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This file is part of Logtalk https://logtalk.org/ SPDX-FileCopyrightText: 2014-2026 Paulo Moura <pmoura@logtalk.org> SPDX-FileCopyrightText: 2004-2005 Daniel L. Dudley 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.

iso8601

ISO 8601 (and European civil calendar) compliant library of date and time (clock) related predicates. That is, an ISO 8601 handler.

The library supports date representations plus ISO 8601 duration and interval string conversions using duration_string/2 and interval_string/2.

An ISO 8601 duration string represents a time amount (e.g. P3D for three days or P1Y2M3DT4H5M6S for a mixed date/time duration).

An ISO 8601 interval string represents a time interval using two parts separated by /, where each part can be a date or a duration (e.g. 2026-02-25/2026-03-01 or 2026-02-25/P3D).

Author: Daniel L. Dudley Created: 2004-02-18

Modified: 2014-09-26 (to use the os library object to get the current date) Modified: 2026-02-25 (to add duration_string/2 and interval_string/2 predicates)

API documentation

Open the [../../apis/library_index.html#iso8601](../../apis/library_index.html#iso8601) link in a web browser.

Loading

To load all entities in this library, load the loader.lgt file:

| ?- logtalk_load(iso8601(loader)).

Testing

To test this library predicates, load the tester.lgt file:

| ?- logtalk_load(iso8601(tester)).