"""Module adds capabilities to argparse by patching a few of its functions. It also defines a parser class called Cmd2ArgumentParser which improves error and help output over normal argparse. All cmd2 code uses this parser and it is recommended that developers of cmd2-based apps either use it or write their own parser that inherits from it. This will give a consistent look-and-feel between the help/error output of built-in cmd2 commands and the app-specific commands. If you wish to override the parser used by cmd2's built-in commands, see override_parser.py example. Since the new capabilities are added by patching at the argparse API level, they are available whether or not Cmd2ArgumentParser is used. However, the help and error output of Cmd2ArgumentParser is customized to notate nargs ranges whereas any other parser class won't be as explicit in their output. **Added capabilities** Extends argparse nargs functionality by allowing tuples which specify a range (min, max). To specify a max value with no upper bound, use a 1-item tuple (min,) Example:: # -f argument expects at least 3 values parser.add_argument('-f', nargs=(3,)) # -f argument expects 3 to 5 values parser.add_argument('-f', nargs=(3, 5)) **Tab Completion** cmd2 uses its ArgparseCompleter class to enable argparse-based tab completion on all commands that use the @with_argparse wrappers. Out of the box you get tab completion of commands, subcommands, and flag names, as well as instructive hints about the current argument that print when tab is pressed. In addition, you can add tab completion for each argument's values using parameters passed to add_argument(). Below are the 3 add_argument() parameters for enabling tab completion of an argument's value. Only one can be used at a time. ``choices`` - pass a list of values to the choices parameter. Example:: my_list = ['An Option', 'SomeOtherOption'] parser.add_argument('-o', '--options', choices=my_list) ``choices_provider`` - pass a function that returns choices. This is good in cases where the choice list is dynamically generated when the user hits tab. Example:: def my_choices_provider(self): ... return my_generated_list parser.add_argument("arg", choices_provider=my_choices_provider) ``completer`` - pass a tab completion function that does custom completion. cmd2 provides a few completer methods for convenience (e.g., path_complete, delimiter_complete) Example:: # This adds file-path completion to an argument parser.add_argument('-o', '--options', completer=cmd2.Cmd.path_complete) You can use functools.partial() to prepopulate values of the underlying choices and completer functions/methods. Example:: # This says to call path_complete with a preset value for its path_filter argument dir_completer = functools.partial(path_complete, path_filter=lambda path: os.path.isdir(path)) parser.add_argument('-o', '--options', completer=dir_completer) For ``choices_provider`` and ``completer``, do not set them to a bound method. This is because ArgparseCompleter passes the `self` argument explicitly to these functions. When ArgparseCompleter calls one, it will detect whether it is bound to a `Cmd` subclass or `CommandSet`. If bound to a `cmd2.Cmd subclass`, it will pass the app instance as the `self` argument. If bound to a `cmd2.CommandSet` subclass, it will pass the `CommandSet` instance as the `self` argument. Therefore instead of passing something like `self.path_complete`, pass `cmd2.Cmd.path_complete`. ``choices_provider`` and ``completer`` functions can also be implemented as standalone functions (i.e. not a member of a class). In this case, ArgparseCompleter will pass its ``cmd2.Cmd`` app instance as the first positional argument. Of the 3 tab completion parameters, ``choices`` is the only one where argparse validates user input against items in the choices list. This is because the other 2 parameters are meant to tab complete data sets that are viewed as dynamic. Therefore it is up to the developer to validate if the user has typed an acceptable value for these arguments. There are times when what's being tab completed is determined by a previous argument on the command line. In these cases, ArgparseCompleter can pass a dictionary that maps the command line tokens up through the one being completed to their argparse argument name. To receive this dictionary, your choices/completer function should have an argument called arg_tokens. Example:: def my_choices_provider(self, arg_tokens) def my_completer(self, text, line, begidx, endidx, arg_tokens) All values of the arg_tokens dictionary are lists, even if a particular argument expects only 1 token. Since ArgparseCompleter is for tab completion, it does not convert the tokens to their actual argument types or validate their values. All tokens are stored in the dictionary as the raw strings provided on the command line. It is up to the developer to determine if the user entered the correct argument type (e.g. int) and validate their values. CompletionItem Class - This class was added to help in cases where uninformative data is being tab completed. For instance, tab completing ID numbers isn't very helpful to a user without context. Returning a list of CompletionItems instead of a regular string for completion results will signal the ArgparseCompleter to output the completion results in a table of completion tokens with descriptions instead of just a table of tokens:: Instead of this: 1 2 3 The user sees this: ITEM_ID Item Name ============================ 1 My item 2 Another item 3 Yet another item The left-most column is the actual value being tab completed and its header is that value's name. The right column header is defined using the descriptive_header parameter of add_argument(). The right column values come from the CompletionItem.description value. Example:: token = 1 token_description = "My Item" completion_item = CompletionItem(token, token_description) Since descriptive_header and CompletionItem.description are just strings, you can format them in such a way to have multiple columns:: ITEM_ID Item Name Checked Out Due Date ========================================================== 1 My item True 02/02/2022 2 Another item False 3 Yet another item False To use CompletionItems, just return them from your choices_provider or completer functions. They can also be used