__init__.py 文件源码

def enforce_signature(function):
    """
    Enforces the signature of the function by throwing TypeError's if invalid
    arguments are provided. The return value is not checked.

    You can annotate any parameter of your function with the desired type or a
    tuple of allowed types. If you annotate the function with a value, this
    value only will be allowed (useful especially for None). Example:

    >>> @enforce_signature
    ... def test(arg: bool, another: (int, None)):
    ...     pass
    ...
    >>> test(True, 5)
    >>> test(True, None)

    Any string value for any parameter e.g. would then trigger a TypeError.

    :param function: The function to check.
    """
    argspec = inspect.getfullargspec(function)
    annotations = argspec.annotations
    argnames = argspec.args

    unnamed_annotations = {}
    for i, arg in enumerate(argnames):
        if arg in annotations:
            unnamed_annotations[i] = (annotations[arg], arg)

    def decorated(*args, **kwargs):
        for i, annotation in unnamed_annotations.items():
            if i < len(args):
                assert_right_type(args[i], annotation[0], annotation[1])

        for argname, argval in kwargs.items():
            if argname in annotations:
                assert_right_type(argval, annotations[argname], argname)

        return function(*args, **kwargs)

    return decorated