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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

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Design pattern: Singleton

Description: "Ensure a class has one instance, and provide a global point of access to it."

This pattern can be used with both classes and prototypes.

Given Logtalk supports for prototypes, implementing this pattern is trivial. Instead of using a class and write code to ensure a single class instance, we can simply use a prototype, which is its own global point of access. As applications can use a mix of prototypes and classes, there is nothing to be gained in implementing this pattern using classes.