as argparse choices. When a CompletionItem is created, it stores the original value (e.g. ID number) and makes it accessible through a property called orig_value. cmd2 has patched argparse so that when evaluating choices, input is compared to CompletionItem.orig_value instead of the CompletionItem instance. To avoid printing a ton of information to the screen at once when a user presses tab, there is a maximum threshold for the number of CompletionItems that will be shown. Its value is defined in cmd2.Cmd.max_completion_items. It defaults to 50, but can be changed. If the number of completion suggestions exceeds this number, they will be displayed in the typical columnized format and will not include the description value of the CompletionItems. **Patched argparse functions** ``argparse._ActionsContainer.add_argument`` - adds arguments related to tab completion and enables nargs range parsing. See _add_argument_wrapper for more details on these arguments. ``argparse.ArgumentParser._check_value`` - adds support for using ``CompletionItems`` as argparse choices. When evaluating choices, input is compared to ``CompletionItem.orig_value`` instead of the ``CompletionItem`` instance. See _ArgumentParser_check_value for more details. ``argparse.ArgumentParser._get_nargs_pattern`` - adds support for nargs ranges. See _get_nargs_pattern_wrapper for more details. ``argparse.ArgumentParser._match_argument`` - adds support for nargs ranges. See _match_argument_wrapper for more details. ``argparse._SubParsersAction.remove_parser`` - new function which removes a sub-parser from a sub-parsers group. See _SubParsersAction_remove_parser for more details. **Added accessor methods** cmd2 has patched ``argparse.Action`` to include the following accessor methods for cases in which you need to manually access the cmd2-specific attributes. - ``argparse.Action.get_choices_callable()`` - See `action_get_choices_callable` for more details. - ``argparse.Action.set_choices_provider()`` - See `_action_set_choices_provider` for more details. - ``argparse.Action.set_completer()`` - See `_action_set_completer` for more details. - ``argparse.Action.get_descriptive_header()`` - See `_action_get_descriptive_header` for more details. - ``argparse.Action.set_descriptive_header()`` - See `_action_set_descriptive_header` for more details. - ``argparse.Action.get_nargs_range()`` - See `_action_get_nargs_range` for more details. - ``argparse.Action.set_nargs_range()`` - See `_action_set_nargs_range` for more details. - ``argparse.Action.get_suppress_tab_hint()`` - See `_action_get_suppress_tab_hint` for more details. - ``argparse.Action.set_suppress_tab_hint()`` - See `_action_set_suppress_tab_hint` for more details. cmd2 has patched ``argparse.ArgumentParser`` to include the following accessor methods - ``argparse.ArgumentParser.get_ap_completer_type()`` - See `_ArgumentParser_get_ap_completer_type` for more details. - ``argparse.Action.set_ap_completer_type()`` - See `_ArgumentParser_set_ap_completer_type` for more details. **Subcommand removal** cmd2 has patched ``argparse._SubParsersAction`` to include a ``remove_parser()`` method which can be used to remove a subcommand. ``argparse._SubParsersAction.remove_parser`` - new function which removes a sub-parser from a sub-parsers group. See _SubParsersAction_remove_parser` for more details. """ import argparse import re import sys from argparse import ( ONE_OR_MORE, ZERO_OR_MORE, ArgumentError, ) from collections.abc import ( Callable, Iterable, Sequence, ) from gettext import gettext from typing import ( IO, TYPE_CHECKING, Any, ClassVar, NoReturn, Optional, Protocol, Union, cast, runtime_checkable, ) from rich_argparse import RawTextRichHelpFormatter from . import ( ansi, constants, ) if TYPE_CHECKING: # pragma: no cover from .argparse_completer import ( ArgparseCompleter, ) def generate_range_error(range_min: int, range_max: float) -> str: """Generate an error message when the the number of arguments provided is not within the expected range.""" err_str = "expected " if range_max == constants.INFINITY: plural = '' if range_min == 1 else 's' err_str += f"at least {range_min}" else: plural = '' if range_max == 1 else 's' if range_min == range_max: err_str += f"{range_min}" else: err_str += f"{range_min} to {range_max}" err_str += f" argument{plural}" return err_str class CompletionItem(str): # noqa: SLOT000 """Completion item with descriptive text attached. See header of this file for more information """ def __new__(cls, value: object, *_args: Any, **_kwargs: Any) -> 'CompletionItem': """Responsible for creating and returning a new instance, called before __init__ when an object is instantiated.""" return super().__new__(cls, value) def __init__(self, value: object, description: str = '', *args: Any) -> None: """CompletionItem Initializer. :param value: the value being tab completed :param description: description text to display :param args: args for str __init__ """ super().__init__(*args) self.description = description # Save the original value to support CompletionItems as argparse choices. # cmd2 has patched argparse so input is compared to this value instead of the CompletionItem instance. self._orig_value = value @property def orig_value(self) -> Any: """Read-only property for _orig_value.""" return self._orig_value ############################################################################################################ # Class and functions related to ChoicesCallable ############################################################################################################ @runtime_checkable class ChoicesProviderFuncBase(Protocol): """Function that returns a list of choices in support of tab completion.""" def __call__(self) -> list[str]: # pragma: no cover """Enable instances to be called like functions.""" @runtime_checkable class ChoicesProviderFuncWithTokens(Protocol): """Function that returns a list of choices in support of tab completion and accepts a dictionary of prior arguments.""" def __call__(self, *, arg_tokens: dict[str, list[str]] = {}) -> list[str]: # pragma: no cover # noqa: B006 """Enable instances to be called like functions.""" ChoicesProviderFunc = Union[ChoicesProviderFuncBase, ChoicesProviderFuncWithTokens] @runtime_checkable class CompleterFuncBase(Protocol): """Function to support tab