# -*- coding: utf-8 -*- # Copyright © 2006 Steven J. Bethard . # # Redistribution and use in source and binary forms, with or without # modification, are permitted under the terms of the 3-clause BSD # license. No warranty expressed or implied. # For details, see the accompanying file LICENSE.txt. """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 the command-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 -- Formatter classes which may be passed as the formatter_class= argument to the ArgumentParser constructor. HelpFormatter is the default, while RawDescriptionHelpFormatter tells the parser not to perform any line-wrapping on description text. All other classes in this module are considered implementation details. (Also note that HelpFormatter and RawDescriptionHelpFormatter are only considered public as object names -- the API of the formatter objects is still considered an implementation detail.) """ __version__ = '0.8.0' import os as _os import re as _re import sys as _sys import textwrap as _textwrap from gettext import gettext as _ SUPPRESS = '==SUPPRESS==' OPTIONAL = '?' ZERO_OR_MORE = '*' ONE_OR_MORE = '+' PARSER = '==PARSER==' # ============================= # 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 = [] for arg in self._get_args(): arg_strings.append(repr(arg)) for name, value in self._get_kwargs(): arg_strings.append('%s=%r' % (name, value)) return '%s(%s)' % (type_name, ', '.join(arg_strings)) def _get_kwargs(self): return sorted(self.__dict__.items()) def _get_args(self): return [] def _ensure_value(namespace, name, value): if getattr(namespace, name, None) is None: setattr(namespace, name, value) return getattr(namespace, name) # =============== # Formatting Help # =============== class HelpFormatter(object): def __init__(self, prog, indent_increment=2, max_help_position=24, width=None): # default setting for width if width is None: try: width = int(_os.environ['COLUMNS']) except (KeyError, ValueError): width = 80 width -= 2 self._prog = prog self._indent_increment = indent_increment self._max_help_position = max_help_position 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+') 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 for func, args in self.items: func(*args) 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, optionals, positionals, prefix=None): if usage is not SUPPRESS: args = usage, optionals, positionals, 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(len(s) for s in 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() % dict(prog=self._prog) 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, optionals, positionals, prefix): if prefix is None: prefix = _('usage: ') # if no optionals or positionals are available, usage is just prog if usage is None and not optionals and not positionals: usage = '%(prog)s' # if optionals and positionals are available, calculate usage elif usage is None: usage = '%(prog)s' % dict(prog=self._prog) # determine width of "usage: PROG" and width of text prefix_width = len(prefix) + len(usage) + 1 prefix_indent = self._current_indent + prefix_width text_width = self._width - self._current_indent # put them on one line if they're short enough format = self._format_actions_usage action_usage = format(optionals + positionals) if prefix_width + len(action_usage) + 1 < text_width: usage = '%s %s' % (usage, action_usage) # if they're long, wrap optionals and positionals individually else: optional_usage = format(optionals) positional_usage = format(positionals) indent = ' ' * prefix_indent # usage is made of PROG, optionals and positionals parts = [usage, ' '] # options always get added right after PROG if optional_usage: parts.append(_textwrap.fill( optional_usage, text_width, initial_indent=indent, subsequent_indent=indent).lstrip()) # if there were options, put arguments on the next line # otherwise, start them right after PROG if positional_usage: part = _textwrap.fill( positional_usage, text_width, initial_indent=indent, subsequent_indent=indent).lstrip() if optional_usage: part = '\n' + indent + part parts.append(part) usage = ''.join(parts) # prefix with 'usage:' return '%s%s\n\n' % (prefix, usage) def _format_actions_usage(self, actions): parts = [] for action in actions: if action.help is SUPPRESS: continue # produce all arg strings if not action.option_strings: parts.append(self._format_args(action, action.dest)) # 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 = '%s' % option_string # if the Optional takes a value, format is: # -s ARGS or --long ARGS else: default = action.dest.upper() args_string = self._format_args(action, default) part = '%s %s' % (option_string, args_string) # make it look optional if it's not required if not action.required: part = '[%s]' % part parts.append(part) return ' '.join(parts) def _format_text(self, text): text_width = self._width - self._current_indent 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 = self._width - help_position action_width = help_position - self._current_indent - 2 action_header = self._format_action_invocation(action) # ho nelp; 