bre.py 文件源码

def _apply_search_backrefs(pattern, flags=0):
    """Apply the search backrefs to the search pattern."""

    if isinstance(pattern, (compat.string_type, compat.binary_type)):
        re_verbose = bool(VERBOSE & flags)
        re_unicode = None
        if compat.PY3 and bool(ASCII & flags):
            re_unicode = False
        elif bool(UNICODE & flags):
            re_unicode = True
        pattern = SearchTemplate(pattern, re_verbose, re_unicode).apply()
    elif isinstance(pattern, RE_TYPE):
        if flags:
            raise ValueError("Cannot process flags argument with a compiled pattern!")
    else:
        raise TypeError("Not a string or compiled pattern!")
    return pattern