completion with the provided state of the user prompt.""" def __call__( self, text: str, line: str, begidx: int, endidx: int, ) -> list[str]: # pragma: no cover """Enable instances to be called like functions.""" @runtime_checkable class CompleterFuncWithTokens(Protocol): """Function to support tab completion with the provided state of the user prompt, accepts a dictionary of prior args.""" def __call__( self, text: str, line: str, begidx: int, endidx: int, *, arg_tokens: dict[str, list[str]] = {}, # noqa: B006 ) -> list[str]: # pragma: no cover """Enable instances to be called like functions.""" CompleterFunc = Union[CompleterFuncBase, CompleterFuncWithTokens] class ChoicesCallable: """Enables using a callable as the choices provider for an argparse argument. While argparse has the built-in choices attribute, it is limited to an iterable. """ def __init__( self, is_completer: bool, to_call: Union[CompleterFunc, ChoicesProviderFunc], ) -> None: """Initialize the ChoiceCallable instance. :param is_completer: True if to_call is a tab completion routine which expects the args: text, line, begidx, endidx :param to_call: the callable object that will be called to provide choices for the argument. """ self.is_completer = is_completer if is_completer: if not isinstance(to_call, (CompleterFuncBase, CompleterFuncWithTokens)): # pragma: no cover # runtime checking of Protocols do not currently check the parameters of a function. raise ValueError( 'With is_completer set to true, to_call must be either CompleterFunc, CompleterFuncWithTokens' ) elif not isinstance(to_call, (ChoicesProviderFuncBase, ChoicesProviderFuncWithTokens)): # pragma: no cover # runtime checking of Protocols do not currently check the parameters of a function. raise ValueError( 'With is_completer set to false, to_call must be either: ' 'ChoicesProviderFuncBase, ChoicesProviderFuncWithTokens' ) self.to_call = to_call @property def completer(self) -> CompleterFunc: """Retreive the internal Completer function, first type checking to ensure it is the right type.""" if not isinstance(self.to_call, (CompleterFuncBase, CompleterFuncWithTokens)): # pragma: no cover # this should've been caught in the constructor, just a backup check raise TypeError('Function is not a CompleterFunc') return self.to_call @property def choices_provider(self) -> ChoicesProviderFunc: """Retreive the internal ChoicesProvider function, first type checking to ensure it is the right type.""" if not isinstance(self.to_call, (ChoicesProviderFuncBase, ChoicesProviderFuncWithTokens)): # pragma: no cover # this should've been caught in the constructor, just a backup check raise TypeError('Function is not a ChoicesProviderFunc') return self.to_call ############################################################################################################ # The following are names of custom argparse Action attributes added by cmd2 ############################################################################################################ # ChoicesCallable object that specifies the function to be called which provides choices to the argument ATTR_CHOICES_CALLABLE = 'choices_callable' # Descriptive header that prints when using CompletionItems ATTR_DESCRIPTIVE_HEADER = 'descriptive_header' # A tuple specifying nargs as a range (min, max) ATTR_NARGS_RANGE = 'nargs_range' # Pressing tab normally displays the help text for the argument if no choices are available # Setting this attribute to True will suppress these hints ATTR_SUPPRESS_TAB_HINT = 'suppress_tab_hint' ############################################################################################################ # Patch argparse.Action with accessors for choice_callable attribute ############################################################################################################ def _action_get_choices_callable(self: argparse.Action) -> Optional[ChoicesCallable]: """Get the choices_callable attribute of an argparse Action. This function is added by cmd2 as a method called ``get_choices_callable()`` to ``argparse.Action`` class. To call: ``action.get_choices_callable()`` :param self: argparse Action being queried :return: A ChoicesCallable instance or None if attribute does not exist """ return cast(Optional[ChoicesCallable], getattr(self, ATTR_CHOICES_CALLABLE, None)) setattr(argparse.Action, 'get_choices_callable', _action_get_choices_callable) def _action_set_choices_callable(self: argparse.Action, choices_callable: ChoicesCallable) -> None: """Set the choices_callable attribute of an argparse Action. This function is added by cmd2 as a method called ``_set_choices_callable()`` to ``argparse.Action`` class. Call this using the convenience wrappers ``set_choices_provider()`` and ``set_completer()`` instead. :param self: action being edited :param choices_callable: the ChoicesCallable instance to use :raises TypeError: if used on incompatible action type """ # Verify consistent use of parameters if self.choices is not None: err_msg = "None of the following parameters can be used alongside a choices parameter:\nchoices_provider, completer" raise (TypeError(err_msg)) if self.nargs == 0: err_msg = ( "None of the following parameters can be used on an action that takes no arguments:\nchoices_provider, completer" ) raise (TypeError(err_msg)) setattr(self, ATTR_CHOICES_CALLABLE, choices_callable) setattr(argparse.Action, '_set_choices_callable', _action_set_choices_callable) def _action_set_choices_provider( self: argparse.Action, choices_provider: ChoicesProviderFunc, ) -> None: """Set choices_provider of an argparse Action. This function is added by cmd2 as a method called ``set_choices_callable()`` to ``argparse.Action`` class. To call: ``action.set_choices_provider(choices_provider)`` :param self: action being edited :param choices_provider: the choices_provider instance to use :raises TypeError: if used on incompatible action type """ self._set_choices_callable(ChoicesCallable(is_completer=False, to_call=choices_provider)) # type: ignore[attr-defined] setattr(argparse.Action, 'set_choices_provider', _action_set_choices_provider) def _action_set_completer( self: argparse.Action, completer: CompleterFunc, ) -> None: """Set completer of an argparse Action. This function is added by cmd2 as a method called ``set_completer()`` to ``argparse.Action`` class. To