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: help_text = self._expand_help(action) 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: return self._format_metavar(action, action.dest) 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 = action.dest.upper() 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 _format_metavar(self, action, default_metavar): if action.metavar is not None: name = action.metavar elif action.choices is not None: choice_strs = (str(choice) for choice in action.choices) name = '{%s}' % ','.join(choice_strs) else: name = default_metavar return name def _format_args(self, action, default_metavar): name = self._format_metavar(action, default_metavar) if action.nargs is None: result = name elif action.nargs == OPTIONAL: result = '[%s]' % name elif action.nargs == ZERO_OR_MORE: result = '[%s [%s ...]]' % (name, name) elif action.nargs == ONE_OR_MORE: result = '%s [%s ...]' % (name, name) elif action.nargs is PARSER: result = '%s ...' % name else: result = ' '.join([name] * action.nargs) return result def _expand_help(self, action): params = dict(vars(action), prog=self._prog) for name, value in params.items(): if value is SUPPRESS: del params[name] if params.get('choices') is not None: choices_str = ', '.join(str(c) for c in params['choices']) params['choices'] = choices_str return action.help % params def _iter_indented_subactions(self, action): try: get_subactions = action._get_subactions except AttributeError: pass else: self._indent() for subaction in get_subactions(): yield subaction self._dedent() def _split_lines(self, text, width): text = self._whitespace_matcher.sub(' ', text).strip() return _textwrap.wrap(text, width) def _fill_text(self, text, width, indent): text = self._whitespace_matcher.sub(' ', text).strip() return _textwrap.fill(text, width, initial_indent=indent, subsequent_indent=indent) class RawDescriptionHelpFormatter(HelpFormatter): def _fill_text(self, text, width, indent): return ''.join(indent + line for line in text.splitlines(True)) class RawTextHelpFormatter(RawDescriptionHelpFormatter): def _split_lines(self, text, width): return text.splitlines() # ===================== # Options and Arguments # ===================== class ArgumentError(Exception): """ArgumentError(message, argument) Raised whenever there was an error 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): if argument.option_strings: self.argument_name = '/'.join(argument.option_strings) elif argument.metavar not in (None, SUPPRESS): self.argument_name = argument.metavar elif argument.dest not in (None, SUPPRESS): self.argument_name = argument.dest else: self.argument_name = None 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) # ============== # Action classes # ============== class Action(_AttributeHolder): """Action(*strings, **options) Action objects hold the information necessary to convert a set of command-line arguments (possibly including an initial option string) into the desired Python object(s). 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 -- The type which the command-line arguments should be converted to, should be one of 'string', 'int', 'float', 'complex' or a callable object that accepts a single string argument. If None, 'string' is assumed. 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', 'help', 'metavar' ] return [(name, getattr(self, name)) for name in names] def __call__(self, parser, namespace, values, option_string=None): raise NotImplementedError(_('.__call__() not defined')) 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 must be > 0') 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 must be > 0') 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): _ensure_value(namespace, self.dest, []).append(values) 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): _ensure_value(namespace, self.dest, []).append(self.const) 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): new_count = _ensure_value(namespace, self.dest, 0) + 1 setattr(namespace, self.dest, new_count) 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, dest=SUPPRESS, default=SUPPRESS, help=None): super(_VersionAction, 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_version() parser.exit() class _SubParsersAction(Action): class _ChoicesPseudoAction(Action): def __init__(self, name, help): sup = super(_SubParsersAction._ChoicesPseudoAction, self) sup.