#!/usr/bin/env python3
## vi: tabstop=4 shiftwidth=4 softtabstop=4 expandtab
## ---------------------------------------------------------------------
##
## Copyright (C) 2020 by the adcc authors
##
## This file is part of adcc.
##
## adcc is free software: you can redistribute it and/or modify
## it under the terms of the GNU General Public License as published
## by the Free Software Foundation, either version 3 of the License, or
## (at your option) any later version.
##
## adcc is distributed in the hope that it will be useful,
## but WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
## GNU General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with adcc. If not, see <http://www.gnu.org/licenses/>.
##
## ---------------------------------------------------------------------
import sys


def __getattr__(attr):
    """
    Return a multi-dimensional block string like 'o1o2v1v1'
    when requesting the attribute 'ocvv'.
    """
    if any(c not in ["o", "v", "c"] for c in attr):
        raise AttributeError
    mapping = {"o": "o1", "v": "v1", "c": "o2"}
    return "".join(mapping[c] for c in attr)


# Dirty hack to support __getattr__ in python 3.6
if sys.version_info <= (3, 7):
    class GetAttr:
        def __getattr__(self, attr):
            return __getattr__(attr)
    sys.modules[__name__] = GetAttr()