call: ``action.set_completer(completer)`` :param self: action being edited :param completer: the completer instance to use :raises TypeError: if used on incompatible action type """ self._set_choices_callable(ChoicesCallable(is_completer=True, to_call=completer)) # type: ignore[attr-defined] setattr(argparse.Action, 'set_completer', _action_set_completer) ############################################################################################################ # Patch argparse.Action with accessors for descriptive_header attribute ############################################################################################################ def _action_get_descriptive_header(self: argparse.Action) -> Optional[str]: """Get the descriptive_header attribute of an argparse Action. This function is added by cmd2 as a method called ``get_descriptive_header()`` to ``argparse.Action`` class. To call: ``action.get_descriptive_header()`` :param self: argparse Action being queried :return: The value of descriptive_header or None if attribute does not exist """ return cast(Optional[str], getattr(self, ATTR_DESCRIPTIVE_HEADER, None)) setattr(argparse.Action, 'get_descriptive_header', _action_get_descriptive_header) def _action_set_descriptive_header(self: argparse.Action, descriptive_header: Optional[str]) -> None: """Set the descriptive_header attribute of an argparse Action. This function is added by cmd2 as a method called ``set_descriptive_header()`` to ``argparse.Action`` class. To call: ``action.set_descriptive_header(descriptive_header)`` :param self: argparse Action being updated :param descriptive_header: value being assigned """ setattr(self, ATTR_DESCRIPTIVE_HEADER, descriptive_header) setattr(argparse.Action, 'set_descriptive_header', _action_set_descriptive_header) ############################################################################################################ # Patch argparse.Action with accessors for nargs_range attribute ############################################################################################################ def _action_get_nargs_range(self: argparse.Action) -> Optional[tuple[int, Union[int, float]]]: """Get the nargs_range attribute of an argparse Action. This function is added by cmd2 as a method called ``get_nargs_range()`` to ``argparse.Action`` class. To call: ``action.get_nargs_range()`` :param self: argparse Action being queried :return: The value of nargs_range or None if attribute does not exist """ return cast(Optional[tuple[int, Union[int, float]]], getattr(self, ATTR_NARGS_RANGE, None)) setattr(argparse.Action, 'get_nargs_range', _action_get_nargs_range) def _action_set_nargs_range(self: argparse.Action, nargs_range: Optional[tuple[int, Union[int, float]]]) -> None: """Set the nargs_range attribute of an argparse Action. This function is added by cmd2 as a method called ``set_nargs_range()`` to ``argparse.Action`` class. To call: ``action.set_nargs_range(nargs_range)`` :param self: argparse Action being updated :param nargs_range: value being assigned """ setattr(self, ATTR_NARGS_RANGE, nargs_range) setattr(argparse.Action, 'set_nargs_range', _action_set_nargs_range) ############################################################################################################ # Patch argparse.Action with accessors for suppress_tab_hint attribute ############################################################################################################ def _action_get_suppress_tab_hint(self: argparse.Action) -> bool: """Get the suppress_tab_hint attribute of an argparse Action. This function is added by cmd2 as a method called ``get_suppress_tab_hint()`` to ``argparse.Action`` class. To call: ``action.get_suppress_tab_hint()`` :param self: argparse Action being queried :return: The value of suppress_tab_hint or False if attribute does not exist """ return cast(bool, getattr(self, ATTR_SUPPRESS_TAB_HINT, False)) setattr(argparse.Action, 'get_suppress_tab_hint', _action_get_suppress_tab_hint) def _action_set_suppress_tab_hint(self: argparse.Action, suppress_tab_hint: bool) -> None: """Set the suppress_tab_hint attribute of an argparse Action. This function is added by cmd2 as a method called ``set_suppress_tab_hint()`` to ``argparse.Action`` class. To call: ``action.set_suppress_tab_hint(suppress_tab_hint)`` :param self: argparse Action being updated :param suppress_tab_hint: value being assigned """ setattr(self, ATTR_SUPPRESS_TAB_HINT, suppress_tab_hint) setattr(argparse.Action, 'set_suppress_tab_hint', _action_set_suppress_tab_hint) ############################################################################################################ # Allow developers to add custom action attributes ############################################################################################################ CUSTOM_ACTION_ATTRIBS: set[str] = set() _CUSTOM_ATTRIB_PFX = '_attr_' def register_argparse_argument_parameter(param_name: str, param_type: Optional[type[Any]]) -> None: """Register a custom argparse argument parameter. The registered name will then be a recognized keyword parameter to the parser's `add_argument()` function. An accessor functions will be added to the parameter's Action object in the form of: ``get_{param_name}()`` and ``set_{param_name}(value)``. :param param_name: Name of the parameter to add. :param param_type: Type of the parameter to add. """ attr_name = f'{_CUSTOM_ATTRIB_PFX}{param_name}' if param_name in CUSTOM_ACTION_ATTRIBS or hasattr(argparse.Action, attr_name): raise KeyError(f'Custom parameter {param_name} already exists') if not re.search('^[A-Za-z_][A-Za-z0-9_]*$', param_name): raise KeyError(f'Invalid parameter name {param_name} - cannot be used as a python identifier') getter_name = f'get_{param_name}' def _action_get_custom_parameter(self: argparse.Action) -> Any: """Get the custom attribute of an argparse Action. This function is added by cmd2 as a method called ``get_()`` to ``argparse.Action`` class. To call: ``action.get_()`` :param self: argparse Action being queried :return: The value of the custom attribute or None if attribute does not exist """ return getattr(self, attr_name, None) setattr(argparse.Action, getter_name, _action_get_custom_parameter) setter_name = f'set_{param_name}' def _action_set_custom_parameter(self: argparse.Action, value: Any) -> None: """Set the custom attribute of an argparse Action. This function is added by cmd2 as a method called ``set_()`` to ``argparse.Action`` class. To call: ``action.set_()`` :param self: argparse Action being updated :param value: value being assigned """ if param_type and not isinstance(value, param_type): raise TypeError(f'{param_name} must be of type {param_type}, got: {value} ({type(value)})') setattr(self, attr_name, value) setattr(argparse.Action, setter_name, _action_set_custom_parameter) CUSTOM_ACTION_ATTRIBS.add(param_name) ############################################################################################################ # Patch _ActionsContainer.add_argument with our wrapper to support more arguments ############################################################################################################ # Save original _ActionsContainer.add_argument so we can call it in our wrapper orig_actions_container_add_argument = argparse._ActionsContainer.add_argument def _add_argument_wrapper( self: argparse._ActionsContainer, *args: Any, nargs: Union[int, str, tuple[int], tuple[int, int], tuple[int, float], None] = None, choices_provider: Optional[ChoicesProviderFunc] = None, completer: Optional[CompleterFunc] = None, suppress_tab_hint: bool = False, descriptive_header: Optional[str] = None, **kwargs: Any, ) -> argparse.Action: """Wrap ActionsContainer.add_argument() which supports more settings used by cmd2. # Args from original function :param self: instance of the _ActionsContainer being added to :param args: arguments expected by argparse._ActionsContainer.add_argument # Customized arguments from original function :param nargs: extends argparse nargs functionality by allowing tuples which specify a range (min, max) to specify a max value with no upper bound, use a 1-item tuple (min,) # Added args used by ArgparseCompleter :param choices_provider: function that provides choices for this argument :param completer: tab completion function that provides choices for this argument :param suppress_tab_hint: when ArgparseCompleter has no results to show during tab completion, it displays the current argument's help text as a hint. Set this to True to suppress the hint. If this argument's help text is set to argparse.SUPPRESS, then tab hints will not display regardless of the value passed for suppress_tab_hint. Defaults to False. :param descriptive_header: if the provided choices are CompletionItems, then this header will display during tab completion. Defaults to None. # Args from original function :param kwargs: keyword-arguments recognized by argparse._ActionsContainer.add_argument Note: You can only use 1 of the following in your argument: choices, choices_provider, completer See the header of this file for more information :return: the created argument action :raises ValueError: on incorrect parameter usage """ # Verify consistent use of arguments choices_callables = [choices_provider, completer] num_params_set = len(choices_callables) - choices_callables.count(None) if num_params_set > 1: err_msg = "Only one of the following parameters may be used at a time:\nchoices_provider, completer" raise (ValueError(err_msg)) # Pre-process special ranged nargs nargs_range = None if nargs is not None: nargs_adjusted: Union[int, str, tuple[int], tuple[int, int], tuple[int, float], None] # Check if nargs was given as a range if isinstance(nargs, tuple): # Handle 1-item tuple by setting max to INFINITY if len(nargs) == 1: nargs = (nargs[0], constants.INFINITY) # Validate nargs tuple if ( len(nargs) != 2 or not isinstance(nargs[0], int) # type: ignore[unreachable] or not (isinstance(nargs[1], int) or nargs[1] == constants.INFINITY) # type: ignore[misc] ): raise ValueError('Ranged values for nargs must be a tuple of 1 or 2 integers') if nargs[0] >= nargs[1]: # type: ignore[misc] raise ValueError('Invalid nargs range. The first value must be less than the second') if nargs[0] < 0: raise ValueError('Negative numbers are invalid for nargs range') # Save the nargs tuple as our range setting nargs_range = nargs range_min = nargs_range[0] range_max = nargs_range[1] # type: ignore[misc] # Convert nargs into a format argparse recognizes if range_min == 0: if range_max == 1: nargs_adjusted = argparse.OPTIONAL # No range needed since (0, 1) is just argparse.OPTIONAL nargs_range = None else: nargs_adjusted = argparse.ZERO_OR_MORE if range_max == constants.INFINITY: # No range needed since (0, INFINITY) is just argparse.ZERO_OR_MORE nargs_range = None elif range_min == 1 and range_max == constants.INFINITY: nargs_adjusted = argparse.ONE_OR_MORE # No range needed since (1, INFINITY) is just argparse.ONE_OR_MORE nargs_range = None else: nargs_adjusted = argparse.ONE_OR_MORE else: nargs_adjusted = nargs # Add the argparse-recognized version of nargs to kwargs kwargs['nargs'] = nargs_adjusted # Extract registered custom keyword arguments custom_attribs = {keyword: value for keyword, value in kwargs.items() if keyword in CUSTOM_ACTION_ATTRIBS} for keyword in custom_attribs: del kwargs[keyword] # Create the argument using the original add_argument function new_arg = orig_actions_container_add_argument(self, *args, **kwargs) # Set the custom attributes new_arg.set_nargs_range(nargs_range) # type: ignore[arg-type, attr-defined] if choices_provider: new_arg.set_choices_provider(choices_provider) # type: ignore[attr-defined] elif completer: new_arg.set_completer(completer) # type: ignore[attr-defined] new_arg.set_suppress_tab_hint(suppress_tab_hint) # type: ignore[attr-defined] new_arg.set_descriptive_header(descriptive_header) # type: ignore[attr-defined] for keyword, value in custom_attribs.items(): attr_setter = getattr(new_arg, f'set_{keyword}', None) if attr_setter is not None: attr_setter(value) return new_arg # Overwrite _ActionsContainer.add_argument with our wrapper setattr(argparse._ActionsContainer, 'add_argument', _add_argument_wrapper) ############################################################################################################ # Patch ArgumentParser._get_nargs_pattern with our wrapper to support nargs ranges ############################################################################################################ # Save original ArgumentParser._get_nargs_pattern so we can call it in our wrapper