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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.

This example is inspired by a StackOverflow question for which a sketch of a Logtalk-based solution was provided:

http://stackoverflow.com/questions/26119110/knowledge-representation-in-prolog-how-to-store-data

It illustrates a possible solution for representing structured data using objects and also hot patching of running code. It also shows when a mixed representation using both data objects and Prolog facts can be managed.

The main files defined in this example are:

• specs.lgt defines the recipe protocol, recipep, declaring recipe description predicates and a prototype object, proto_recipe, defining handy predicates for summarizing recipe information
• recipes.lgt defines some recipes represented as objects
• parametric.lgt defines some recipes represented as facts for a recipe/3 predicate plus a recipe/3 parametric object and a recipe/1 predicate for enumerating recipes while abstracting their representation
• patch_1.lgt and patch_2.lgt categories used to illustrate hot patching of the example objects