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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.

% start by loading the design pattern sample implementations:

| ?- logtalk_load(design_patterns('structural/twin/loader')). ...

% each object can answer its messages and the messages for its % twin object, thanks to message forwarding:

| ?- a_date::year(Year).

Year = 2018 yes

| ?- a_date::hour(Hour).

Hour = 11 yes

| ?- a_time::minutes(Minutes).

Minutes = 27 yes

| ?- a_time::day(Day).

Day = 13 yes

% we can also create twins dynamically:

| ?- time::new(twin_time, twin_date, [hour(12),minutes(37),seconds(17)]).

yes

| ?- date::new(twin_date, twin_time, [year(2003),month(9),day(23)]).

yes

| ?- twin_time::year(Year).

Year = 2003 yes

| ?- twin_date::seconds(Seconds).

Seconds = 17 yes