orig_argument_parser_get_nargs_pattern = argparse.ArgumentParser._get_nargs_pattern def _get_nargs_pattern_wrapper(self: argparse.ArgumentParser, action: argparse.Action) -> str: # Wrapper around ArgumentParser._get_nargs_pattern behavior to support nargs ranges nargs_range = action.get_nargs_range() # type: ignore[attr-defined] if nargs_range: range_max = '' if nargs_range[1] == constants.INFINITY else nargs_range[1] nargs_pattern = f'(-*A{{{nargs_range[0]},{range_max}}}-*)' # if this is an optional action, -- is not allowed if action.option_strings: nargs_pattern = nargs_pattern.replace('-*', '') nargs_pattern = nargs_pattern.replace('-', '') return nargs_pattern return orig_argument_parser_get_nargs_pattern(self, action) # Overwrite ArgumentParser._get_nargs_pattern with our wrapper setattr(argparse.ArgumentParser, '_get_nargs_pattern', _get_nargs_pattern_wrapper) ############################################################################################################ # Patch ArgumentParser._match_argument with our wrapper to support nargs ranges ############################################################################################################ orig_argument_parser_match_argument = argparse.ArgumentParser._match_argument def _match_argument_wrapper(self: argparse.ArgumentParser, action: argparse.Action, arg_strings_pattern: str) -> int: # Wrapper around ArgumentParser._match_argument behavior to support nargs ranges 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_range = action.get_nargs_range() # type: ignore[attr-defined] if nargs_range is not None: raise ArgumentError(action, generate_range_error(nargs_range[0], nargs_range[1])) return orig_argument_parser_match_argument(self, action, arg_strings_pattern) # Overwrite ArgumentParser._match_argument with our wrapper setattr(argparse.ArgumentParser, '_match_argument', _match_argument_wrapper) ############################################################################################################ # Patch argparse.ArgumentParser with accessors for ap_completer_type attribute ############################################################################################################ # An ArgumentParser attribute which specifies a subclass of ArgparseCompleter for custom tab completion behavior on a # given parser. If this is None or not present, then cmd2 will use argparse_completer.DEFAULT_AP_COMPLETER when tab # completing a parser's arguments ATTR_AP_COMPLETER_TYPE = 'ap_completer_type' def _ArgumentParser_get_ap_completer_type(self: argparse.ArgumentParser) -> Optional[type['ArgparseCompleter']]: # noqa: N802 """Get the ap_completer_type attribute of an argparse ArgumentParser. This function is added by cmd2 as a method called ``get_ap_completer_type()`` to ``argparse.ArgumentParser`` class. To call: ``parser.get_ap_completer_type()`` :param self: ArgumentParser being queried :return: An ArgparseCompleter-based class or None if attribute does not exist """ return cast(Optional[type['ArgparseCompleter']], getattr(self, ATTR_AP_COMPLETER_TYPE, None)) setattr(argparse.ArgumentParser, 'get_ap_completer_type', _ArgumentParser_get_ap_completer_type) def _ArgumentParser_set_ap_completer_type(self: argparse.ArgumentParser, ap_completer_type: type['ArgparseCompleter']) -> None: # noqa: N802 """Set the ap_completer_type attribute of an argparse ArgumentParser. This function is added by cmd2 as a method called ``set_ap_completer_type()`` to ``argparse.ArgumentParser`` class. To call: ``parser.set_ap_completer_type(ap_completer_type)`` :param self: ArgumentParser being edited :param ap_completer_type: the custom ArgparseCompleter-based class to use when tab completing arguments for this parser """ setattr(self, ATTR_AP_COMPLETER_TYPE, ap_completer_type) setattr(argparse.ArgumentParser, 'set_ap_completer_type', _ArgumentParser_set_ap_completer_type) ############################################################################################################ # Patch ArgumentParser._check_value to support CompletionItems as choices ############################################################################################################ def _ArgumentParser_check_value(_self: argparse.ArgumentParser, action: argparse.Action, value: Any) -> None: # noqa: N802 """Check_value that supports CompletionItems as choices (Custom override of ArgumentParser._check_value). When evaluating choices, input is compared to CompletionItem.orig_value instead of the CompletionItem instance. :param self: ArgumentParser instance :param action: the action being populated :param value: value from command line already run through conversion function by argparse """ # Import gettext like argparse does from gettext import ( gettext as _, ) # converted value must be one of the choices (if specified) if action.choices is not None: # If any choice is a CompletionItem, then use its orig_value property. choices = [c.orig_value if isinstance(c, CompletionItem) else c for c in action.choices] if value not in choices: args = {'value': value, 'choices': ', '.join(map(repr, choices))} msg = _('invalid choice: %(value)r (choose from %(choices)s)') raise ArgumentError(action, msg % args) setattr(argparse.ArgumentParser, '_check_value', _ArgumentParser_check_value) ############################################################################################################ # Patch argparse._SubParsersAction to add remove_parser function ############################################################################################################ def _SubParsersAction_remove_parser(self: argparse._SubParsersAction, name: str) -> None: # type: ignore[type-arg] # noqa: N802 """Remove a sub-parser from a sub-parsers group. Used to remove subcommands from a parser. This function is added by cmd2 as a method called ``remove_parser()`` to ``argparse._SubParsersAction`` class. To call: ``action.remove_parser(name)`` :param self: instance of the _SubParsersAction being edited :param name: name of the subcommand for the sub-parser to remove """ # Remove this subcommand from its base command's help text for choice_action in self._choices_actions: if choice_action.dest == name: self._choices_actions.remove(choice_action) break # Remove this subcommand and all its aliases from the base command subparser = self._name_parser_map.get(name) if