Mini Shell

# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.


class Formatter:

    @classmethod
    def serialize(cls, value):
        """Return a string representing the formatted value"""
        raise NotImplementedError

    @classmethod
    def deserialize(cls, value):
        """Return a formatted object representing the value"""
        raise NotImplementedError


class BoolStr(Formatter):

    @classmethod
    def deserialize(cls, value):
        """Convert a boolean string to a boolean"""
        expr = str(value).lower()
        if "true" == expr:
            return True
        elif "false" == expr:
            return False
        else:
            raise ValueError("Unable to deserialize boolean string: %s"
                             % value)

    @classmethod
    def serialize(cls, value):
        """Convert a boolean to a boolean string"""
        if isinstance(value, bool):
            if value:
                return "true"
            else:
                return "false"
        else:
            raise ValueError("Unable to serialize boolean string: %s"
                             % value)