Class Argument

invoke/parser/argument.py:7–178

A command-line argument/flag. :param name: Syntactic sugar for ``names=[ ]``. Giving both ``name`` and ``names`` is invalid. :param names: List of valid identifiers for this argument. For example, a "help" argument may be defined with a name list of

class Argument:
    """
    A command-line argument/flag.

    :param name:
        Syntactic sugar for ``names=[<name>]``. Giving both ``name`` and
        ``names`` is invalid.
    :param names:
        List of valid identifiers for this argument. For example, a "help"
        argument may be defined with a name list of ``['-h', '--help']``.
    :param kind:
        Type factory & parser hint. E.g. ``int`` will turn the default text
        value parsed, into a Python integer; and ``bool`` will tell the
        parser not to expect an actual value but to treat the argument as a
        toggle/flag.
    :param default:
        Default value made available to the parser if no value is given on the
        command line.
    :param help:
        Help text, intended for use with ``--help``.
    :param positional:
        Whether or not this argument&#x27;s value may be given positionally. When
        ``False`` (default) arguments must be explicitly named.
    :param optional:
        Whether or not this (non-``bool``) argument requires a value.
    :param incrementable:
        Whether or not this (``int``) argument is to be incremented instead of
        overwritten/assigned to.
    :param attr_name:
        A Python identifier/attribute friendly name, typically filled in with
        the underscored version when ``name``/``names`` contain dashes.

    .. versionadded:: 1.0
    """

    def __init__(
        self,
        name: Optional[str] = None,
        names: Iterable[str] = (),
        kind: Any = str,
        default: Optional[Any] = None,
        help: Optional[str] = None,
        positional: bool = False,
        optional: bool = False,
        incrementable: bool = False,
        attr_name: Optional[str] = None,
    ) -> None:
        if name and names:
            raise TypeError(
                "Cannot give both 'name' and 'names' arguments! Pick one."
            )
        if not (name or names):
            raise TypeError("An Argument must have at least one name.")
        if names:
            self.names = tuple(names)
        elif name and not names:
            self.names = (name,)
        self.kind = kind