subparser is not None: to_remove = [] for cur_name, cur_parser in self._name_parser_map.items(): if cur_parser is subparser: to_remove.append(cur_name) for cur_name in to_remove: del self._name_parser_map[cur_name] setattr(argparse._SubParsersAction, 'remove_parser', _SubParsersAction_remove_parser) ############################################################################################################ # Unless otherwise noted, everything below this point are copied from Python's # argparse implementation with minor tweaks to adjust output. # Changes are noted if it's buried in a block of copied code. Otherwise the # function will check for a special case and fall back to the parent function ############################################################################################################ class Cmd2HelpFormatter(RawTextRichHelpFormatter): """Custom help formatter to configure ordering of help text.""" # rich-argparse formats all group names with str.title(). # Override their formatter to do nothing. group_name_formatter: ClassVar[Callable[[str], str]] = str # Disable automatic highlighting in the help text. highlights: ClassVar[list[str]] = [] # Disable markup rendering in usage, help, description, and epilog text. # cmd2's built-in commands do not escape opening brackets in their help text # and therefore rely on these settings being False. If you desire to use # markup in your help text, inherit from Cmd2HelpFormatter and override # these settings in that child class. usage_markup: ClassVar[bool] = False help_markup: ClassVar[bool] = False text_markup: ClassVar[bool] = False def _format_usage( self, usage: Optional[str], actions: Iterable[argparse.Action], groups: Iterable[argparse._ArgumentGroup], prefix: Optional[str] = None, ) -> str: if prefix is None: prefix = gettext('Usage: ') # if usage is specified, use that if usage is not None: usage %= {"prog": self._prog} # if no optionals or positionals are available, usage is just prog elif not actions: usage = f'{self._prog}' # if optionals and positionals are available, calculate usage else: prog = f'{self._prog}' # split optionals from positionals optionals = [] positionals = [] # Begin cmd2 customization (separates required and optional, applies to all changes in this function) required_options = [] for action in actions: if action.option_strings: if action.required: required_options.append(action) else: optionals.append(action) else: positionals.append(action) # End cmd2 customization # build full usage string format_actions = self._format_actions_usage action_usage = format_actions(required_options + optionals + positionals, groups) # type: ignore[arg-type] 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: # Begin cmd2 customization # break usage into wrappable parts part_regexp = r'\(.*?\)+|\[.*?\]+|\S+' req_usage = format_actions(required_options, groups) # type: ignore[arg-type] opt_usage = format_actions(optionals, groups) # type: ignore[arg-type] pos_usage = format_actions(positionals, groups) # type: ignore[arg-type] req_parts = re.findall(part_regexp, req_usage) opt_parts = re.findall(part_regexp, opt_usage) pos_parts = re.findall(part_regexp, pos_usage) # End cmd2 customization # helper for wrapping lines def get_lines(parts: list[str], indent: str, prefix: Optional[str] = None) -> list[str]: lines: list[str] = [] line: list[str] = [] line_len = len(prefix) - 1 if prefix is not None else 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) # Begin cmd2 customization if req_parts: lines = get_lines([prog, *req_parts], indent, prefix) lines.extend(get_lines(opt_parts, indent)) lines.extend(get_lines(pos_parts, indent)) elif 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] # End cmd2 customization # if prog is long, put it on its own line else: indent = ' ' * len(prefix) # Begin cmd2 customization parts = req_parts + opt_parts + pos_parts lines = get_lines(parts, indent) if len(lines) > 1: lines = [] lines.extend(get_lines(req_parts, indent)) lines.extend(get_lines(opt_parts, indent)) lines.extend(get_lines(pos_parts, indent)) # End cmd2 customization lines = [prog, *lines] # join lines into usage usage = '\n'.join(lines) # prefix with 'Usage:' return f'{prefix}{usage}\n\n' def _format_action_invocation(self, action: argparse.Action) -> str: if not action.option_strings: default = self._get_default_metavar_for_positional(action) (metavar,) = self._metavar_formatter(action, default)(1) return metavar parts: list[str] = [] # if the Optional doesn't take a value, format is: # -s, --long if action.nargs == 0: parts.extend(action.option_strings) return ', '.join(parts) # Begin cmd2 customization (less verbose) # if the Optional takes a value, format is: # -s, --long ARGS default = self._get_default_metavar_for_optional(action) args_string = self._format_args(action, default) return ', '.join(action.option_strings) + ' ' + args_string # End cmd2 customization def _determine_metavar( self, action: argparse.Action, default_metavar: Union[str, tuple[str, ...]], ) -> Union[str, tuple[str, ...]]: """Determine what to use as the metavar value of an action.""" if action.metavar is not None: result = action.metavar elif action.choices is not None: choice_strs = [str(choice) for choice in action.choices] # Begin cmd2 customization (added space after comma) result = f'{", ".join(choice_strs)}' # End cmd2 customization else: result = default_metavar return result def _metavar_formatter( self, action: argparse.Action, default_metavar: Union[str, tuple[str, ...]], ) -> Callable[[int], tuple[str, ...]]: metavar = self._determine_metavar(action, default_metavar) def format_tuple(tuple_size: int) -> tuple[str, ...]: if isinstance(metavar, tuple): return metavar return (metavar,) * tuple_size return format_tuple def _format_args(self, action: argparse.Action, default_metavar: Union[str, tuple[str, ...]]) -> str: """Handle ranged nargs and make other output less verbose.""" metavar = self._determine_metavar(action, default_metavar) metavar_formatter = self._metavar_formatter(action, default_metavar) # Handle nargs specified as a range nargs_range = action.get_nargs_range() # type: ignore[attr-defined] if nargs_range is not None: range_str = f'{nargs_range[0]}+' if nargs_range[1] == constants.INFINITY else f'{nargs_range[0]}..