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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('creational/lazy_initialization/loader')). ...

% access/create an instance for key "apple":

| ?- fruit::new(apple, Instance).

Instance = o1 yes

% access/create an instance for key "banana":

| ?- fruit::new(banana, Instance).

Instance = o2 yes

% access/create an instance for key "apple":

| ?- fruit::new(apple, Instance).

Instance = o1 yes

% show all initialized keys:

| ?- fruit::show_all.

apple banana yes