positional to the        # namespace         positionals = self._get_positional_actions()        a = [action for action in positionals             if action.nargs in [PARSER, REMAINDER]]        if a:            raise TypeError('parse_intermixed_args: positional arg'                            ' with nargs=%s'%a[0].nargs)         if [action.dest for group in self._mutually_exclusive_groups            for action in group._group_actions if action in positionals]:            raise TypeError('parse_intermixed_args: positional in'                            ' mutuallyExclusiveGroup')         try:            save_usage = self.usage            try:                if self.usage is None:                    # capture the full usage for use in error messages                    self.usage = self.format_usage()[7:]                for action in positionals:                    # deactivate positionals                    action.save_nargs = action.nargs                    # action.nargs = 0                    action.nargs = SUPPRESS                    action.save_default = action.default                    action.default = SUPPRESS                namespace, remaining_args = self.parse_known_args(args,                                                                  namespace)                for action in positionals:                    # remove the empty positional values from namespace                    if (hasattr(namespace, action.dest)                            and getattr(namespace, action.dest)==[]):                        from warnings import warn                        warn('Do not expect %s in %s' % (action.dest, namespace))                        delattr(namespace, action.dest)            finally:                # restore nargs and usage before exiting                for action in positionals:                    action.nargs = action.save_nargs                    action.default = action.save_default            optionals = self._get_optional_actions()            try:                # parse positionals.  optionals aren't normally required, but                # they could be, so make sure they aren't.                for action in optionals:                    action.save_required = action.required                    action.required = False                for group in self._mutually_exclusive_groups:                    group.save_required = group.required                    group.required = False                namespace, extras = self.parse_known_args(remaining_args,                                                          namespace)            finally:                # restore parser values before exiting                for action in optionals:                    action.required = action.save_required                for group in self._mutually_exclusive_groups:                    group.required = group.save_required        finally:            self.usage = save_usage        return namespace, extras     # ========================    # Value conversion methods    # ========================    def _get_values(self, action, arg_strings):        # for everything but PARSER, REMAINDER args, strip out first '--'        if action.nargs not in [PARSER, REMAINDER]:            try:                arg_strings.remove('--')            except ValueError:                pass         # optional argument produces a default when not present        if not arg_strings and action.nargs == OPTIONAL:            if action.option_strings:                value = action.const            else:                value = action.default            if isinstance(value, str):                value = self._get_value(action, value)                self._check_value(action, value)         # when nargs='*' on a positional, if there were no command-line        # args, use the default if it is anything other than None        elif (not arg_strings and action.nargs == ZERO_OR_MORE and              not action.option_strings):            if action.default is not None:                value = action.default            else:                value = arg_strings            self._check_value(action, value)         # single argument or optional argument produces a single value        elif len(arg_strings) == 1 and action.nargs in [None, OPTIONAL]:            arg_string, = arg_strings            value = self._get_value(action, arg_string)            self._check_value(action, value)         # REMAINDER arguments convert all values, checking none        elif action.nargs == REMAINDER:            value = [self._get_value(action, v) for v in arg_strings]         # PARSER arguments convert all values, but check only the first        elif action.nargs == PARSER:            value = [self._get_value(action, v) for v in arg_strings]            self._check_value(action, value[0])         # SUPPRESS argument does not put anything in the namespace        elif action.nargs == SUPPRESS:            value = SUPPRESS         # all other types of nargs produce a list        else:            value = [self._get_value(action, v) for v in arg_strings]            for v in value:                self._check_value(action, v)         # return the converted value        return value     def _get_value(self, action, arg_string):        type_func = self._registry_get('type', action.type, action.type)        if not callable(type_func):            msg = _('%r is not callable')            raise ArgumentError(action, msg % type_func)         # convert the value to the appropriate type        try:            result = type_func(arg_string)         # ArgumentTypeErrors indicate errors        except ArgumentTypeError:            name = getattr(action.type, '__name__', repr(action.type))            msg = str(_sys.exc_info()[1])            raise ArgumentError(action, msg)         # TypeErrors or ValueErrors also indicate errors        except (TypeError, ValueError):            name = getattr(action.type, '__name__', repr(action.type))            args = {'type': name, 'value': arg_string}            msg = _('invalid %(type)s value: %(value)r')            raise ArgumentError(action, msg % args)         # return the converted value        return result     def _check_value(self, action, value):        # converted value must be one of the choices (if specified)        if action.choices is not None and value not in action.choices:            args = {'value': value,                    'choices': ', '.join(map(repr, action.choices))}            msg = _('invalid choice: %(value)r (choose from %(choices)s)')            raise ArgumentError(action, msg % args)     # =======================    # Help-formatting methods    # =======================    def format_usage(self):        formatter = self._get_formatter()        formatter.add_usage(self.usage, self._actions,                            self._mutually_exclusive_groups)        return formatter.format_help()     def format_help(self):        formatter = self._get_formatter()         # usage        formatter.add_usage(self.usage, self._actions,                            self._mutually_exclusive_groups)         # description        formatter.add_text(self.description)         # positionals, optionals and user-defined groups        for action_group in self._action_groups:            formatter.start_section(action_group.title)            formatter.add_text(action_group.description)            formatter.add_arguments(action_group._group_actions)            formatter.end_section()         # epilog        formatter.add_text(self.epilog)         # determine help from format above        return formatter.format_help()     def _get_formatter(self):        return self.formatter_class(prog=self.prog)     # =====================    # Help-printing methods    # =====================    def print_usage(self, file=None):        if file is None:            file = _sys.stdout        self._print_message(self.format_usage(), file)     def print_help(self, file=None):        if file is None:            file = _sys.stdout        self._print_message(self.format_help(), file)     def _print_message(self, message, file=None):        if message:            if file is None:                file = _sys.stderr            file.write(message)     # ===============    # Exiting methods    # ===============    def exit(self, status=0, message=None):        if message:            self._print_message(message, _sys.stderr)        _sys.exit(status)     def error(self, message):        """error(message: string)         Prints a usage message incorporating the message to stderr and        exits.         If you override this in a subclass, it should not return -- it        should either exit or raise an exception.        """        self.print_usage(_sys.stderr)        args = {'prog': self.prog, 'message': message}        self.exit(2, _('%(prog)s: error: %(message)s\n') % args)