{nargs_range[1]}' return '{}{{{}}}'.format('%s' % metavar_formatter(1), range_str) # noqa: UP031 # Make this output less verbose. Do not customize the output when metavar is a # tuple of strings. Allow argparse's formatter to handle that instead. if isinstance(metavar, str): if action.nargs == ZERO_OR_MORE: return '[%s [...]]' % metavar_formatter(1) # noqa: UP031 if action.nargs == ONE_OR_MORE: return '%s [...]' % metavar_formatter(1) # noqa: UP031 if isinstance(action.nargs, int) and action.nargs > 1: return '{}{{{}}}'.format('%s' % metavar_formatter(1), action.nargs) # noqa: UP031 return super()._format_args(action, default_metavar) # type: ignore[arg-type] class Cmd2ArgumentParser(argparse.ArgumentParser): """Custom ArgumentParser class that improves error and help output.""" def __init__( self, prog: Optional[str] = None, usage: Optional[str] = None, description: Optional[str] = None, epilog: Optional[str] = None, parents: Sequence[argparse.ArgumentParser] = (), formatter_class: type[argparse.HelpFormatter] = Cmd2HelpFormatter, prefix_chars: str = '-', fromfile_prefix_chars: Optional[str] = None, argument_default: Optional[str] = None, conflict_handler: str = 'error', add_help: bool = True, allow_abbrev: bool = True, exit_on_error: bool = True, suggest_on_error: bool = False, color: bool = False, *, ap_completer_type: Optional[type['ArgparseCompleter']] = None, ) -> None: """Initialize the Cmd2ArgumentParser instance, a custom ArgumentParser added by cmd2. :param ap_completer_type: optional parameter which specifies a subclass of ArgparseCompleter for custom tab completion behavior on this parser. If this is None or not present, then cmd2 will use argparse_completer.DEFAULT_AP_COMPLETER when tab completing this parser's arguments """ kwargs: dict[str, bool] = {} if sys.version_info >= (3, 14): # Python >= 3.14 so pass new arguments to parent argparse.ArgumentParser class kwargs = { "suggest_on_error": suggest_on_error, "color": color, } super().__init__( prog=prog, usage=usage, description=description, epilog=epilog, parents=parents if parents else [], formatter_class=formatter_class, # type: ignore[arg-type] prefix_chars=prefix_chars, fromfile_prefix_chars=fromfile_prefix_chars, argument_default=argument_default, conflict_handler=conflict_handler, add_help=add_help, allow_abbrev=allow_abbrev, exit_on_error=exit_on_error, # added in Python 3.9 **kwargs, # added in Python 3.14 ) self.set_ap_completer_type(ap_completer_type) # type: ignore[attr-defined] def add_subparsers(self, **kwargs: Any) -> argparse._SubParsersAction: # type: ignore[type-arg] """Add a subcommand parser. Set a default title if one was not given.f :param kwargs: additional keyword arguments :return: argparse Subparser Action """ if 'title' not in kwargs: kwargs['title'] = 'subcommands' return super().add_subparsers(**kwargs) def error(self, message: str) -> NoReturn: """Print a usage message, including the message, to sys.stderr and terminates the program with a status code of 2. Custom override that applies custom formatting to the error message. """ lines = message.split('\n') formatted_message = '' for linum, line in enumerate(lines): if linum == 0: formatted_message = 'Error: ' + line else: formatted_message += '\n ' + line self.print_usage(sys.stderr) formatted_message = ansi.style_error(formatted_message) self.exit(2, f'{formatted_message}\n\n') def format_help(self) -> str: """Return a string containing a help message, including the program usage and information about the arguments. Copy of format_help() from argparse.ArgumentParser with tweaks to separately display required parameters. """ formatter = self._get_formatter() # usage formatter.add_usage(self.usage, self._actions, self._mutually_exclusive_groups) # type: ignore[arg-type] # description formatter.add_text(self.description) # Begin cmd2 customization (separate required and optional arguments) # positionals, optionals and user-defined groups for action_group in self._action_groups: if sys.version_info >= (3, 10): default_options_group = action_group.title == 'options' else: default_options_group = action_group.title == 'optional arguments' if default_options_group: # check if the arguments are required, group accordingly req_args = [] opt_args = [] for action in action_group._group_actions: if action.required: req_args.append(action) else: opt_args.append(action) # separately display required arguments formatter.start_section('required arguments') formatter.add_text(action_group.description) formatter.add_arguments(req_args) formatter.end_section() # now display truly optional arguments formatter.start_section('optional arguments') formatter.add_text(action_group.description) formatter.add_arguments(opt_args) formatter.end_section() else: formatter.start_section(action_group.title) formatter.add_text(action_group.description) formatter.add_arguments(action_group._group_actions) formatter.end_section() # End cmd2 customization # epilog formatter.add_text(self.epilog) # determine help from format above return formatter.format_help() + '\n' def _print_message(self, message: str, file: Optional[IO[str]] = None) -> None: # type: ignore[override] # Override _print_message to use style_aware_write() since we use ANSI escape characters to support color if message: if file is None: file = sys.stderr ansi.style_aware_write(file, message) class Cmd2AttributeWrapper: """Wraps a cmd2-specific attribute added to an argparse Namespace. This makes it easy to know which attributes in a Namespace are arguments from a parser and which were added by cmd2. """ def __init__(self, attribute: Any) -> None: """Initialize Cmd2AttributeWrapper instances.""" self.__attribute = attribute def get(self) -> Any: """Get the value of the attribute.""" return self.__attribute def set(self, new_val: Any) -> None: """Set the value of the attribute.""" self.__attribute = new_val # The default ArgumentParser class for a cmd2 app DEFAULT_ARGUMENT_PARSER: type[argparse.ArgumentParser] = Cmd2ArgumentParser def set_default_argument_parser_type(parser_type: type[argparse.ArgumentParser]) -> None: """Set the default ArgumentParser class for a cmd2 app. This must be called prior to loading cmd2.py if you want to override the parser for cmd2's built-in commands. See examples/override_parser.py. """ global DEFAULT_ARGUMENT_PARSER # noqa: PLW0603 DEFAULT_ARGUMENT_PARSER = parser_type