---

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 an object which implements a translator from first-order predicate logic propositions to conjunctive normal form and to clausal form. The translator code is partially based on code published in the book "Programming in Prolog" by W. F. Clocksin and C. S. Mellish.

The following operators are used for representing logic connectives:

negation:[126]

disjunction:[118]

conjunction:[38]

implication:[61, 62]

equivalence:[60, 61, 62]

Quantifiers are represented using the following notation:

universal:[97, 108, 108, 40, 88, 44, 32, 80, 41]

existential:[101, 120, 105, 115, 116, 115, 40, 88, 44, 32, 80, 41]

The two main object predicates are translate/2 and step_by_step/2. The first predicate, translate/2, translate a logic proposition to a list of clauses. The second predicate, step_by_step/2, performs the same translations as translate/2 but also prints the results of each conversion step.