---

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.

This folder contains examples of using the built-in database handling methods with object and categories. Two object hierarchies are provided, one prototype-based, and the other class-based, in order to illustrate the differences between asserting predicates in a class and in a prototype:

The following objects are defined:

[114, 111, 111, 116]

root of the prototype hierarchy; declares and defines a public, dynamic predicate

[100, 101, 115, 99, 101, 110, 100, 97, 110, 116]

simple prototype extending the root prototype

[99, 108, 97, 115, 115]

root of the class hierarchy; declares and defines a public predicate

[109, 101, 116, 97, 99, 108, 97, 115, 115]

class metaclass

[105, 110, 115, 116, 97, 110, 99, 101]

simple instance of class class

[112, 114, 111, 116, 111, 116, 121, 112, 101]

simple prototype used to illustrate how the scope of asserted predicates depends on the target object (this, self, or an explicit object)

In addition, the file categories.lgt illustrates how to define category predicates that handle dynamic predicates in the context of "this" and in the context of "self".