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This file is part of Logtalk https://logtalk.org/ SPDX-FileCopyrightText: 1998-2023 Paulo Moura <pmoura@logtalk.org> SPDX-License-Identifier: Apache-2.0

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.

To load this example and for sample queries, please see the SCRIPT.txt file.

Example adapted from the chapter "Classifying Prototype-Based Programming Languages" by Christophe Dony, Jacques Malenfant, and Daniel Bardou, found on the book "Prototype-Based Programming - Concepts, Languages, and Applications" published by Springer.

This prototype programming example illustrates how we can do both property sharing and value sharing in Logtalk by calling the built-in predicate modification methods asserta/1, assertz/1, and retract/1 either in the context of "this" or in the context of "self".

In this example we have a prototype, joe_person, containing general data on Joe such as its age, name, or address, and four descendant prototypes or viewpoints, joe_sportsman, joe_employee, joe_chess_player, and joe_film_enthusiast. Each descendant contains data related to a particular viewpoint about Joe.