enumarg.py

# Copyright (C) 2022 luckytyphlosion
#
# This program 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 2 of the License, or
# (at your option) any later version.
#
# This program 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 this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

class EnumArgTable:
    __slots__ = ("enum_to_val", "valid_values")

    def __init__(self, enum_to_val):
        self.enum_to_val = enum_to_val
        self.valid_values = set(enum_to_val.values())

    def parse_enum_arg(self, enum_arg, error_message=None):
        try:
            enum_value = int(enum_arg)
            if enum_value in self.valid_values:
                return enum_value
        except ValueError:
            pass

        try:
            return self.enum_to_val[enum_arg]
        except KeyError as e:
            if error_message is None:
                raise RuntimeError(f"Unknown enum_arg value \"{enum_arg}\"!") from e
            else:
                raise RuntimeError(error_message.format(enum_arg)) from e