Function pretty_callable

mypy/messages.py:3042–3160

Return a nice easily-readable representation of a callable type. For example: def [T <: int] f(self, x: int, y: T) -> None If skip_self is True, print an actual callable type, as it would appear when bound on an instance/class, rather than how it would appear in the defining

(tp: CallableType, options: Options, skip_self: bool = False)

def pretty_callable(tp: CallableType, options: Options, skip_self: bool = False) -> str:
    """Return a nice easily-readable representation of a callable type.
    For example:
        def [T <: int] f(self, x: int, y: T) -> None

    If skip_self is True, print an actual callable type, as it would appear
    when bound on an instance/class, rather than how it would appear in the
    defining statement.
    """
    s = ""
    asterisk = False
    slash = False
    for i in range(len(tp.arg_types)):
        if s:
            s += ", "
        if tp.arg_kinds[i].is_named() and not asterisk:
            s += "*, "
            asterisk = True
        if tp.arg_kinds[i] == ARG_STAR:
            s += "*"
            asterisk = True
        if tp.arg_kinds[i] == ARG_STAR2:
            s += "**"
        name = tp.arg_names[i]
        if not name and not options.reveal_verbose_types:
            # Avoid ambiguous (and weird) formatting for anonymous args/kwargs.
            if tp.arg_kinds[i] == ARG_STAR and isinstance(tp.arg_types[i], UnpackType):
                name = "args"
            elif tp.arg_kinds[i] == ARG_STAR2 and tp.unpack_kwargs:
                name = "kwargs"
        if name:
            s += name + ": "
        type_str = format_type_bare(tp.arg_types[i], options)
        if tp.arg_kinds[i] == ARG_STAR2 and tp.unpack_kwargs:
            if options.reveal_verbose_types:
                type_str = f"Unpack[{type_str}]"
            else:
                type_str = f"**{type_str}"
        s += type_str
        if tp.arg_kinds[i].is_optional():
            s += " = ..."
        if (
            not slash
            and tp.arg_kinds[i].is_positional()
            and name is None
            and (
                i == len(tp.arg_types) - 1
                or (tp.arg_names[i + 1] is not None or not tp.arg_kinds[i + 1].is_positional())
            )
        ):
            s += ", /"
            slash = True

    definition = get_func_def(tp)

    # Extract function name, prefer the "human-readable" name if available.
    func_name = None
    if tp.name: