Function matches_re

src/attr/validators.py:152–197

r""" A validator that raises `ValueError` if the initializer is called with a string that doesn't match *regex*. Args: regex (str, re.Pattern): A regex string or precompiled pattern to match against flags (int): Flags that will be passed to the u

(regex, flags=0, func=None)

def matches_re(regex, flags=0, func=None):
    r"""
    A validator that raises `ValueError` if the initializer is called with a
    string that doesn't match *regex*.

    Args:
        regex (str, re.Pattern):
            A regex string or precompiled pattern to match against

        flags (int):
            Flags that will be passed to the underlying re function (default 0)

        func (typing.Callable):
            Which underlying `re` function to call. Valid options are
            `re.fullmatch`, `re.search`, and `re.match`; the default `None`
            means `re.fullmatch`. For performance reasons, the pattern is
            always precompiled using `re.compile`.

    .. versionadded:: 19.2.0
    .. versionchanged:: 21.3.0 *regex* can be a pre-compiled pattern.
    """
    valid_funcs = (re.fullmatch, None, re.search, re.match)
    if func not in valid_funcs:
        msg = "'func' must be one of {}.".format(
            ", ".join(
                sorted((e and e.__name__) or "None" for e in set(valid_funcs))
            )
        )
        raise ValueError(msg)

    if isinstance(regex, Pattern):
        if flags:
            msg = "'flags' can only be used with a string pattern; pass flags to re.compile() instead"
            raise TypeError(msg)
        pattern = regex
    else:
        pattern = re.compile(regex, flags)

    if func is re.match:
        match_func = pattern.match
    elif func is re.search:
        match_func = pattern.search
    else:
        match_func = pattern.fullmatch

    return _MatchesReValidator(pattern, match_func)


@attrs(repr=False, slots=True, unsafe_hash=True)