__init__(option_strings=[], dest=name, help=help) def __init__(self, option_strings, prog, parser_class, dest=SUPPRESS, 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, 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) # create a pseudo-action to hold the choice help if 'help' in kwargs: help = kwargs.pop('help') choice_action = self._ChoicesPseudoAction(name, 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 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: tup = parser_name, ', '.join(self._name_parser_map) msg = _('unknown parser %r (choices: %s)' % tup) raise ArgumentError(self, msg) # parse all the remaining options into the namespace parser.parse_args(arg_strings, namespace) # ============== # 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. """ def __init__(self, mode='r', bufsize=None): self._mode = mode self._bufsize = bufsize def __call__(self, string): # the special argument "-" means sys.std{in,out} if string == '-': if self._mode == 'r': return _sys.stdin elif self._mode == 'w': return _sys.stdout else: msg = _('argument "-" with mode %r' % self._mode) raise ValueError(msg) # all other arguments are used as file names if self._bufsize: return open(string, self._mode, self._bufsize) else: return open(string, self._mode) # =========================== # Optional and Positional Parsing # =========================== class Namespace(_AttributeHolder): def __init__(self, **kwargs): for name, value in kwargs.iteritems(): setattr(self, name, value) def __eq__(self, other): return vars(self) == vars(other) def __ne__(self, other): return not (self == other) 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) # raise an exception if the conflict handler is invalid self._get_handler() # action storage self._optional_actions_list = [] self._positional_actions_list = [] self._positional_actions_full_list = [] self._option_strings = {} # defaults storage self._defaults = {} # ==================== # 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 settings 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_list in [self._option_strings.values(), self._positional_actions_full_list]: for action in action_list: if action.dest in kwargs: action.default = kwargs[action.dest] # ======================= # 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: 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) action = action_class(**kwargs) return self._add_action(action) def _add_action(self, action): # resolve any conflicts self._check_conflict(action) # add to optional or positional list if action.option_strings: self._optional_actions_list.append(action) else: self._positional_actions_list.append(action) self._positional_actions_full_list.append(action) action.container = self # index the action by any option strings it has for option_string in action.option_strings: self._option_strings[option_string] = action # return the created action return action def _add_container_actions(self, container): for action in container._optional_actions_list: self._add_action(action) for action in container._positional_actions_list: 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) # 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 one-or-fewer-character option strings if len(option_string) < 2: msg = _('invalid option string %r: ' 'must be at least two characters long') raise ValueError(msg % option_string) # error on strings that don't start with an appropriate prefix if not option_string[0] in self.prefix_chars: msg = _('invalid option string %r: ' 'must start with a character %r') tup = option_string, self.prefix_chars raise ValueError(msg % tup) # error on strings that are all prefix characters if not (set(option_string) - set(self.prefix_chars)): msg = _('invalid option string %r: ' 'must contain characters other than %r') tup = option_string, self.prefix_chars raise ValueError(msg % tup) # strings starting with two prefix characters are long options option_strings.append(option_string) if option_string[0] in self.prefix_chars: if 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) 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_strings: confl_optional = self._option_strings[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 = _('conflicting option string(s): %s') 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_strings.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._optional_actions_list.remove(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) self.title = title self._registries = container._registries self._positional_actions_full_list = container._positional_actions_full_list self._option_strings = container._option_strings self._defaults = container._defaults class ArgumentParser(_AttributeHolder, _ActionsContainer): def __init__(self, prog=None, usage=None, description=None, epilog=None, version=None, parents=[], formatter_class=HelpFormatter, prefix_chars='-', argument_default=None, conflict_handler='error', add_help=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.version = version self.formatter_class = formatter_class self.add_help = add_help self._argument_group_class = _ArgumentGroup self._has_subparsers = False self._argument_groups = [] # register types def identity(string): return string self.register('type', None, identity) # add help and version arguments if necessary # (using explicit default to override global argument_default) if self.add_help: self.add_argument( '-h', '--help', action='help', default=SUPPRESS, help=_('show this help message and exit')) if self.version: self.add_argument( '-v', '--version', action='version', default=SUPPRESS, help=_("show program's version number 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) # determines whether an "option" looks like a negative number self._negative_number_matcher = _re.compile(r'^-\d+|-\d*.\d+$') # ======================= # Pretty __repr__ methods # ======================= def _get_kwargs(self): names = [ 'prog', 'usage', 'description', 'version', 'formatter_class', 'conflict_handler', 'add_help', ] return [(name, getattr(self, name)) for name in names] # ================================== # Optional/Positional adding methods # ================================== def add_argument_group(self, *args, **kwargs): group = self._argument_group_class(self, *args, **kwargs) self._argument_groups.append(group) return group def add_subparsers(self, **kwargs): if self._has_subparsers: 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)) # 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() formatter.add_usage(self.usage, [], self._get_positional_actions(), '') 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._positional_actions_list.append(action) self._positional_actions_full_list.append(action) self._has_subparsers = True # return the created parsers action return action def _add_container_actions(self, container): super(ArgumentParser, self)._add_container_actions(container) try: groups = container._argument_groups except AttributeError: pass else: for group in groups: new_group = self.add_argument_group( title=group.title, description=group.description, conflict_handler=group.conflict_handler) new_group._add_container_actions(group) def _get_optional_actions(self): actions = [] actions.extend(self._optional_actions_list) for argument_group in self._argument_groups: actions.extend(argument_group._optional_actions_list) return actions def _get_positional_actions(self): return list(self._positional_actions_full_list) # ===================================== # Command line argument parsing methods # ===================================== def parse_args(self, args=None, namespace=None): # args default to the system args if args is None: args = _sys.argv[1:] # default Namespace built from parser defaults if namespace is None: namespace = Namespace() # add any action defaults that aren't present optional_actions = self._get_optional_actions() positional_actions = self._get_positional_actions() for action in optional_actions + positional_actions: if action.dest is not SUPPRESS: if not hasattr(namespace, action.dest): if action.default is not SUPPRESS: default = action.default if isinstance(action.default, basestring): default = self._get_value(action, default) setattr(namespace, action.dest, default) # add any parser defaults that aren't present for dest, value in self._defaults.iteritems(): if not hasattr(namespace, dest): setattr(namespace, dest, value) # parse the arguments and exit if there are any errors try: result = self._parse_args(args, namespace) except ArgumentError, err: self.error(str(err)) # make sure all required optionals are present for action in self._get_optional_actions(): if action.required: if getattr(result, action.dest, None) is None: opt_strs = '/'.join(action.option_strings) msg = _('option %s is required' % opt_strs) self.error(msg) # return the parsed arguments return result def _parse_args(self, arg_strings, namespace): # 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 def take_action(action, argument_strings, option_string=None): argument_values = self._get_values(action, argument_strings) # 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): # determine the optional action and parse any explicit # argument out of the option string option_tuple = option_string_indices[start_index] action, option_string, explicit_arg = option_tuple # loop because single-dash options can be chained # (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, raise an error if action is None: self.error(_('no such option: %s') % option_string) # 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)) parse_optional = self._parse_optional for char in self.prefix_chars: option_string = char + explicit_arg option_tuple = parse_optional(option_string) if option_tuple[0] is not None: break else: msg = _('ignored explicit argument %r') raise ArgumentError(action, msg % explicit_arg) # set the action, etc. for the next loop iteration action, option_string, explicit_arg = option_tuple # 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 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 unparseable # arguments if start_index not in option_string_indices: msg = _('extra arguments found: %s') extras = arg_strings[start_index:next_option_string_index] self.error(msg % ' '.join(extras)) # 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 too # many supplied if stop_index != len(arg_strings): extras = arg_strings[stop_index:] self.error(_('extra arguments found: %s') % ' '.join(extras)) # if we didn't use all the Positional objects, there were too few # arg strings supplied. if positionals: self.error(_('too few arguments')) # return the updated namespace return namespace 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') } default = _('expected %s argument(s)') % action.nargs msg = nargs_errors.get(action.nargs, default) 