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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.

Logtalk provides objects, protocols, and categories as first-class entities. Relations between entities define patterns of code reuse and the roles played by the entities. For example, when an object instantiates another object, the first object plays the role of an instance and the second object plays the role of a class. An extends relation between two objects implies that both objects play the role of prototypes, with one of them extending the other, its parent prototype.

This simple example illustrates the different roles an object can play. See the comments in the roles.lgt file for detailed explanations.