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 xrange(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 doesn't start with a prefix, it was meant to be positional if not arg_string[0] in self.prefix_chars: return None # if it's just dashes, it was meant to be positional if not arg_string.strip('-'): return None # if the option string is present in the parser, return the action if arg_string in self._option_strings: action = self._option_strings[arg_string] return action, arg_string, None # search through all possible prefixes of the option string # and all actions in the parser for possible interpretations option_tuples = [] prefix_tuples = self._get_option_prefix_tuples(arg_string) for option_string in self._option_strings: for option_prefix, explicit_arg in prefix_tuples: if option_string.startswith(option_prefix): action = self._option_strings[option_string] tup = action, option_string, explicit_arg option_tuples.append(tup) break # if multiple actions match, the option string was ambiguous if len(option_tuples) > 1: options = ', '.join(opt_str for _, opt_str, _ in option_tuples) tup = arg_string, options self.error(_('ambiguous option: %s could match %s') % tup) # 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 if self._negative_number_matcher.match(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_prefix_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 '=' in option_string: option_prefix, explicit_arg = option_string.split('=', 1) else: option_prefix = option_string explicit_arg = None tup = option_prefix, explicit_arg result.append(tup) # option strings starting with a single prefix character are # split at all indices else: for first_index, char in enumerate(option_string): if char not in self.prefix_chars: break for i in xrange(len(option_string), first_index, -1): tup = option_string[:i], option_string[i:] or None result.append(tup) # return the collected prefix 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 one argument followed by any number of options or arguments elif nargs is PARSER: nargs_pattern = '(-*A[-AO]*)' # 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 # ======================== # Value conversion methods # ======================== def _get_values(self, action, arg_strings): # for everything but PARSER args, strip out '--' if action.nargs is not PARSER: arg_strings = [s for s in arg_strings if s != '--'] # 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, basestring): 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) # PARSER arguments convert all values, but check only the first elif action.nargs is PARSER: value = list(self._get_value(action, v) for v in arg_strings) self._check_value(action, value[0]) # all other types of nargs produce a list else: value = list(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) # TypeErrors or ValueErrors indicate errors except (TypeError, ValueError): name = getattr(action.type, '__name__', repr(action.type)) msg = _('invalid %s value: %r') raise ArgumentError(action, msg % (name, arg_string)) # 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: tup = value, ', '.join(map(repr, action.choices)) msg = _('invalid choice: %r (choose from %s)') % tup raise ArgumentError(action, msg) # ======================= # Help-formatting methods # ======================= def format_usage(self): formatter = self._get_formatter() formatter.add_usage(self.usage, self._get_optional_actions(), self._get_positional_actions()) return formatter.format_help() def format_help(self): formatter = self._get_formatter() # usage formatter.add_usage(self.usage, self._get_optional_actions(), self._get_positional_actions()) # description formatter.add_text(self.description) # positionals formatter.start_section(_('positional arguments')) formatter.add_arguments(self._positional_actions_list) formatter.end_section() # optionals formatter.start_section(_('optional arguments')) formatter.add_arguments(self._optional_actions_list) formatter.end_section() # user-defined groups for argument_group in self._argument_groups: formatter.start_section(argument_group.title) formatter.add_text(argument_group.description) formatter.add_arguments(argument_group._positional_actions_list) formatter.add_arguments(argument_group._optional_actions_list) formatter.end_section() # epilog formatter.add_text(self.epilog) # determine help from format above return formatter.format_help() def format_version(self): formatter = self._get_formatter() formatter.add_text(self.version) return formatter.format_help() def _get_formatter(self): return self.formatter_class(prog=self.prog) # ===================== # Help-printing methods # ===================== def print_usage(self, file=None): self._print_message(self.format_usage(), file) def print_help(self, file=None): self._print_message(self.format_help(), file) def print_version(self, file=None): self._print_message(self.format_version(), 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: _sys.stderr.write(message) _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) self.exit(2, _('%s: error: %s\n') % (self.prog, message))